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A mission to prepare Australia for future droughts

We’ve launched our Drought Resilience Mission to reduce the impacts of droughts in Australia and enable faster recovery.

By Darius Koreis 8 September 2021 3 min read

Eastern and southern Australia are emerging from a widespread and severe drought. For many farmers, drought has meant disruption to crop and livestock production, and loss of income.

Impacts have been felt not just on the farm. Some regional communities ran out of water or came close to running out of water. And while many farmers and regional communities have recently celebrated the arrival of rain, we know the next drought is coming.

As Australia faces a future of more frequent and severe droughts, it’s critical that we come up with solutions and quickly .

That’s why we’ve launched our Drought Resilience Mission to tackle this major challenge. We’ve worked with industry, government and communities to develop this Mission. Together this decade, we will strive to reduce the impacts of droughts in Australia and enable faster recovery.

Our Drought Resilience Mission has come at a critical time. For Drought Resilience Mission Lead, Dr Graham Bonnett, the problem is the return to drought is never far away.

“In a country the size of Australia, the next drought could come at any time or anywhere," Graham says.

“We can’t control the weather, but we can better prepare for times when water is scarce so that farms and communities can best adapt.

“We need to take advantage of times like now when it has been raining. It’s our opportunity to prepare for future droughts, and not leave it for when it is too late," he says.

A key aspect of our Drought Resilience Mission's focus is on developing innovation to assist farmers.

Drought preparation needs more options

The Mission is helping farmers develop drought mitigation and water use plans fit for their farm and local weather.

Graham says there is evidence that through adopting new water-efficient technologies and practices, farmers have been maintaining yields despite less rainfall.

For example, building on practices like sowing grains earlier, we are coming up with ways to take advantage of a new breed of wheat. It has a longer coleoptile, which is the sheath that protects the young shoot. This genetic trait allows deeper planting when there is soil moisture below the surface to increase planting opportunities.

Developing new decision-making tools will also allow future adaptation to drought.

For example, matching animal stock numbers to available feed is a decision that livestock producers need to make. We are exploring a new tool to test destocking strategies based on the genetic information of animals, rather than their age, which would facilitate quicker recovery from drought.

A leg up for regional Australia

Drought doesn't just impact life on the farm. For many regional communities, agriculture is the lifeblood of their local economies. The main streets of regional towns feel downturns just as acutely as farmers do when spending dries up.

Unfortunately, the impacts of limited water supply do not end there. During Australia's recent drought, many communities approached ‘Day Zero’ — when their town water supplies would run out. Some towns hit that threshold and needed to transport water in from elsewhere.

That's why another key focus for the Mission is looking at ways to improve regional water security through developments such as water banking.

"Water banking involves replenishing underground aquifers when water is more available and recovering it during droughts," Graham says.

"We’re developing projects to demonstrate technologies that aim to improve the water security of regional communities."

As part of the Mission, we are also seeking to work with communities to help them plan pathways to diversify their economies, so they aren’t as reliant on industries that rely heavily on water. This will ensure communities are more resilient during times of drought.

Reducing drought impacts in Australia

City dwellers could also benefit from improved drought resilience. Our capital cities are not immune from water shortages and drought-related events, such as dust storms. Working with farmers and land managers to protect ground cover will prevent valuable topsoil from being gathered by wind.

The Drought Resilience Mission aims to reduce the impacts of drought by 30 per cent by 2030, a goal Graham says is achievable.

“We aren’t approaching this from a standing start. Between us and our partners, we have incredible breadth and scope in our knowledge and capabilities,” he says.

"New scientific advances allow us to tackle the likelihood of more frequent drought. And now is the time to act before the next big drought is here."

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• Published: 24 February 2020

The role of climate variability in Australian drought

• Andrew D. King   ORCID: orcid.org/0000-0001-9006-5745 1 , 2 ,
• Andy J. Pitman 2 , 3 ,
• Benjamin J. Henley   ORCID: orcid.org/0000-0003-3940-1963 1 , 2 , 4 ,
• Anna M. Ukkola   ORCID: orcid.org/0000-0003-1207-3146 2 , 5 &
• Josephine R. Brown   ORCID: orcid.org/0000-0002-1100-7457 1 , 2  

Nature Climate Change volume  10 ,  pages 177–179 ( 2020 ) Cite this article

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Much of Australia has been in severe drought since at least 2017. Here we link Australian droughts to the absence of Pacific and Indian Ocean mode states that act as key drivers of drought-breaking rains. Predicting the impact of climate change on drought requires accurate modelling of these modes of variability.

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Acknowledgements

We thank the Bureau of Meteorology, the Bureau of Rural Sciences and CSIRO for providing the Australian Water Availability Project data. Several authors received funding through the Australian Research Council: A.D.K. (DE180100638), and A.J.P. and A.M.U. (CE170100023). B.J.H. received funding from an Australian Research Council Linkage Project (LP150100062), which was co-funded by Melbourne Water and the Victorian Department of Environment, Land, Water and Planning, and supported by the Australian Bureau of Meteorology.

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School of Earth Sciences, University of Melbourne, Parkville, Victoria, Australia

Andrew D. King, Benjamin J. Henley & Josephine R. Brown

ARC Centre of Excellence for Climate Extremes, University of New South Wales, Kensington, New South Wales, Australia

Andrew D. King, Andy J. Pitman, Benjamin J. Henley, Anna M. Ukkola & Josephine R. Brown

Climate Change Research Centre, University of New South Wales, Kensington, New South Wales, Australia

Andy J. Pitman

School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria, Australia

Benjamin J. Henley

Research School of Earth Sciences, Australian National University, Canberra, Australian Capital Territory, Australia

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A.D.K. conceived the study and performed the analysis. All authors contributed to the methodological design and the writing of the paper.

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King, A.D., Pitman, A.J., Henley, B.J. et al. The role of climate variability in Australian drought. Nat. Clim. Chang. 10 , 177–179 (2020). https://doi.org/10.1038/s41558-020-0718-z

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Spatiotemporal meteorological drought assessment: a case study in south-east Australia

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• Published: 06 October 2021
• Volume 111 , pages 305–332, ( 2022 )

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• Gokhan Yildirim 1 &
• Ataur Rahman   ORCID: orcid.org/0000-0001-7152-9006 1  

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An understanding on different aspects of droughts is crucial for effective water resources management. Australia has experienced notable droughts in recent years. The present study utilises Effective Drought Index (EDI) and Standardized Precipitation Index (SPI) based on six time horizons (3, 6, 9, 12, 24, and 36 months) to evaluate drought parameters such as magnitude, duration, and intensity with their onset and end in south-east Australia using data from 45 rainfall stations. Maximum drought quantities determined using SPI and EDI, with average data length of 125 years, have been mapped by spline interpolation technique. Furthermore, average drought parameters for each of the SPIs and EDI have been investigated and spatial distributions of drought quantities have been exhibited. In the study area, SPIs based on different time scales (either short term or long term) have detected the maximum drought severity, duration, and/or intensity (at least one of the parameters) between 2013 and 2019. It has been found that south-east Australia had faced one of the most intense droughts during 2013 to 2019. It has also been found that the longest duration of drought has been in southern and eastern coasts of the study area. Generated maps based on average EDI values have depicted that the north-western and central parts of the study area have experienced the longest and strongest drought, whereas higher-intensity drought has been found to be dominating the eastern and southern parts of the study area. Higher frequency of the number of droughts has been found mostly in the east and south of the study area in terms of moderate, severe, and extreme droughts. The generated spatial maps of SPIs and EDI in this study help to identify the most drought-prone and vulnerable parts within south-east Australia. The drought maps developed for south-eastern Australia by this spatiotemporal analysis can be a key tool to policymakers for mitigation, risk assessment, and drought preparedness planning.

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Yildirim, G., Rahman, A. Spatiotemporal meteorological drought assessment: a case study in south-east Australia. Nat Hazards 111 , 305–332 (2022). https://doi.org/10.1007/s11069-021-05055-3

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Case studies

A changing climate, changing water management practices and environmental change are all impacting the way in which the Yorta Yorta people access, harvest and use one of their traditional weaving sedges ( Carex tereticaulis ). Most of their Country is developed; land-use activities vary from multiple crop species of wheat and corn to dairy farms.

Source: Bureau of Meteorology, 2021

The weaving sedge is an ephemeral aquatic species that relies on regular seasonal watering from the Murray River, its associated waterways and rainfall. It grows throughout the area, known as Barmah. The Yorta Yorta people refer to this area as Pama.

The weaving sedge relies on multiple factors to maintain conditions that are favourable for healthy growth, such as inundation with water, soil health, climate and rainfall. A changing climate and changing water regimes are affecting the resilience of this species and, therefore, the availability of this important plant for traditional knowledge and cultural use by the Yorta Yorta people. Records show 2 important climatological events in south-east Australian history: the ‘federation drought’ at the turn of the 20th century and the ‘millennium drought’ at the turn of the 21st century ( Griggs et al. 2014 ) . They also show that a pattern of episodic flooding was evident before settlement and that cultural uses of traditional plant species were affected by these drier episodes ( Griggs et al. 2014 ) .

The impacts of low rainfall, hotter summers and a changing climate are evidence that these species are struggling to survive. This means that the Yorta Yorta people cannot harvest at this site and use the species in the same traditional setting as they had once done. Yorta Yorta Country and the weaving sedge are forced to adapt to change, and the Yorta Yorta people are forced to adapt as a result of these changes:

If this plant is no longer available on Country, then my connection to my heritage and our traditional practices have been impacted. If the plants are healthy, we can harvest the reed for weaving. If the plants are not healthy, the reeds won’t be healthy and cannot be used. This tells us that there is something wrong. This is our barometer check of healthy Country. (Denise Morgan-Bulled, 2020)

While improved water management and rainfall are seen as critical to supporting the weaving sedge, fire was recently applied to the sedge to see whether the recovery of this species was possible under adapted conditions:

To see Country burn – I felt a sense of calm; to see and feel fire – my skin felt good; to see and smell smoke – I felt I could breathe; to stand on Country – I felt strong. Country felt good that day, I felt good that day. (Sonia Cooper, 2020)

Immediately after the burn, rain fell and some parts of the forest were inaccessible, and some new growth was triggered. This project allowed the influence of fire to be investigated as an additional management tool to help recover the species. The response of the weaving sedge to fire provided cultural outcomes for traditional weaving species for the Yorta Yorta people.

Photos: S Cooper, 2020

Climate change is the most significant threat to the long-term outlook for the Great Barrier Reef region ( GBRMA 2019 ) . Although ocean temperatures are only one of several influences that pose a threat to the Reef (others include tropical cyclones, freshwater plumes and nutrient run-off from floods on land, and pests such as the crown-of-thorns starfish), they show the most clear-cut long-term trend, which is expected to continue in the future.

High marine temperatures can cause ‘bleaching’, when corals expel the symbiotic algae (zooxanthellae) living in their tissues, causing the coral to turn white. If high temperatures persist (or if other pressures further stress already bleached corals), the coral dies. Mass coral bleaching is when entire tracts or regions of a reef bleach.

Before 2016, only 2 mass coral bleaching events had occurred in the Great Barrier Reef, in 1998 and 2002. Following the event of 2016 (reported in the 2016 state of the environment report), there have been further mass bleaching events in 2017 and 2020; the 2016 and 2017 events were the first instance of mass bleaching in consecutive years. All of these bleaching events occurred during periods of abnormally high sea surface temperatures in the region. The 2016 and 2017 events were focused primarily on the northern and central Reef, leaving the southern portion largely unaffected; conversely, the 2020 event had its worst impacts in the south. The 2020 event, however, has led to comparatively limited coral mortality, with the 2020–21 summer providing favourable conditions for short-term recovery.

Sea surface temperatures have been rising consistently in the Great Barrier Reef region ( BOM 2021 ) . In February, the hottest month of the year, sea surface temperatures in the region have warmed by about 1 °C from 1900 to 2020 (see Figure 7). February 2016 was the first month on record to have a regional mean temperature above 29 °C (compared with the long-term February average of 28.0 °C), but the 2016 value of 29.1 °C was surpassed by 29.2 °C in February 2020. These very high monthly mean temperatures were associated with prolonged marine heatwaves affecting large parts of the region.

The most significant long-term decline in coral has been in the northern Great Barrier Reef (see case study: Australia’s changing reefs, in the Reef recovery and management section in the Marine chapter). Hard coral cover in this region was between 20% and 30% for most of the period from when records began in the early 1980s until 2015. There was then a sharp drop to a record low of 13% in 2017. There has been a minor recovery to 17% in 2020, and then a stronger recovery to 27% in 2021, supported by relatively favourable conditions for coral recovery in the summer of 2020–21, with no major marine heatwaves or severe cyclones. Hard coral cover on the central and southern Reef shows more variability between years, with both regions dropping to record lows of 11% in 2011 as a result of the impacts of severe tropical cyclones ( Yasi in the central Reef, Hamish in the south) before a rapid rebound. The central Reef reached 29% hard coral cover in 2016 before a fall to 14% in 2019 and a rebound to 26% in 2021. Other studies have found a decline of more than 50% from the 1990s to the present in the number of small, medium and large corals on the Reef ( Dietzel et al. 2020 ) . However, corals acclimatised to some extent to marine heatwaves in 2016 and 2017 ( Hughes et al. 2019 ) – less bleaching was found for a given warming threshold in 2017 than for the same amount of warming in 2016.

Rising ocean temperatures are not the only aspect of climate change with the potential to affect coral reefs. Coral can be adversely affected by ocean acidification and rising sea levels, although the former is so far likely to have had a negligible impact on coral compared with warming temperatures ( GBRMA 2019 ) . The occurrence of freshwater plumes, and associated input of sediments and nutrients (see the Marine chapter), from flooding of coastal rivers has been relatively frequent since the 1970s compared with the past 370 years as a whole ( Lough et al. 2015 ) , but, despite their severity on land, the floods in the Townsville region in early 2019 had only a minor impact on the Reef. Water quality in the Great Barrier Reef region is routinely reported by the Queensland Government through reef water quality report cards ( DES 2021 ) .

Tropical cyclones, such as Debbie in 2017 (see case study: Severe tropical cyclone Debbie, in the Tropical cyclones section in the Extreme events chapter) and Penny in 2019, have also impacted the Reef in the past few years, but there has not been a cyclone in the past 5 years on the scale of the category 5 systems Hamish (2009) and Yasi (2011).

Coral reefs are expected to continue to decline with further global warming. Projections reported by the Intergovernmental Panel on Climate Change ( IPCC 2018 ) indicate that coral reefs are expected to decline globally by a further 70–90% (relative to 2015) at 1.5 °C global warming, and by more than 99% at 2 °C global warming. However, there are large regional differences, and the Great Barrier Reef has, to date, recovered more rapidly after bleaching events than the larger-scale average. It is expected that the total number of tropical cyclones in the region will remain stable or decline, but that a greater proportion of the cyclones that do occur will be intense. The occurrence of extreme rainfall on land is likely to increase, even though changes to total rainfall are unclear ( GBRMA & CSIRO 2021 ) .

Parts of the Torres Strait islands are highly vulnerable to sea level rise. A number of the islands are very low lying, and coastal inundation and erosion are significant issues even in the current climate. The most acute issues cover 2 groups of islands: the 2 alluvial islands in the top western region (Boigu and Saibai) and a number of small coral cays in the central part of the Torres Strait islands.

In the top western islands, there have been several inundation events since 2005. In 2011, during a strong La Niña event, some inhabited areas of Saibai were inundated to a depth of up to 0.5 metres ( Systems Engineering Australia 2011 ) . Some of the central coral cays have experienced significant coastal erosion. In addition to direct impacts on inhabited areas of the islands, these events threaten impacts on graves and other significant cultural sites, as well as saltwater intrusion into landfills, wastewater treatment sites and groundwater. Although tropical cyclones are relatively rare in the islands compared with areas further south in northern Queensland, storm surge associated with tropical cyclones is another potential risk.

Observed rates of sea level rise in the region over the period 1993–2010 were about 6 millimetres per year, somewhat greater than the global average of 3–3.5 millimetres per year and consistent with a broader pattern of increased sea level rise in the western tropical Pacific over this period. It is as yet unclear what contribution, if any, variability in the behaviour of the El Niño–Southern Oscillation (particularly the predominance of La Niña in the late 2000s and early 2010s) has made to this locally increased sea level rise, and whether it is likely to be sustained. Planning in the islands is widely based on projected sea level rise of 0.8 metres by 2100 ( Green et al. 2010, Suppiah et al. 2011, TSRA 2014, Rainbird 2016 ) .

Significant works to adapt to sea level rise are already taking place. New seawalls have been completed on Saibai and Boigu islands, replacing earlier community-built seawalls that had previously failed, as well as on Poruma Island in the central coral cay region. Further seawalls are in the planning stage. It is expected that, with such infrastructure works, existing communities will remain viable for at least several decades. Relocation of communities to other islands is regarded as a highly culturally disruptive option and would be considered only as a last resort.

Sources: BOM (2020a), Trewin et al. (2021)

The period from 2017 to 2019 saw severe drought affecting many parts of Australia. The most significant rainfall deficiencies occurred in the northern part of the Murray–Darling Basin, in northern New South Wales and southern Queensland. Dry conditions began in these regions in late 2016, and 2017 and 2018 were both significantly drier than normal in these areas. Other areas that also began to experience significant multiyear drought during this period were Gippsland and eastern Tasmania, and parts of southern Western Australia.

In 2019, the dry conditions intensified and expanded to cover many parts of the country. The most acute dry conditions were again focused on the northern Murray–Darling Basin, where some areas on both sides of the New South Wales – Queensland border had annual rainfall in 2019 that was 70–80% below normal, and more than 40% below previous record lows. As an example, rainfall averaged over the Gwydir catchment in 2019 was 176 millimetres (mm), 74% below normal, and 49% below the previous record of 348 mm set in 1902. It was also exceptionally dry over much of Australia’s interior (where numerous locations had less than 30 mm for the year) and in parts of coastal New South Wales between the Hunter region and the Queensland border. The 2018−19 and 2019−20 wet seasons also had well-below-average rainfall over many tropical parts of Western Australia and the Northern Territory.

Averaged over the country, 2019 was Australia’s driest year on record, surpassing the previous record set in 1902. New South Wales and South Australia also had their driest years on record, with South Australia having a state average rainfall below 100 mm for the first time. A strong positive phase of the Indian Ocean Dipole was a major contributor to 2019’s dry conditions, especially in the second half of the year.

It was the driest 3-year period on record for the Murray–Darling Basin, with a Basin average of 917 mm (37% below normal), breaking the previous record of 1,037 mm set in 1965−67. The dry conditions were particularly concentrated in the cooler months of the year, which exacerbated the impacts on water availability and agriculture. The April–September period of 2017, 2018 and 2019 all ranked among the 10 driest on record for New South Wales.

The most significant multiyear droughts in the region were 1895−1903, 1937−46 and 1997−09 (the millennium drought). The recent drought did not persist as long as those events, but was more intense over a 2−3-year period. The millennium drought was most severe in the southern Murray–Darling Basin (and in areas of eastern Queensland and southern Victoria outside the Basin). The northern Basin was less severely affected, whereas in 2017−19 the southern Basin was less severely affected than the north. Snow depth in the Australian Alps, which is important for spring inflows into the southern Basin, was also above average in all 3 years, partly because of a lack of rain events to cause melting during the snow season.

The most acute phase of the widespread drought eased during 2020, which saw average to above-average rains over most of eastern Australia from February onwards. Some locally dry areas remained, particularly in the south-east quarter of Queensland, and many parts of southern Western Australia had another dry year.

Major impacts on water resources

The drought severely affected water availability in many areas. Water storage levels in the northern Murray–Darling Basin dropped to 5.4% in mid-January 2020 (see Figure 5, in the Dams and reservoirs section in the Inland water chapter), and many individual storages were below 10% of capacity. A gradual recovery began from February 2020, but levels did not exceed 30% until floods in March 2021. Many rivers in the region had record low flows or ceased to flow altogether, contributing to significant environmental impacts, including large-scale fish deaths in the Darling River in early 2019. At the peak of the drought in late 2019, numerous towns ran out of conventional water supplies and required water to be trucked in.

The drought also had a substantial impact on agriculture, especially in 2019. Crop production in New South Wales and Queensland in 2019 was about 70% below the 10-year average, and the national sheep flock was at its smallest since 1905.

Did climate change contribute to the drought?

No formal attribution study has been carried out on the drought as a whole. A study investigating the impact of climate change on various factors contributing to the fire weather conditions in Australia in 2019−20 found no attributable signal of anthropogenic climate change contributing to the dry conditions of July–December 2019, although it did find an attributable signal for other aspects of fire weather ( van Oldenborgh et al. 2021 ) .

Over the worst-affected areas of the northern Murray–Darling Basin, there is not a clear-cut downward long-term trend in rainfall. Rainfall since 2000, as in much of eastern Australia, has been broadly comparable with that in the first half of the 20th century, although lower than that between the 1950s and the 1990s. There is some evidence of a shift in rainfall away from the cool season and towards the warm season, which is consistent with the very low cool-season rainfall in each of 2017, 2018 and 2019.

Much of south-western and south-eastern Australia has experienced a substantial decline in rainfall in the past few decades, especially in the cool season (see Rainfall and snow ). The very dry conditions in much of southern Western Australia in 2018 and 2019 were consistent with this, although some other areas, such as south-western and central Victoria, were less affected by the 2017−19 drought than regions further north.

One clear-cut climate change signal was that of very high temperatures, particularly during the day and in the warmer months. The years 2019 and 2018 were the 2 warmest years on record averaged over the Murray–Darling Basin, and 2017 was fourth warmest; the 3-year period was 1.65 °C above the 1961−90 average. The high temperatures increased evaporative demand and created additional stress on ecosystems and crops. However, the dry conditions also contributed to frosts, especially in 2017 when some parts of southern inland New South Wales had their coldest average winter minimum temperatures on record. There were also damaging frosts in September 2018 and 2019.

Sources: VBRC (2009), BOM (2020c), van Oldenborgh et al. (2021)

The 2019−20 Australian bushfire season was exceptional in modern times. The first major fires occurred in north-eastern New South Wales and south-eastern Queensland in early September 2019. Fire was present in the temperate forests of eastern Australia almost continuously from September 2019 to February 2020. In spring 2019, the major focus of fire activity was in northern New South Wales and southern Queensland; from late November, it shifted to central and southern New South Wales, eastern Victoria and the Australian Capital Territory. Destructive fires also affected Kangaroo Island and the Adelaide Hills in South Australia. The most acute phase of the season ended in the second week of February after widespread heavy rain, although some fires continued to burn within containment lines for several weeks after that.

An estimated 5.8 million hectares of temperate forest was burnt, easily the largest area in a season since detailed records have been kept – an unprecedented 23% of temperate forests in south-east Australia was burnt. The burnt area extended almost unbroken from Bundanoon in New South Wales to Bairnsdale in Victoria, a distance of more than 500 kilometres (see the Extreme events chapter).

Thirty-three lives were lost directly, and many more are likely to have been lost indirectly as a result of smoke pollution. More than 3,000 homes were destroyed, and direct and indirect economic losses were estimated to have exceeded $10 billion. There were also major impacts on biodiversity, with many plant and animal communities severely affected (see the Biodiversity chapter) .

Weather conditions contributing to the fires

Severe drought affected much of Australia in 2019 (see case study: The 2017−19 Australian drought ). Most of the fire-affected areas had less than half their average rainfall in the second half of 2019. It was the driest July–December period on record for most of the eastern ranges of New South Wales, and adjacent areas of southern Queensland and eastern Victoria. The dry conditions led to unusually dry fuels, while the almost total absence of widespread significant rain events from September onwards meant that many fires, once established, burned for several weeks or months. This meant that, on individual days of extreme fire weather, there was already substantial active fire in the landscape in addition to any new ignitions that might occur. (In contrast, on Black Saturday in February 2009, all but one of the major fires started on that day.)

Extreme fire weather in the coastal ranges of eastern Australia is typically associated with strong westerly to north-westerly winds, bringing dry, warm air from inland Australia. Fires can move very rapidly under such conditions, and most loss of life and property occurs on such days. These winds are common in winter and spring, but become uncommon in a normal season from late spring onwards, especially north of Sydney. Some of the most extreme fire weather episodes were in the second week of November in northern New South Wales, when at one stage 17 emergency warnings were current, and on 30–31 December in southern New South Wales and eastern Victoria, when some fires moved more than 50 kilometres in 24 hours. There were significant losses in both events.

In 2019, there was a strong negative phase of the Southern Annular Mode (SAM; see Other climate influences ), which contributed to westerly wind events being more frequent and lasting further into the season than would occur in a normal year. The negative SAM phase was, in turn, linked to an abrupt warming of the upper atmosphere in Antarctica in September, which also contributed to an abnormally small Antarctic ozone hole (see the Antarctica chapter) ( Lim et al. 2021 ) . November was an unusually windy month over south-eastern Australia, and monthly average humidity was at record lows in many parts of eastern New South Wales in November and December.

The most commonly used indicator of fire weather is the Forest Fire Danger Index (FFDI), which combines dryness, wind and temperature. Numerous FFDI-based measures in 2019 were far beyond previous records. The FFDI reached more than 100 (catastrophic) in northern New South Wales as early as 6 September. In total, there were 21 days during spring 2019 when the FFDI averaged over north-eastern New South Wales reached 25 (very high) or above, far exceeding the previous record of 11 days and the long-term average of 2 days. Averaged over the full period, the FFDI for September–December 2019 was the highest on record over almost all of New South Wales and Queensland, as well as in most of South Australia except for the south-east, and in eastern Victoria.

Source: BOM (2019)

Did climate change contribute to the fire weather conditions?

Fire weather conditions combine temperature, humidity, wind and antecedent moisture (or its absence). A study of the fire weather conditions in 2019−20 found that anthropogenic climate change has induced a higher weather-related risk of such an extreme fire season, driven primarily by increases in temperature ( van Oldenborgh et al. 2021 ) . No attributable relationship was found between climate change and the risk of droughts similar to that of July−December 2019. These results roughly mirror those of a similar study into the weather conditions underlying fires in central Queensland in spring 2018 ( Lewis et al. 2020 ) .

The COVID-19 pandemic led to widespread shutdowns of activity in Australia and elsewhere during 2020. This contributed to sharp reductions in greenhouse gas emissions in most countries, as well as reduced emissions of other substances.

Preliminary estimates indicate that global greenhouse gas emissions arising from the consumption of fossil fuels in 2020 decreased by 7% from 2019 values ( Friedlingstein et al. 2020 ) . At the peak of global shutdowns in early April 2020, estimated reductions in global greenhouse gas emissions were 17% (about half from surface transport), and individual countries had peak reductions of 26% ( Le Quere et al. 2020 ) .

In Australia, reductions in emissions were slightly below the global average. There was a 5.0% decrease for 2020 compared with 2019, with the June and September quarters 6–8% below the corresponding quarters of 2019. This reflects the fact that, outside Victoria, COVID-19-related restrictions on activity in Australia in 2020 were less severe and prolonged than in many other countries.

The largest sectoral decrease was 12.1% for transport, including 11.5% from petrol consumption and 50.9% from jet fuel (Figure 20).

Source: DISER (2020b)

Not all the reduced emissions in 2020 were related to the pandemic – for example, there was a 2.5% decrease in agricultural emissions between 2018–19 and 2019–20, which largely reflects the impacts of drought conditions during 2019. Agricultural emissions increased again in the second half of 2020, with the year to December 2020 having no change from the year to December 2019. Emissions from electricity generation were down by 4.9%, but this largely reflects an increased share of renewable energy, with only small changes in total electricity demand.

At a global scale, the impact of 2020’s reduced emissions on temperatures is expected to be negligible. Modelling has found that the reduced emissions are expected to lead to cooling of 0.01 °C (±0.005 °C) by 2030 relative to a scenario where they did not occur ( Forster et al. 2020 ) . In the short term, the pandemic led to slight increases in global temperatures during 2020 ( Gettelman et al. 2020 ) , as reduced emissions of aerosols and particulates more than offset reduced greenhouse gas emissions (particularly in heavily industrialised land areas of the Northern Hemisphere). However, these aerosol effects are expected to be short-lived compared with the ongoing impacts of changes in greenhouse gas emissions.

We, the participants attending the Gathering, acknowledge the voices of the Gimuy Walubarra Yidinji and Yirraganydji, whose lands we meet upon in 2021.

Building on the 2018 statement from First Peoples on Yorta Yorta land, we as First Nation Peoples of Australia recognise that overwhelmingly scientific and traditional knowledge is demanding immediate action against the threats of climate change. When Country is healthy, we are healthy.

Our knowledge systems are interconnected with our environment and it relies on the health of Country. This knowledge is held by our Elders and passed on to the next generation. Solutions to climate change can be found in the landscapes and within our knowledge systems. Aboriginal and Torres Strait Islander peoples have the tools, knowledge, and practices to effectively contribute to the fight against climate change.

We have lived sustainably in Australia for over 100,000 years. First Nations people of Australia contribute the least to climate change, yet the impacts of climate change are affecting us most severely.

We at the Gathering are calling for the following:

• A commitment from Federal Government to financially support an annual First Nations-led dialogue on climate change. The annual dialogue should be a place where Aboriginal and Torres Strait Islanders can discuss the changing climate in their communities and is a valuable input to inform policy at all levels.
• −Domestic emissions reductions through enabling reliable renewable energy supply to off grid communities, Indigenous-led nature-based solutions.
• −Indigenous-led adaptation planning for communities and the recording and transmission of knowledges and experiences across the country.
• The establishment of a Torres Strait Island taskforce, led by First Nations peoples of the region, to drive critical and tangible climate change solutions for island communities under present and immediate threat.
• We call on all Australians to join us in acting on climate change and in protecting the environment. To work collaboratively with us, learn our laws and our ways and respect our knowledges to find solutions together to combat climate change.
• Climate action that links all levels of government so our people and communities can work collaboratively in an Indigenous-led fight against climate change.
• The right to manage Country. First Nations peoples must be involved in the national dialogue about climate change and be engaged on any decision that impacts us and our Country. We call for these rights to be respected and observed on an international, national, state and local level. Our knowledge must be included in climate management frameworks.
• To look beyond ourselves, to include flora and fauna in climate planning and climate management frameworks so the plants and animals that support us can be represented. We are seeing changes in the environment and the declining health of Country and people. We can see our native flora and fauna are suffering and the conditions of our lands, waters, seas and skies declining. For some of our people it is an emergency because the climate crisis has already caused widespread damage.

Our connection to Country represents climate science developed over countless generations, listen to us, work with us and together we can enact a change that will shape our future for all Australians.

During 2014–15, the Ltyentye Apurte Central Land Council Rangers and CSIRO scientists shared knowledge about climate change to improve understanding and regional records. Ltyentye Apurte Rangers started by assembling local data, including photographs and recollections, to construct their own weather and climate timeline (Figure 22). They compared this timeline with scientific weather and climate data (Figure 23), showing a strong alignment that allowed the rangers to see trends that had not been obvious before:

Timeline of major events, like floods, fires, droughts and other things people could remember … showed the knowledge of local people and how the events aligned with and matched weather patterns with those recorded with scientists. We … observed notable changes in those graphs and records, showed more days over 40 °C, also bigger floods happening in later times. (Ltyentye Apurte Ranger Coordinator, 2015)

Photo: Fiona Walsh

Source: Bureau of Meteorology

Arrernte Elders also provided information about changes on Country, summarised by the ranger coordinator as:

Indigenous people of central Australia have been carers for Country for generations, passing on important cultural knowledge for land management practices. Over time, our people have noticed changes in the weather and seasons. Seasons seem more mixed up. Bush tucker is not fruiting or flowering at the right time of year.

The rangers were very interested in helping Arrernte people understand more – one of the rangers said, ‘I’m going learn this, learn all this, and put it in Arrernte so my mob can understand it.’

The scientists and the rangers worked together to produce a book and a slideshow in English. The rangers then presented this to Arrernte community audiences, speaking in Arrernte. People were grateful to hear about it in their own language, commenting that they had seen a lot about climate change on television, but had not understood what it was about before. Many impacts and potential solutions were also identified, including changes to houses, increased shade, and greater access to the swimming pool and cool buildings.

The main road to the Ltyentye Apurte community where the rangers live and work is being threatened by an erosion gully that is rapidly expanding as a result of large rainfall events. These events are increasing in intensity and frequency due to climate change. Rangers undertook activities and co-learning about erosion, in collaboration with scientists and practitioners, and established a trial of a new way of managing erosion. They built a set of control banks along the contour in 1 small catchment. However, the trial was compromised by inconsistent management of free-ranging horses, which trampled the control banks and led to bank breaching during heavy rains. Rebuilding of the control banks is currently impeded by loss of access to necessary resources.

The problem of climate change for Aboriginal people in central Australia is enormous. In the words of Central Land Council Chair Sammy Wilson during the 2019 Global Climate Strike ( Central Land Council 2019 ) :

I call on them to spare a thought for Aboriginal people out bush who may not be able to travel to the strikes but who are already suffering most during our hotter, longer and drier summers … I am dreading another summer like the last one because it is especially tough on our old and sick people who live in overcrowded, poor quality houses. Sammy Wilson, Central Land Council Chair

Drought case studies

Protecting people from a changing climate: The case for resilience

About the authors.

This article is a collaborative effort by Harry Bowcott , Lori Fomenko, Alastair Hamilton , Mekala Krishnan , Mihir Mysore , Alexis Trittipo, and Oliver Walker.

The United Nations’ 2021 Intergovernmental Panel on Climate Change (IPCC) report stated —with higher confidence than ever before—that, without meaningful decarbonization, global temperatures will rise to at least 1.5°C above preindustrial levels within the next two decades. 1 Climate change 2021: The physical science basis , Intergovernmental Panel on Climate Change (IPCC), August 2021, ipcc.ch. This could have potentially dangerous and irreversible effects. A better understanding of how a changing climate could affect people around the world is a necessary first step toward defining solutions for protecting communities and building resilience. 2 For further details on how a changing climate will impact a range of socioeconomic systems, see “ Climate risk and response: Physical hazards and socioeconomic impacts ,” McKinsey Global Institute, January 16, 2020.

As part of our knowledge partnership with Race to Resilience at the UN Climate Change Conference of the Parties (COP26) in Glasgow, we have built a detailed, global assessment of the number of people exposed to four key physical climate hazards, primarily under two different warming scenarios. This paper lays out our methodology and our conclusions from this independent assessment.

A climate risk analysis focused on people: Our methodology in brief

Our research consists of a global analysis of the exposure of people’s lives and livelihoods to multiple hazards related to a changing climate. This analysis identifies people who are potentially vulnerable to four core climate hazards—heat stress, urban water stress, agricultural drought, and riverine and coastal flooding—even if warming is kept within 2.0°C above preindustrial levels.

Our methodology

The study integrates climate and socioeconomic data sources at a granular level to evaluate exposure to climate hazards. We used an ensemble mean of a selection of Coupled Model Intercomparison Project Phase 5 (CMIP5) global climate models under Representative Concentration Pathway (RCP) 8.5 —using a Shared Socioeconomic Pathway (SSP2) for urban water stress—with analysis conducted under two potential warming scenarios: global mean temperature increases above preindustrial levels of 1.5°C and 2.0°C. We sometimes use the shorthand of “1.5°C warming scenario” and “2.0°C warming scenario” to describe these scenarios. Our modeling of temperatures in 2030 refers to a multidecadal average between 2021 and 2040. When we say 2050, we refer to a multidecadal average between 2041 and 2060. These are considered relative to a reference period, which is dependent on hazard basis data availability (which we sometimes refer to as “today”).

We built our analysis by applying 2030 and 2050 population-growth projections to our 1.5°C and 2.0°C warming scenarios, respectively. This amount of warming by those time periods is consistent with an RCP 8.5 scenario, relative to the preindustrial average. Climate science makes extensive use of scenarios. We chose a higher emissions scenario of RCP 8.5 to measure the full inherent risk from a changing climate. Research also suggests that cumulative historical emissions, which indicate the actual degree of warming, have been in line with RCP 8.5. 1 For further details, see “ Climate risk and response ,” January 16, 2020, appendix; see also Philip B. Duffy, Spencer Glendon, and Christopher R. Schwalm, “RCP8.5 tracks cumulative CO2 emissions,” Proceedings of the National Academy of Sciences of the United States of America (PNAS) , August 2020, Volume 117, Number 33, pp. 19656–7, pnas.org. In some instances, we have also considered a scenario in which decarbonization actions limit warming and 1.5°C of warming relative to the preindustrial levels is only achieved in 2050, rather than in 2030. For our analysis we used models which differ to some extent on their exact amount of warming and timing, even across the same emissions scenario (RCP 8.5). Naturally, all forward-looking climate models are subject to uncertainty, and taking such an ensemble approach to our model allows us to account for some of that model uncertainty and error. 2 For a more detailed discussion of these uncertainties, see chapter 1 of “ Climate risk and response: Physical hazards and socioeconomic impacts ,” McKinsey Global Institute, January 16, 2020. However, the mean amount of warming typically seen across our ensemble of models is approximately 1.5°C by 2030 and 2.0°C by 2050.

Our analysis consisted of three major steps (see technical appendix for details on our methodology):

First, we divided the surface of the planet into a grid composed of five-kilometer cells, with climate hazards and socioeconomic data mapped for each cell.

Second, in each of those cells, we combined climate and socioeconomic data to estimate the number and vulnerability of people likely to be exposed to climate hazards. These data were categorized on the basis of severity and classified on the basis of exposure to one or more hazards at the grid-cell level.

Third, taking into account people’s vulnerability, we examined the potential impact of our four core hazards on the current and future global population. To do this, we assessed, globally, the number and vulnerability of people affected by different types and severities of hazards. We then aggregated the data from each cell up to the subnational, national, subcontinental, continental, and global levels to allow for comparison across countries.

It’s important to note that we carefully selected these four hazards because they capture the bulk of hazards likely to affect populations on a global scale. We did not account for a range of other hazards such as wildfires, extreme cold, and snow events. Further, our analysis accounts only for first-order effects of climate hazards and does not take into account secondary or indirect effects, which can have meaningful impact. Drought, for example, can lead to higher food prices and even migration—none of which are included in our analysis. Thus, the number of people affected by climate hazards is potentially underestimated in this work.

A focus on four main climate hazards

For our study, we used global data sets covering four key hazards: heat stress, urban water stress, agricultural drought, and riverine and coastal flooding. We relied on data from a selection of CMIP5 climate models, unless otherwise specified. For further details, see the technical appendix.

Heat stress

Heat stress can have meaningful impacts on lives and livelihoods as the climate changes. Heat stress is measured using wet-bulb temperature, which combines heat and humidity. We assess heat stress in the form of acute exposure to humid heat-wave occurrence as well as potential chronic loss in effective working hours, both of which depend on daily wet-bulb temperatures. Above a wet-bulb temperature of 35°C, heat stress can be fatal.

Acute humid heat waves are defined by the average wet-bulb temperature of the hottest six-hour period during a rolling three-day period in which the daily maximum wet-bulb temperature exceeds 34°C for three consecutive days. 3 Analysis of lethal heat waves in our previous McKinsey Global Institute report (see “ Climate risk and response ,” January 16, 2020) was limited to urban populations, and the temperature threshold was set to 34°C wet-bulb temperature under the assumption that the true wet-bulb temperature would actually be 35°C due to an additional 1°C from the urban heat-island effect. Heat-wave occurrence was calculated for each year for both a reference time period 4 The reference period for heat stress refers to the average between 1998 and 2017. and our two future time periods and translated into annual probabilities. Exposure was defined as anyone living in either an urban or rural location with at least a 2 percent annual probability of experiencing such a humid heat wave in any given year. Acute humid heat waves of 34°C or higher can be detrimental to health, even for a healthy and well-hydrated human resting in the shade, because the body begins to struggle with core body-temperature regulation and the likelihood of experiencing a heat stroke increases.

Chronic heat stress was assessed for select livelihoods and defined by processing daily mean air temperature and relative humidity data into a heat index and translating that into the fraction of average annual effective working hours lost due to heat exposure. This calculation was conducted following the methods of John P. Dunne et al., 5 John P. Dunne, Ronald J. Stouffer, and Jasmin G. John, “Reductions in labour capacity from heat stress under climate warming,” Nature Climate Change , 2013, Volume 3, Number 6, pp. 563–6, nature.com. using empirically corrected International Organization for Standardization (ISO) heat-exposure standards from Josh Foster et al. 6 Josh Foster et al., “A new paradigm to quantify the reduction of physical work capacity in the heat,” Medicine and Science in Sports and Exercise , 2019, Volume 51, Number 6S, p. 15, journals.lww.com.

We combined groups of people who were exposed to both chronic and acute heat stress to assess the aggregate number of people exposed. Heat stress can affect livelihoods, particularly for those employed in outdoor occupations, most prominently because an increased need for rest and a reduction in the body’s efficiency reduce effective working hours. Therefore, our analysis of potential exposure to chronic heat stress was limited to people estimated to be working in agriculture, crafts and trades, elementary, factory-based, and manufacturing occupations likely to experience at least a 5 percent loss of effective working hours on average annually. We excluded managers, professional staff, and others who are more likely to work indoors, in offices, or in other cooled environments from this analysis.

Urban water stress

Urban water stress 7 The reference period for water stress refers to the average between 1950 and 2010. often occurs in areas in which demand for water from residents, local industries, municipalities, and others exceeds the available supply. This issue can become progressively worse over time as demand for water continues to increase and supply either remains constant, decreases due to a changing climate, or even increases but not quickly enough to match demand. This can reduce urban residents’ access to drinking water or slow production in urban industry and agriculture.

Our analysis of water stress is limited to urban areas partially because water stress is primarily a demand-driven issue that is more influenced by socioeconomic factors than by changes in climate. We also wanted to avoid methodological overlap with our agricultural drought analysis, which mostly focused on rural areas.

We define urban water stress as the ratio of water demand to supply for urban areas globally. We used World Resources Institute (WRI) data for baseline water stress today and the SSP2 scenario for future water stress outlooks, where 2030 represents the 1.5°C warming scenario and 2040 represents the 2.0°C warming scenario. We only considered severe water stress, defined as withdrawals of 80 percent or more of the total supply, which WRI classifies as “extremely high” water stress.

We make a distinction for “most severe” urban water stress, defined as withdrawals of more than 100 percent of the total supply, to show how many people could be affected by water running out—a situation that will require meaningful interventions to avoid. However, for the sake of the overall exposure analysis, people exposed to the most severe category are considered to be exposed to “severe” water stress unless otherwise noted (exhibit).

Agricultural drought

Agricultural drought 8 The reference period for agricultural drought refers to the average between 1986 and 2005. is a slow-onset hazard defined by a period of months or years that is dry relative to a region’s normal precipitation and soil-moisture conditions, specifically, anomalously dry soils in areas where crops are grown. Drought can inhibit plant growth and reduce plant production, potentially leading to poor yields and crop failures. For more details, see the technical appendix.

Riverine and coastal flooding

We define flooding as the presence of water at least one centimeter deep on normally dry land. We analyze two types of flooding here: riverine flooding from rivers bursting their banks and coastal flooding from storm surges and rising sea levels pushing water onto coastal land. Both coastal and riverine flooding can damage property and infrastructure. In severe cases, they could lead to loss of life. 9 The reference period for riverine flooding refers to the average between 1960 and 1999; the reference period for coastal flooding refers to the average between 1979 and 2014. For more details, see the technical appendix.

Based on a combination of frequency and intensity metrics, we estimated three severity levels of each climate hazard: mild, moderate, and severe (exhibit).

Even when we only look at first-order effects, it is clear that building resilience and protecting people from climate hazards are critical. Our analysis provides data that may be used to identify the areas of highest potential exposure and vulnerability and to help build a case for investing in climate resilience on a global scale.

Our findings suggest the following conclusions:

• Under a scenario with 1.5°C of warming above preindustrial levels by 2030, almost half of the world’s population could be exposed to a climate hazard related to heat stress, drought, flood, or water stress in the next decade, up from 43 percent today 3 Climate science makes extensive use of scenarios; we have chosen Representative Concentration Pathway (RCP) 8.5 and a multimodel ensemble to best model the full inherent risk absent mitigation and adaption. Scenario 1 consists of a mean global temperature rise of 1.5°C above preindustrial levels, which is reached by about 2030 under this RCP; Scenario 2 consists of a mean global temperature rise of 2.0°C above preindustrial levels, reached around 2050 under this RCP. Following standard practice, future estimates for 2030 and 2050 represent average climatic behavior over multidecadal periods: 2030 represents the average of the 2021–2040 period, and 2050 represents the average of the 2041–2060 period. We also compare results with today, also based on multidecadal averages, which differ by hazard. For further details, see technical appendix. —and almost a quarter of the world’s population would be exposed to severe hazards. (For detailed explanations of these hazards and how we define “severe,” see sidebar “A climate risk analysis focused on people: Our methodology in brief.”)
• Indeed, as severe climate events become more common, even in a scenario where the world reaches 1.5°C of warming above preindustrial levels by 2050 rather than 2030, nearly one in four people could be exposed to a severe climate hazard that could affect their lives or livelihoods.
• Climate hazards are unevenly distributed. On average, lower-income countries are more likely to be exposed to certain climate hazards compared with many upper-income countries, primarily due to their geographical location but also to the nature of their economies. (That said, both warming scenarios outlined here are likely to expose a larger share of people in nearly all nations to one of the four modeled climate hazards compared with today.) Those who fall within the most vulnerable categories are also more likely to be exposed to a physical climate hazard.

These human-centric data can help leaders identify the best areas of focus and the scale of response needed to help people—particularly the most vulnerable—build their climate resilience.

A larger proportion of the global population could be exposed to a severe climate hazard compared with today

Under a scenario with 1.5°C of warming above preindustrial levels by 2030, almost half of the world’s population—approximately 5.0 billion people—could be exposed to a climate hazard related to heat stress, drought, flood, or water stress in the next decade, up from 43 percent (3.3 billion people) today.

In much of the discussion below, we focus on severe climate hazards to highlight the most significant effects from a changing climate. We find that regardless of whether warming is limited to 1.5°C or reaches 2.0°C above preindustrial levels by 2050, severe hazard occurrence is likely to increase, and a much larger proportion of the global population could be exposed compared with today (Exhibit 1).

This proportion could more than double, with approximately one in three people likely to be exposed to a severe hazard under a 2.0°C warming scenario by 2050, compared with an estimated one in six exposed today. This amounts to about 2.0 billion additional people likely to be exposed by 2050. Even in a scenario where aggressive decarbonization results in just 1.5°C of warming above preindustrial levels by 2050, the number of people exposed to severe climate hazards could still increase to nearly one in four of the total projected global population, compared with one in six today.

One-sixth of the total projected global population, or about 1.4 billion people, could be exposed to severe heat stress, either acute (humid heat waves) or chronic (lost effective working hours), under a 2.0°C warming scenario above preindustrial levels by 2050, compared with less than 1 percent, or about 0.1 billion people, likely to be exposed today (Exhibit 2).

Our results suggest that both the severity and the geographic reach of severe heat stress may increase to affect more people globally, despite modeled projections of population growth, population shifts from rural to urban areas, and economic migration. Our analysis does not attempt to account for climate-change-related migration or resilience interventions, which could decrease exposure by either forcing people to move away from hot spots or mitigating impacts from severe heat stress.

For those with livelihoods affected by severe chronic heat stress, it could become too hot to work outside during at least 25 percent of effective working hours in any given year. This would likely affect incomes and might even require certain industries to rethink their operations and the nature of workers’ roles. For outdoor workers, extreme heat exposure could also result in chronic exhaustion and other long-term health issues. Heat stress can cause reductions in worker productivity and hours worked due to physiological limits on the human body, as well as an increased need for rest.

We have already seen some of the impacts of acute heat stress in recent years. In the summer of 2010 in Russia, tens of thousands of people died of respiratory illness or heat stress during a large heat-wave event in which temperatures rose to more than 10°C (50°F) higher than average temperatures for those dates. One academic study claims “an approximate 80 percent probability” that the new record high temperature “would not have occurred without climate warming.” 4 Dim Coumou and Stefan Rahmstorf, “Increase of extreme events in a warming world,” Proceedings of the National Academy of Sciences of the United States of America (PNAS) , November 2011, Volume 108, Number 44, pp. 17905–9, pnas.org. To date these impacts have been isolated events, but the potential impact of heat stress on a much broader scale is possible in a 1.5°C or 2.0°C warming scenario in the coming decades.

While we did not assess second-order impacts, they could also be meaningful. Secondary impacts from heat stress may include loss of power, and therefore air conditioning, due to greater stress on electrical grids during acute heat waves, 5 Sofia Aivalioti, Electricity sector adaptation to heat waves , Sabin Center for Climate Change Law, Columbia University, 2015, academiccommons.columbia.edu. increased stress on hospitals due to increased emergency room visits and admission rates primarily during acute heat-stress events, 6 Climate change and extreme heat events , Centers for Disease Control and Prevention, 2015, cdc.gov. and migration driven primarily by impacts from chronic heat stress. 7 Mariam Traore Chazalnoël, Dina Ionesco, and Eva Mach, Extreme heat and migration , International Organization for Migration, United Nations, 2017, environmentalmigration.iom.int.

The rate of growth in global urban water demand is highly likely to outpace that of urban water supply under future warming and socioeconomic pathway scenarios, compared with the overall historical baseline period (1950–2010). In most geographies, this problem is primarily caused not by climate change but by population growth and a corresponding growth in demand for water. However, in some geographies, urban water stress can be exacerbated by the impact of climate change on water supply. In a 2.0°C warming scenario above preindustrial levels by 2050, about 800 million additional people could be living in urban areas under severe water stress compared with today (Exhibit 3). This could result in lack of access to water supplies for drinking, washing and cleaning, and maintaining industrial operations. In some areas, this could make a case for investment in infrastructure such as pipes and desalination plants to make up for the deficit.

Agricultural drought is most likely to directly affect people employed in the agricultural sector: in conditions of anomalously dry soils, plants do not have an adequate water supply, which inhibits plant growth and reduces production. This in turn could have adverse impacts on agricultural livelihoods.

In a scenario with warming 2.0°C above preindustrial levels by 2050, nearly 100 million people—or approximately one in seven of the total global rural population projected to be employed in the agricultural sector by 2050—could be exposed to a severe level of drought, defined as an average of seven to eight drought years per decade. This could severely diminish people’s ability to maintain a livelihood in rainfed agriculture. Additional irrigation would be required, placing further strain on water demand, and yields could still be reduced if exposed to other heat-related hazards.

While our analysis focused on the first-order effects of agricultural drought, the real-world impact could be much larger. Meaningful second-order effects of agricultural drought include reduced access to drinking water and widespread malnutrition. In addition, drought in regions with insufficient aid can cause infectious disease to spread.

Further, although our analysis did not cover food security, many other studies have posited that if people are unable to appropriately adapt, this level of warming would raise the risk of breadbasket failures and could lead to higher food prices. 8 For more on how a changing climate might affect global breadbaskets, see “ Will the world’s breadbaskets become less reliable? ,” McKinsey Global Institute, May 18, 2020.

Primarily as a result of surging demand exacerbated by climate change, 9 Salvatore Pascale et al., “Increasing risk of another Cape Town ‘Day Zero’ drought in the 21st century, Proceedings of the National Academy of Sciences of the United States of America (PNAS) , November 2020, Volume 117, Number 47, pp. 29495–503, pnas.org. Cape Town, South Africa, a semi-arid country, recently experienced a water shortage. From 2015 to 2018, unusually high temperatures contributed to higher rates of evaporation with less refresh due to low rainfall, contributing to decline in water reserves which fell to the point of emergency 10 “Cape Town’s Water is Running Out,” NASA Earth Observatory, January 14, 2018, earthobservatory.nasa.gov. —by January 2018, about 4.3 million residents of South Africa had endured years of constant restrictions on water use in both urban and agricultural settings. Area farmers recorded losses, and many agricultural workers lost their jobs. In the city, businesses were hit with steep water tariffs, jobs were lost, and residents had to ration water.

Under a scenario with warming 2.0°C above preindustrial levels by 2050, about 400 million people could be exposed to severe riverine or coastal flooding, which may breach existing defenses in place today. As the planet warms, patterns of flooding are likely to shift. This could lead to decreased flood depth in some regions and increases likely beyond the capacity of existing defenses in others.

Riverine floods can disrupt travel and supply chains, damage homes and infrastructure, and even lead to loss of life in extreme cases. The most vulnerable are likely to be disproportionately affected—fragile homes in informal coastal settlements are highly vulnerable to flood-related damages.

This analysis does not account for the secondary impacts of floods that may affect people. In rural areas, floods could cause the salinity of soil to increase, which in turn could damage agricultural productivity. Flooding could also make rural roads impassable, limiting residents’ ability to evacuate and their access to emergency response. Major floods sometimes lead to widespread impacts caused by population displacement, healthcare disruptions, food supply disruptions, drinking-water contamination, psychological trauma, and the spread of respiratory and insect-borne disease. 11 Christopher Ohl and Sue Tapsell, “Flooding and human health: The dangers posed are not always obvious,” British Medical Journal (BMJ) , 2000, Volume 321, Number 7270, pp. 1167–8, bmj.com; Shuili Du, C.B. Bhattacharya, and Sankar Sen, “Maximizing business returns to corporate social responsibility (CSR): The role of CSR communication,” International Journal of Management Reviews (IJMR) , 2010, Volume 12, Number 1, pp. 8–19, onlinelibrary.wiley.com. The severity of these impacts varies meaningfully across geographic and socioeconomic factors. 12 Roger Few et al., Floods, health and climate change: A strategic review , Tyndall Centre working paper, number 63, November 2004, unisdr.org.

People in lower-income countries tend to have higher levels of exposure to hazards

Our analysis suggests that exposure to climate hazards is unevenly distributed. Overall, a greater proportion of people living in lower-income countries are likely to be exposed to one or more climate hazards (Exhibit 4). Under a scenario with warming 2.0°C above preindustrial levels by 2050, more than half the total projected global population could be affected by a climate hazard. On the other hand, only 10 percent of the total population in high-income countries is likely to be exposed. That said, there could also be meaningful increases in overall exposure in developed nations. For example, based on 2050 population projections, about 160 million people in the United States—almost forty percent of the US population—could be exposed to at least one of the four climate hazards in a 2.0°C warming scenario by 2050.

In all, our analysis suggests that nearly twice as many highly vulnerable people (those estimated to have lower income and who may also have inadequate shelter, transportation, skills, or funds to protect themselves from climate risks) could be exposed to a climate hazard (Exhibit 5).

One of the implications of these findings is that certain countries are likely to be disproportionately affected. Two-thirds of the people who could be exposed to a climate hazard in a 2.0°C warming scenario by 2050 are concentrated in just ten countries. In two of these, Bangladesh and Pakistan, more than 90 percent of the population could be exposed to at least one climate hazard.

India’s vulnerability to climate hazards

Today, India accounts for more than 17 percent of the world’s population. In a scenario with 2.0°C warming above preindustrial levels by 2050, nearly 70 percent of India’s projected population, or 1.2 billion people, is likely to be exposed to one of the four climate hazards analyzed in this report, compared with the current exposure of nearly half of India’s population (0.7 billion). India could account for about 25 percent of the total global population likely to be exposed to a climate hazard under a 2.0°C warming scenario by 2050, relative to today.

Just as the absolute number of people likely to be exposed to hazards is increasing, so too is the proportion of people likely to be exposed to a severe climate hazard. Today, approximately one in six people in India are likely to be exposed to a severe climate hazard that puts lives and livelihoods at risk. Using 2050 population estimates and a scenario with 2.0°C warming above preindustrial levels by 2050, we estimate that this proportion could increase to nearly one in two people.

Severe heat stress is the primary culprit of severe climate hazard exposure, potentially affecting approximately 650 million residents of India by 2050 in the 2.0°C warming scenario, compared with just under ten million today (exhibit).

A vast number of people in India could also be exposed. Under a scenario with warming 2.0°C above preindustrial levels by 2050, nearly half of India’s projected population—approximately 850 million—could be exposed to a severe climate hazard. This equates to nearly one-quarter of the estimated 3.1 billion people likely to be exposed to a severe climate hazard globally by 2050 under a 2.0°C warming scenario (see sidebar “India’s vulnerability to climate hazards”).

Between now and 2050, population models 13 “Spatial Population Scenarios,” City University of New York and NCAR, updated August 2018, cgd.ucar.edu. project that the world could gain an additional 1.6 billion people, a proportion of whom are likely to be more exposed, more vulnerable, and less resilient to climate impacts.

For example, much of this population growth is likely to come from urban areas. Urbanization is likely to exacerbate the urban heat-island effect—in which human activities cause cities to be warmer than outlying areas—and humid heat waves could take an even greater toll. Urbanization is likely a driver in increased exposure of populations in coastal and riverine cities.

In India and other less developed economies, water stress is less of a climate problem and more of a socioeconomic problem. Our work and previous work on the topic has shown that increased water stress is mostly due to increases in demand—which is primarily driven by population growth in urban areas.

As labor shifts away from agriculture and other outdoor occupations toward indoor work, fewer people may be exposed to the effects of agricultural drought and heat stress. But on balance, many more people will likely be exposed to climate hazards by 2050 than today under either a 1.5°C or a 2.0°C warming scenario above preindustrial levels.

Many regions of the world are already experiencing elevated warming on a regional scale. It is estimated that 20 to 40 percent of today’s global population (depending on the temperature data set used) has experienced mean temperatures of at least 1.5°C higher than the preindustrial average in at least one season. 14 “Chapter 1: Framing and context,” Special report: Global warming of 1.5°C , International Panel on Climate Change (IPCC), 2018, ipcc.ch.

Mitigation will be critical to minimizing risk. However, much of the warming likely to occur in the next decade has already been “locked in” based on past emissions and physical inertia in the climate system. 15 H. Damon Matthews et al., “Focus on cumulative emissions, global carbon budgets, and the implications for climate mitigation targets,” Environmental Research Letters, January 2018, Volume 13, Number 1. Therefore, in addition to accelerating a path to lower emissions, leaders need to build resilience against climate events into their plans.

Around the world, there are examples of innovative ways to build resilience against climate hazards. For example, the regional government of Quintana Roo on Mexico’s Yucatán Peninsula insured its coral reefs in an arrangement with an insurance firm, providing incentives for the insurer to manage any degradation, 16 “World’s first coral reef insurance policy triggered by Hurricane Delta,” Nature Conservancy, December 7, 2020, nature.org. and a redesigned levee system put in place after Hurricane Katrina may have mitigated the worst effects of Hurricane Ida for the citizens of New Orleans. 17 Sarah McQuate, “UW engineer explains how the redesigned levee system in New Orleans helped mitigate the impact of Hurricane Ida,” University of Washington, September 2, 2021, washington.edu.

Nonstate actors may have particular opportunities to help build resilience. For instance, insurance companies may be in a position to encourage institutions to build resilience by offering insurance products for those that make the right investments. This can lower reliance on public money as the first source of funding for recovery from climate events. Civil-engineering companies can participate in innovative public–private partnerships to accelerate infrastructure projects. Companies in the agricultural and food sectors can help farmers around the world mitigate the effects that climate hazards can have on food production—for example, offers of financing can encourage farmers to make investments in resilience. The financial-services sector can get involved by offering better financing rates to borrowers who agree to disclose and reduce emissions and make progress on sustainability goals. And, among other actions, all companies can work to make their own operations and supply chains more resilient.

Accelerating this innovation, and scaling solutions that work quickly, could help us build resilience ahead of the most severe climate hazards.

Harry Bowcott is a senior partner in McKinsey’s London office, Lori Fomenko is a consultant in the Denver office, Alastair Hamilton is a partner in the London office, Mekala Krishnan is a partner at the McKinsey Global Institute (MGI) and a partner in the Boston office, Mihir Mysore is a partner in the Houston office, Alexis Trittipo is an associate partner in the New York office, and Oliver Walker is a director at Vivid Economics, part of McKinsey’s Sustainability Practice.

The authors wish to thank Shruti Badri, Riley Brady, Zach Bruick, Hauke Engel, Meredith Fish, Fabian Franzini, Kelly Kochanski, Romain Paniagua, Hamid Samandari, Humayun Tai, and Kasia Torkarska for their contributions to this article. They also wish to thank external adviser Guiling Wang and the Woodwell Climate Research Center.

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May 30 Another human case of bird flu has been detected in a dairy farm worker in Michigan—though the cases aren’t connected—and this is the first person in the U.S. to report respiratory symptoms connected to bird flu, though their symptoms are “resolving,” according to the Centers for Disease Control and Prevention.

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May 22 Michigan reported bird flu in a farmworker—the second U.S. human case tied to transmission from dairy cows—though the worker had a mild infection and has since recovered.

May 21 Australia reported its first human case of bird flu after a child became infected in March after traveling to India, though the child has since recovered after suffering from a “severe infection,” according to the Victorian Department of Health.

May 16 The USDA conducted a study, and discovered that after high levels of the virus was injected into beef, no trace was left after the meat was cooked medium to well done, though the virus was found in meat cooked to lower temperatures.

May 14 The Centers for Disease Control and Prevention released influenza A waste water data for the weeks ending in April 27 and May 4, and found several states like Alaska, California, Florida, Illinois and Kansas had unusually high levels, though the agency isn’t sure if the virus came from humans or animals, and isn’t able to differentiate between influenza A subtypes, meaning the H5N1 virus or other subtypes may have been detected.

May 10 The Food and Drug Administration announced it will commit an additional $8 million to ensure the commercial milk supply is safe, while the Department of Agriculture said it will pay up to $28,000 per farm to help mitigate the spread of the disease, totaling around $98 million in funds.

May 9 Some 70 people in Colorado are being monitored for bird flu due to potential exposure, and will be tested for the virus if they show any symptoms, the Colorado Department of Public Health told Forbes—it was not immediately clear how or when the people were potentially exposed.

May 1 The Department of Agriculture said it tested 30 grocery store ground beef products for bird flu and they all came back negative, reaffirming the meat supply is safe.

May 1 The Food and Drug Administration confirmed dairy products are still safe to consume, announcing it tested grocery store samples of products like infant formula, toddler milk, sour cream and cottage cheese, and no live traces of the bird flu virus were found, although some dead remnants were found in some of the food—though none in the baby products.

April 30 Wenqing Zhang, head of the World Health Organization's Global Influenza Programme, said during a news briefing "there is a risk for cows in other countries to be getting infected," with the bird flu virus, since it’s commonly spread through the movement of migratory birds.

April 29 The Department of Agriculture told Forbes it will begin testing ground beef samples from grocery stores in states with cow outbreaks, and test ground beef cooked at different temperatures and infected with the virus to determine if it's safe to eat.

April 24 The USDA said cow-to-cow transmission may be occurring due to the cows coming into contact with raw milk—and warned against humans and other animals, including pets, consuming unpasteurized milk to prevent potential infection.

April 18 Jeremy Farrar, chief scientist for the World Health Organization, said during a press conference the threat of bird flu spreading between humans was a “great concern,” since it’s evolved and has increasingly been infecting mammals (on land and sea), which means it could possibly spread to humans.

April 1 The CDC reported the second U.S. human case of bird flu in a Texas dairy farmer who became infected after contracting the virus from infected dairy cows, but said the person was already recovering.

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Can Bird Flu Spread Between Humans?

Bird flu doesn’t “transmit easily from person-to-person,” according to the World Health Organization. Bird flu rarely affects humans, and most previous cases came from close contact with infected poultry, according to the CDC. Because human-to-human spread of bird flu poses “pandemic potential,” each human case is investigated to rule out this type of infection. Though none have been confirmed, there are a few global cases—none in the U.S.—where human-to-human transmission of bird flu was thought to be “probable,” including in China , Thailand , Indonesia and Pakistan .

Is Bird Flu Fatal To Humans?

It is very deadly. Between January 2003 and March 28, 2024 there have been 888 human cases of bird flu infection in humans, according to a report by the World Health Organization. Of those 888 cases, 463 (52%) died. To date, only two people in the U.S. have contracted H5N1 bird flu, and they both were infected after coming into contact with sick animals. The most recent case was a dairy worker in Texas who became ill in March after interacting with sick dairy cows, though he only experienced pink eye. The first incident happened in 2022 when a person in Colorado contracted the disease from infected poultry, and fully recovered.

Is It Safe To Drink Milk Infected With Bird Flu?

Raw, unpasteurized milk is unsafe to drink, but pasteurized milk is fine, according to the FDA. Bird flu has been detected in both unpasteurized and pasteurized milk, but the FDA recommends manufacturers against making and selling unpasteurized milk since there’s a possibility consuming it may cause bird flu infection. However, the virus remnants in pasteurized milk have been deactivated by the heat during the pasteurization process , so this type of milk is still believed safe to consume.

Is It Safe To Consume Meat Infected With Bird Flu?

The CDC warns against eating raw meat or eggs from animals “confirmed or suspected” of having bird flu because of the possibility of transmission. However, no human has ever been infected with bird flu from eating properly prepared and cooked meat, according to the agency. The possibility of infected meat entering the food supply is “extremely low” due to rigorous inspection, so properly handled and cooked meat is safe to eat, according to the USDA. To know when meat is properly cooked, whole beef cuts must be cooked to an internal temperature of 145 degrees Fahrenheit, ground meat must be 160 degrees and poultry must be cooked to 165 degrees. Rare and medium rare steaks fall below this temperature. Properly cooked eggs with an internal temperature of 165 degrees Fahrenheit kills bacteria and viruses including bird flu, according to the CDC. “It doesn’t matter if they may or may not have [avian] influenza… runny eggs and rare pieces of meat” are never recommended, Francisco Diez-Gonzalez, director and professor for the Center for Food Safety at the University of Georgia, told Forbes. To “play it safe,” consumers should only eat fully cooked eggs and make sure “the yolks are firm with no runny parts,” Daisy May, veterinary surgeon with U.K.-based company Medivet, said .

What Are Bird Flu Symptoms In Humans?

Symptoms of bird flu include a fever, cough, headache, chills, shortness of breath or difficulty breathing, runny nose, congestion, sore throat, nausea or vomiting, diarrhea, pink eye, muscle aches and headache. However, the CDC advises it can’t be diagnosed based on symptoms alone, and laboratory testing is needed. This typically includes swabbing the nose or throat (the upper respiratory tract), or the lower respiratory tract for critically ill patients.

How Is Bird Flu Affecting Egg Prices?

This year’s egg prices have increased as production decreased due to bird flu outbreaks among poultry, according to the USDA. A dozen large, grade A eggs in the U.S. costed around $2.99 in March, up almost a dollar from the fall. However, this price is down from a record $4.82 in January 2023, which was also spiked by bird flu outbreaks . Earlier this month, Cal-Maine Foods—the country’s largest egg producer—temporarily halted egg production after over one million egg-laying hens and chickens were killed after being infected with bird flu.

Why Do Poultry Farmers Kill Chickens With Bird Flu?

Once chickens have been infected with bird flu, farmers quickly kill them to help control the spread of the virus, since bird flu is highly contagious and fatal in poultry. The USDA pays farmers for all birds and eggs that have to be killed because of bird flu, as an incentive to responsibly try and curb the spread of the disease. The USDA has spent over $1 billion in bird flu compensation for farmers since 2022, according to the nonprofit Food & Environment Reporting Network.

Is There A Vaccine For The Bird Flu (h5n1)?

The FDA has approved a few bird flu vaccines for humans. The U.S. has a stockpile of vaccines for H5N1 bird flu, but it wouldn’t be enough to vaccinate all Americans if an outbreak were to happen among humans. If a human outbreak does occur, the government plans to mass produce vaccines, which can take at least six months to make enough for the entire population. CSL Seqirus, the maker of one of the approved vaccines, expects to have 150 million vaccines ready within six months of an announcement of a human bird flu pandemic. Although there are approved vaccines for other variants designed for birds, there are none for the H5N1 variant circulating. However, the USDA began trials on H5N1 animal-specific vaccines in 2023.

Key Background

As of May 30, more than 92 million poultry (primarily chickens) in 48 states have been euthanized because of bird flu since 2022, and 57 dairy cow herds across nine states have tested positive, according to data from the CDC (unlike chickens, cows appear to recover from the virus). The USDA believes wild migratory birds are the original source of the cow outbreaks that recently has experts concerned it may mutate and spread more easily in humans, though the CDC said its risk to the public remains low . Farrar called the cattle infections in the U.S. a “huge concern,” urging public health officials to continue closely monitoring the situation “because it may evolve into transmitting in different ways.” The increased number of mammal bird flu infections since 2022 “could indicate that the virus is looking for new hosts, and of course, moving closer to people,” Andrea Garcia, vice president of science, medicine and public health for the American Medical Association, said . The first report of a walrus dying from bird flu was detected in April on one of Norway’s Arctic Islands, and the first U.S. dolphin infected with bird flu died back in 2022, according to a report published April 18. More than 10 human bird flu cases were reported to the World Health Organization in 2023, and all but one survived. Bird flu has devastated bird populations, and 67 countries reported the deaths of 131 million poultry in 2022 alone. Although bird flu typically infects wild birds and poultry, it’s spread to other animals during the outbreak, and at least 10 countries have reported outbreaks in mammals since 2022. Around 17,400 elephant seal pups died from bird flu in Argentina in 2023, and at least 24,000 sea lions died in South America the same year. Besides cattle, bird flu has been detected in over 200 other mammals—like seals, raccoons and bears—in the U.S. since 2022. Although rare, even domestic pets like dogs and cats are susceptible to the virus, and the FDA warns against giving unpasteurized milk to cats to avoid possible transmission.

On June 5, WHO confirmed the first human death of a strain of bird flu that’s never before been seen in humans and is separate from H5N1. A 59-year-old man in Mexico contracted H5N2, and died on April 24 after being hospitalized and developing a fever, diarrhea, nausea, shortness of breath and general discomfort. Cases of H5N2 have been reported in poultry in Mexico, but the man had no history with poultry or animals, WHO said. It’s unclear how he became infected. He was bedridden for weeks prior to the infection, and suffered from several other health conditions.

Further Reading

Another Bird Flu Variant Reaches Humans: What To Know About H5N2—After First-Ever Confirmed Death

WHO Warns Threat Of Bird Flu Spreading To Humans Is ‘Great Concern’ (Forbes)

One In Five Milk Samples From Across US Had Traces Of Bird Flu Virus, FDA Says (Forbes)

Can Pets Get Bird Flu? Here’s What To Know (Forbes)

Avian H5N1 (Bird) Flu: Why Experts Are Worried—And What You Should Know (Forbes)