Extreme rainfall and searing temperatures are set to become more common in the next two decades thanks to climate change, a damning new report warns.
Scientists in Norway estimate that nearly three-quarters of the global population – around 5.6 billion people – will see dramatic changes in dramatic weather conditions unless carbon emissions fall.
The experts found that a large region including Spain, Italy, Morocco, Peru, India, Pakistan and Saudi Arabia are expected to get ‘clear and rapid’ increases in temperature and rainfall.
Even in the most optimistic scenario, more than 1.5 billion people around the world will be affected by unbearable heat, flash floods and more.
Co-author Dr Bjørn Samset told MailOnline: ‘These cuts are also crucial, but for the coming years we are locked into a more extreme future.’
Researchers have found that 70 per cent of the world’s population will face extremely fast changes to temperature and rainfall in a high-emission scenario (right) while 20 per cent will still be affected in a low-emission scenario (left). On this map, darker regions show areas predicted to experience the most rapid change
The researchers – from the CICERO Center for International Climate Research in Oslo – combined four large climate simulations to work out how much peak rainfall and temperature might shift over the next two decades.
While previous studies have looked at how climate change may affect weather patterns at the country level, this paper took a broader perspective.
Lead author Dr Carley Iles says: ‘We focus on regional changes, due to their increased relevance to the experience of people and ecosystems compared with the global mean, and identify regions projected to experience substantial changes in rates.’
Under the high-emission scenario in which little is done to reduce greenhouse gas emissions, this method finds that a large area of the globe will undergo extreme changes.
In this case, regions such as the Mediterranean, Northwestern and Southern America, and Eastern Asia are expected to see ‘sustained, unprecedented rates of change for two or more decades’.
The researchers combined several climate simulations to predict how rainfall and temperature would change in the next 20 years. This method shows that a large area around the equator (highlighted green) will see unprecedented rates of change. This diagram also shows predictions for individual regions in blue for low-emission scenarios and red for high-emissions
Collectively, the regions expected to see rapid changes in extreme weather events will cover 70 per cent of the world’s population (5.6 billion) unless emissions are reduced dramatically.
The UK, along with the rest of Northern Europe, is not expected to see any rapid temperature changes but could see a significant increase in peak rainfall.
However, this paper also suggests that it may be too late to undo some of the consequences of human-caused climate change.
Dr Samset says: ‘The main takeaway is really how quickly weather conditions will change around the world over the coming two decades, regardless of cuts in emissions.’
In the low emissions scenario in which greenhouse gases are cut fast enough to meet the requirements of the Paris Agreement, 20 per cent of the world’s population (1.6 billion) will still be affected.
The researchers were surprised by how similar the high-emission (red) and low-emission (blue) scenarios were. These graphs show the rate of change of annual maximum daily temperature (right) and the amount of rain on the five wettest day period of the year (left)
If emissions are cut, the most dramatic changes will be limited to the Arabian Peninsula and South Asia.
‘Emission cuts work, but the changes we’ve already caused are so strong that they will dominate for a while yet,’ Dr Samset adds.
As the researchers point out, societies and ecosystems can tolerate a certain amount of natural variation when it comes to weather.
Due to cyclical fluctuations in the climate and seasonal patterns like El Niño, peak temperature and rainfall do change over time.
However, when the rate of change exceeds a certain level this can surpass what the natural world and human society can adapt to.
If the world continues to become hotter and wetter at the rate predicted by the researchers, this will increase the likelihood of extreme events.
Rapid changes to maximum daily temperatures make events like the 2021 Pacific Northwest Heatwave (pictured) more likely. Research has shown that this would not have been possible without climate change
The researchers say that many of the changes of climate change cannot now be stopped. This map shows the regions will see rapidly strengthening extreme weather even if the targets of the Paris Climate Agreement are met
For example, in 2021 the US Pacific Northwest experienced a heatwave of unprecedented magnitude which saw many locations break all-time maximum temperature records by more than 5°C (9°F).
Subsequent research has shown that this event would not have been possible were it not for the effects of climate change.
In their new paper, published in Nature Geoscience, the authors warn that the effects of events like this can include death and destruction.
‘Heatwaves may cause heat stress and excess mortality of both people and livestock, stress to ecosystems, reduced agricultural yields, difficulties in cooling power plants, and transport disruption,’ they say.
The regions most likely to be affected are those least equipped to deal with extreme weather. This includes Pakistan which experienced successive drought and flooding in 2022 (pictured)
‘Society seems particularly vulnerable to high rates of change of extremes, especially when multiple hazards increase at once.’
This is particularly worrying since those regions predicted to see the most rapid changes contain low-income countries that are particularly vulnerable to the impacts of extreme weather – for example by having cheap infrastructure.
This paper also found that some of the attempts to combat human impact on the environment may actually exacerbate extreme weather.
For example, in a process called ‘aerosol-induced surface cooling’, pollutants in the air block some of the sunlight that would otherwise reach Earth.
This effect has actually kept global warming somewhat in check over the last 50 to 100 years and has masked some of the worst impacts.
Air pollution reflects sunlight and keeps the surface cool, as cities like Beijing (pictured) clean up pollution the researchers warn that extreme heat conditions become more likely
Falling air pollution in cities like Beijing (illustrated) actually increases the likelihood of localised extreme weather events
As countries take the necessary steps to remove dangerous air pollution, this will allow more radiation to reach the Earth leading to local temperature spikes and particularly wet rainy seasons.
Of course, reducing air pollution is vital for public health – and the researchers aren’t suggesting air pollution shouldn’t be tackled.
But doing so could lead to spikes in extremely hot and wet weather events.
Co-author Dr Laura Wilcox, a meteorologist from the University of Reading, says: ‘Rapid clean-up of air pollution, mostly over Asia, leads to accelerated co-located increases in warm extremes and influences the Asian summer monsoons.’
‘Now, the necessary cleanup may combine with global warming and give very strong changes in extreme conditions over the coming decades.’
Carbon emissions and the greenhouse effect: A primer
The greenhouse effect is the reason our planet is getting too hot to live on.
CO2 released by human activity is accumulating as an ‘insulating blanket’ around the Earth, trapping more of the sun’s heat in our atmosphere.
Without the natural greenhouse effect, heat would pass outwards from the Earth’s surface into space – making it too cold to live. But emissions of gases such as CO2 and methane push the greenhouse effect too far – acting as a blanket that traps heat
CO2 – and other greenhouse gases – are emitted by actions such as burning fossil fuels like coal for energy, burning forests to make way for livestock and
Fertilisers containing nitrogen produce nitrous oxide emissions – another greenhouse gas.
Meanwhile, fluorinated gases are emitted from equipment and products that use these gases.
Such emissions have a very strong warming effect, up to 23,000 times greater than CO2.
Sources: European Commission/BGS/NASA
