As the LA wildfire is on track to be the most devastating blaze ever in Southern California, a timely new study identifies the cause.
Scientists at the University of California Los Angeles (UCLA) have uncovered a global pattern of what they’re calling ‘hydroclimate whiplash’ – rapid swings between intensely wet and dangerously dry weather.After years of severe drought, dozens of ‘atmospheric rivers’ – long, narrow bands of water vapor in the atmosphere – deluged California with record-breaking rain in the winter of 2022-23, the scientists say.
This buried mountain towns in snow, flooding valleys with rain and snow melt, and setting off hundreds of landslides.
Following a second wet winter in southern California in 2023-24, last year brought a record-hot summer and now a record-dry start to the 2025 rainy season, along with ‘tinder-dry’ vegetation that has since burned in a series of damaging wildfires.
‘Los Angeles is burning, and accelerating hydroclimate whiplash is the key climate connection,’ the experts say.
The UCLA team’s study is published in the midst of the devastating LA wildfires, said to be caused by overgrown vegetation, dry conditions and uncharacteristic winds. On the morning of January 7, severe droughts and winds of up to 100 miles per hour whipped up wildfires in the affluent LA suburb of Palisades. Since then, the infernos have killed at least five people, destroyed thousands of homes and forced over 130,000 residents to evacuate.From storms to floods, droughts and wildfires, intense weather is on the rise globally.
Now, this study warns these extreme events are connected, with one leading to another in a jerky ‘whiplash’ fashion.
Climate change is the trigger for weather whiplash, according to the experts – who predict further large increases as global warming continues.The researchers cite multiple whiplash events between 2016 and 2023, including the 2022 South Asian floods and fatal wildfires in Australia five years ago.
They also point to recent turbulent weather events in California, including the wildfires now blazing through Los Angeles, leaving Hollywood stars’ homes razed.
‘Increasing hydroclimate whiplash may turn out to be one of the more universal global changes on a warming Earth,’ said lead study author Dr Daniel Swain, climate scientist at UCLA.
‘The evidence shows that hydroclimate whiplash has already increased due to global warming, and further warming will bring about even larger increases.’
The team point to ‘anthropogenic’ (human-caused) climate change as the cause of accelerating whiplash – including factors such as farming livestock and burning fossil fuels for energy. Weather whiplash events
- Southern Chile and Argentina: Dec 2016-Dec 2017 – wildfire, floods, landslides
- Central America: Nov 2019-Nov 2020 – floods, landslides, crop loss, human displacement
- Northern and Central Europe: Jan 2018-Jan 2019 – floods, extreme heat, crop loss
- Southeast Australia: Dec 2019-Dec 2020 – wildfire, floods
- West Africa: Jun 2020-Sep 2020 – floods, human displacement, disease outbreak
- North-Central USA: Jan 2020-Jan 2021 – floods, crop loss, hydropower loss, wildfire
- Iran, Pakistan and Eastern Arabian Peninsula: May 2022-Aug 2022 – floods, landslides, infrastructure damage
- Southern China: Jun 2022-Sep 2022 – crop loss, hydropower loss
- Pacific Southwest: Oct 2022-Oct 2023 – wildfire, floods, landslides
- East Africa: Sep 2023-Dec 2023 – crop and livestock loss, food shortages, floods
Because warmer air can hold more water, climate change is causing heavier rainfall and extreme floods, leading to landslides on oversaturated hillsides.
But this extra moisture is also increasing the growth of flammable grass in the months leading up to wildfire season, which is usually between June to October.
Extreme dryness and warmth then dries the plants out, making them more susceptible to catching fire.
A lightning strike, or a human-made spark (such as a campfire or lit cigarette) are common causes of wildfires, but it is the dryness of plants that often determines how much a wildfire spreads.
For the study, the scientists reviewed previously-published scientific papers to identify rapid swings between intensely wet and dangerously dry weather.
Dr Swain and colleagues considered hundreds of previous papers for the review, layering their own analysis on top.
They found hydroclimate whiplash has swelled globally by 31 per cent to 66 per cent since the mid-20th century – even more than climate models suggest should have happened.
Further increases in whiplash events are anticipated depending on how much the planet warms. But the researchers predict an increase of 113 per cent over land areas with 3°C of warming (relative to a 1940-1980 reference period).Hydroclimate whiplash is projected to increase most across northern Africa, the Middle East, South Asia, northern Eurasia, the tropical Pacific and the tropical Atlantic, but most other regions will also feel the shift.
The same climate models project that the whiplash will more than double if global temperatures rise 5.4°F (3°C) above pre-industrial levels.
The Paris Agreement – an international agreement to control and limit climate change signed in 2015 – famously aims to keep global temperature increases below 2.7°F (1.5°C).
A key driver of whiplash is the ‘expanding atmospheric sponge’ – the growing ability of the atmosphere to evaporate, absorb and release seven per cent more water for every degree Celsius the planet warms, according to the team.
‘The problem is that the sponge grows exponentially, like compound interest in a bank – the rate of expansion increases with each fraction of a degree of warming,’ Dr Swain said.
In their paper, published today in Nature Reviews, the team predict that ‘historical increases in hydroclimate volatility will continue with ongoing anthropogenic warming’.
‘The less warming there is, the less of an increase in hydroclimate whiplash we’re going to see,’ added Dr Swain.
‘So anything that would reduce the amount of warming from climate change will directly slow or reduce the increase in whiplash.
‘Yet we are currently still on a path to experience between 2 degrees and 3 degrees Celsius of global warming this century.
‘So substantial further increases in whiplash are likely in our future, and we really need to be accounting for this in risk assessments and adaptation activities.’
Unexplained heatwave hotspots are popping up like ‘angry skin blotches’ around the globe – including one over the UK
Heatwaves around the world in recent years have been so intense that they cannot be explained by global warming alone, a 2024 study claims.
Scientists in New York reported that unexplained heatwave ‘hotspots’ are popping up on every continent except Antarctica like ‘giant, angry skin blotches’.
Marked out on a map, these 10 distinct heatwave regions are so extreme, they fall far beyond what any model of global warming can predict or explain.
They are located in central China, Japan and Korea, the Arabian peninsula, eastern Australia and north Africa.
Others include Canada‘s Northwest Territories and its High Arctic islands, northern Greenland, the southern end of South America and scattered patches of Siberia.
There’s even a heatwave ‘hotspot’ over the UK and northwest Europe, leading to lethal summer temperatures in 2022 and 2023.
