Revealed: how climate breakdown is supercharging toll of extreme weather

Guardian analysis shows human-caused global heating is driving more frequent and deadly disasters across the planet, in most comprehensive compilation to date

The devastating intensification of extreme weather is laid bare today in a Guardian analysis that shows how people across the world are losing their lives and livelihoods due to more deadly and more frequent heatwaves, floods, wildfires and droughts brought by the climate crisis.

The analysis of hundreds of scientific studies – the most comprehensive compilation to date – demonstrates beyond any doubt how humanity’s vast carbon emissions are forcing the climate to disastrous new extremes. At least a dozen of the most serious events, from killer heatwaves to broiling seas, would have been all but impossible without human-caused global heating, the analysis found.

Most worryingly, all this is happening with a rise of just 1C in the planet’s average temperature. The role of global heating in supercharging extreme weather is happening at “astonishing speed”, scientists say.

“The world is changing fast and it’s already hurting us – that is the blunt summary,” said Prof Maarten van Aalst, the director of the International Red Cross Red Crescent Climate Centre. The world is currently on track for a rise of at least 2.5C. Based on what we have experienced so far, that would deliver death and destruction far greater than already suffered.

The studies analysed used a scientific technique called attribution to determine how much worse, or more likely, an extreme weather event was made by human-caused global heating. The technique’s power is in drawing a direct link between the disasters that people suffer through and the often abstract increase in atmospheric greenhouse gases caused by the mass burning of fossil fuels since the Industrial Revolution. It brings the scientific reality of the climate crisis crashing home.

The climate information website Carbon Brief compiled a new database of attribution studies of more than 500 events – every such study available – and shared it exclusively with the Guardian. The analysis of the database and interviews with the world’s leading attribution scientists shows beyond any doubt that we are already deep into the era of climate death and destruction.

The key findings

•The 12 events deemed virtually impossible without humanity’s destabilisation of the climate span the globe, including intense heatwaves in North America, Europe and Japan, soaring temperatures in Siberia and sweltering seas off Australia.
•Seventy-one per cent of the 500 extreme weather events and trends in the database were found to have been made more likely or more severe by human-caused climate change, including 93% of heatwaves, 68% of droughts and 56% of floods or heavy rain. Only 9% of the events were less likely, mostly cold snaps and snowstorms.
•One in three deaths caused by summer heat over the last three decades was the direct result of human-caused global heating, implying a toll of millions.
•Huge financial costs are also now attributable to human influence on the climate, such as $67bn of damages when Hurricane Harvey smashed into Texas and Louisiana in 2017, which was 75% of the total damages from the storm.
•Global heating has been hurting us for far longer than commonly assumed, with traces of its influence as far back as the heatwaves and droughts that triggered the infamous Dust Bowl in the US in the mid-1930s.

The continent that is home to nearly two-thirds of the human race is being hit by the climate storm just as hard as elsewhere. Most unequivocal was the finding that the extreme warmth across the region in 2016, which affected billions, “would not have been possible without climate change”.

Global heating supercharged the super typhoon Haiyan, which battered the Philippines in 2013, pushing up a storm surge that sent ocean water crashing inland by 20%, killing 7,000 people.

“I grew up seeing these typhoons devastating our communities,” said Tan, the youth activist. “These attribution studies aren’t just studies. Each statistic reflects a community that experienced that extreme weather event – a family, an individual, a student, a young person whose lives were devastated because of the climate crisis.”

China in particular is enduring a rollercoaster of extreme weather made worse by global heating. Exceptional rains at the start of 2019 were made 30% more likely and blocked out the sun in the Middle-Lower Yangtze Plain, cutting sunshine hours by 57% and reducing rice production.

By May that year, drought conditions had arrived in south-west China. The severe low rainfall event was made about six times more likely by human climate influence. Extreme wildfires followed in south China, with the weather-related risk ramped up sevenfold by global heating. In one conflagration, “a huge fireball was formed in an instant”, the authorities reported, killing 30 people.

A year later, it was heavy rain that struck south-west China in August. Flood waters reached the toes of the famous Leshan Giant Buddha statue for the first time since the communist state was formed in 1949. The deluge was made twice as likely by human influence. In 2020, heat plagued southern China – “hot events similar to [this] cannot occur under past climate,” researchers said.

India, Asia’s other population superpower, has been far less studied. But a rapid analysis found that the sweltering heat that hit north-west India and south-east Pakistan in March and April this year was made 30 times more likely by the climate crisis. A similar heatwave in 2010 was made 100 times more likely, scientists calculated.

Deadly fires in Indonesia in 2015 were boosted by high temperatures, the chances of which were “substantially increased” by human-induced climate change. The vast haze of smoke that engulfed the region, and kept millions of children out of school, is estimated to have killed 100,000 people.

The Arabian Gulf, which may face unsurvivable conditions in future, appears to have been barely assessed by attribution studies.

Australia may until recently have had a government that had little concern for the climate crisis, but the climate crisis remains an extraordinary concern for Australia.

In the notorious “black summer” of 2019-20 there were blazing bushfires, and the influence of global heating is now clear. The summer saw a high fire weather index, a measure of dangerous conditions, that was made four times more likely by global heating. Two years earlier, a baking summer in New South Wales was made “at least 50 times more likely”, while a record warm Australian spring in 2014 would probably never have occurred without human-driven CO2 rises in previous decades.

While people sweltered, so did the famous Great Barrier Reef, which suffered a “catastrophic die-off” of corals in 2016. The hot March weather that caused it was made at least 175 times more likely by the human influence on the climate.

The “biggest tragedy we have ever seen”, was how the South African president, Cyril Ramaphosa, described floods in April 2022 that killed many hundreds of people and led to the declaration of a national state of disaster. Global heating made them twice as likely and more intense. Drought has also been exacerbated, with the high-profile “day zero” event in Cape Town in 2018 the result of an exceptionally dry three years – a pattern made “five to six times more likely” by global heating.

The rest of Africa has been poorly studied. But global heating played a significant role in the 2015 drought in Ethiopia, the worst in decades, affecting nearly 10 million people and killing crops and livestock. In Lesotho, global heating was a “critical driver” of a food crisis that gripped the nation in 2007.

Van Aalst said it is vital to remember that these climate-driven events do not act alone but compound other problems. “For instance, there is terrible hunger in the Horn of Africa, with literally thousands of people dying right now and the potential for hundreds of thousands more,” he said. “That is partly drought and other climate-related hazards – they’ve had floods and locust infestations as well.” But the extreme weather had intensified the problems caused by conflicts, a Covid-related rise in extreme poverty and high food prices due to the war in Ukraine, he said.

Not all extreme weather events analysed find an influence from global heating. But these studies are revealing too, said Otto, in highlighting the depth of existing fragility. The recent famine in Madagascar was the result of poverty and overreliance on annual rains, not global heating, research found. “This showed just how much there is to do to even be resilient in the face of the current climate that we have,” let alone a worsening one, Otto said.

Latin America

On 27 May this year in north-east Brazil, 22 days’ worth of rain fell in 24 hours. It was part of a week of downpours that led to catastrophic floods and landslides, killing at least 133 people and displacing tens of thousands more. A rapid assessment found global heating was at least partly responsible.

But few other attribution studies have been done in Latin America, home to 650 million people. One found the fingerprints of global heating on a severe drought in the southern Amazon in 2010. The subsequent die-off of trees, and stunted growth of others, resulted in 4bn more tonnes of CO2 in the atmosphere, roughly equivalent to the annual emissions of the European Union.

Even more temperate parts of South America have been affected. In December 2013, Argentina endured a heatwave made five times more likely by global heating, and in 2017 major floods in Uruguay were made more likely by the same factor.

Known unknowns
The scarcity of studies in the global south worries scientists. “It’s a huge concern and is adding to the injustice of climate change,” said Van Aalst. “The people that have contributed the least to it are hit the hardest and we can’t even tell how bad it really is.”

The lack of knowledge is preventing people from finding the best ways to deal with the impacts, says Otto. “Attribution studies are not just about distilling the role of climate change but about trying to disentangle drivers of disasters.” The problem is the lack of local scientific expertise and funding – most researchers work on attribution studies as volunteers.

“Without crucial support for global south-based research, we will be forgotten once again,” said Tan.

Long tail
The heaviest footprint of the climate crisis on human suffering has been found in recent events, but global heating has been hurting us for many years. There are traces of its influence on the heatwaves that caused the Dust Bowl in the US in the mid-1930s. The starving families forced to leave their homes, immortalised in John Steinbeck’s novel The Grapes of Wrath, are mirrored by those enduring heat, drought and hunger today.

A global study of hot weather events since 1900 also found “a significant human contribution to the probability of record‐breaking global temperature events as early as the 1930s”.

More than 20 years ago, before many of today’s youth climate strikers were born, Australia’s “millennium drought” was “partially attributable to anthropogenic greenhouse warming”. In England, two-thirds of the autumn floods in 2000 were made 90% more likely by global heating. And researchers now estimate that flood heights from Hurricane Katrina, which hit New Orleans in 2005, would have been 15-60% lower without global heating.

The future in our hands
The science of attribution has delivered a bleak but undeniable picture of how global heating is already bringing death and destruction. But what about the future?

“This is what a feverish Earth looks today,” said Bill McKibben, a climate author and campaigner. “The fact that we’re currently headed for 3C of temperature rise, in the light of these studies, is of course terrifying. And 3C won’t be three times as worse – the damage will be exponential, not linear.”

Vicedo-Cabrera was blunt about our prospects. As the world heated up more and urban populations grew, she said, “the number of [heat] deaths will be much larger”.

The lack of attention paid to scientists’ prior warnings frustrates Van Aalst, who is worried by the pace of the escalating damage. “We are seeing worst-case scenarios known about 10 years ago, that we had feared might happen several decades on, already playing out right now,” he said.

Is there any reason for hope? Perhaps the world will finally realise that acting now is far cheaper than not. “The impacts are so much more expensive than anything we would do to mitigate them,” said Otto.

Attribution studies might also help accelerate the vital funds needed by poorer nations to rebuild after disasters. “They prove that specific extreme weather events, whose damage we know the costs of, were caused by the climate crisis,” said Tan.

Figueres remains stubbornly optimistic. “We are not doomed to a continuation of this madness. We – each of us – still hold the pen that will write the future. Collectively, we have the capacity to make the extraordinary changes we need in order to course correct.”

“It is precisely at this late hour, when for many the darkness is at its most intense, we must find the strength to stand up in the firm conviction that this challenge is as daunting as it is conquerable, and that we can sprint toward the light,” she added.

In the grip of the Dust Bowl, Steinbeck’s character Ma also understood that the future was yet to be written. “Up ahead they’s a thousan’ lives we might live,” she said, “but when it comes it’ll on’y be one.”

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