The worst floods in central Europe in at least two decades, a monstrous hurricane that killed more than 160 people in the US, two days of heavy rain claiming nearly 200 lives in Nepal - just some of extreme weather to hit the globe in September.
Human-induced climate change is making extreme weather events like heatwaves, floods and storms more frequent and deadly, scientists say, and this trend will continue if the world keeps burning fossil fuels.
The intense rain that caused deadly floods that killed at least 26 people in central Europe was made twice as likely and 7 per cent heavier by climate change, according to analysis by World Weather Attribution (WWA), a global team of scientists that examines the role played by climate change in extreme weather.
Scientists say halving planet-heating greenhouse gas emissions by 2030 is crucial to stop temperatures rising by more than 1.5 degrees Celsius (2.7 Fahrenheit), which would unleash more extreme weather and heat.
But the world is well off target and so extreme weather is expected to become more regular and intense.
There will also be an increased likelihood of two extreme events occurring at the same time, creating “unprecedented compound events“, according to the sixth assessment report from the Intergovernmental Panel on Climate Change (IPCC).
So how exactly does climate change make the weather worse?
How does climate change affect weather events?
Even small increases of 0.5°C degrees in global warming can cause significant changes in the weather, according to the IPCC report.
Global warming happens when greenhouse gases from burning fossil fuels are released into the atmosphere where they trap heat, causing the temperature of the air and seas to rise.
The warmer atmosphere causes more moisture to be absorbed in the air, resulting in both warmer and drier conditions and heavier rainfall, Sonia Seneviratne, a lead author of the IPCC report, told Context.
Different weather extremes are affected in various ways.
Heatwaves
The heat trapped in the atmosphere because of greenhouse gases is making temperatures hotter than they would have been without global warming.
Temperatures of 40°C and 50°C are already becoming more frequent across the world, with the last two summers breaking heat records and causing tens of thousands of deaths.
Precipitation
As the atmosphere warms, more water evaporates, increasing the moisture in the air and causing heavier rainfall.
For every degree of warming, extreme daily rainfall can increase by up to 7 per cent, according to the World Meteorological Organization.
Unprecedented rainfall that caused at least 24 deaths in the United Arab Emirates and Oman in April was found to be up to 40 per cent more intense than if it had occurred without the current 1.2°C global warming above pre-industrial levels.
Floods
Between 2000 and 2020, the number of major floods more than doubled, from 1,389 to 3,254, while the incidence of storms grew from 1,457 to 2,034, according to a UN report.
Flooding is caused by increased rainfall from water stored in the atmosphere and rising sea levels. The latter happens when global warming melts ice and warms oceans, causing the water to expand, according to Seneviratne.
Drought
Higher temperatures draw more moisture from the land and dry out the soil. Dry soil cannot absorb rainwater, meaning that it runs off into rivers, increasing the risk of drought, and later floods.
Droughts can also increase temperatures as the air above the ground warms up more quickly, leading to more intense heat, said Seneviratne.
Wildfires
Intense heat and dry land and soil create perfect conditions for wildfires to spread.
A combination of climate change and land-use change are expected to increase the occurrence of extreme wildfires by 14 per cent by 2030 and 50 per cent by the end of the century, according to a report by the UN Environment Programme and non-profit GRID-Arendal.
The destruction of key ecosystems that help to absorb carbon, like peatland and rainforest, will make it harder to slow rising temperatures.
Cyclones, hurricanes and typhoons
Tropical cyclones, like typhoons and hurricanes, are unlikely to occur more frequently because of climate change, but the proportion of extreme ones is rising, according to the IPCC.
Large amounts of water held in the atmosphere and the energy created by the warmer temperatures in the air will make the storms more intense.
How much is extreme weather costing global economies?
Extreme weather and climate-related events caused nearly 12,000 disasters between 1970 and 2021, costing US$4.3 trillion in economic losses, according to the most recent update of The World Meteorological Organization’s Atlas of Mortality and Economic Losses from Weather, Climate and Water-related hazards.
A study published by Nature found that annual gross domestic product could decrease by up to 10 per cent if the world warms by 3°C, owing to the economic losses incurred from climate-related events.
Typhoon Yagi, Asia’s most powerful storm this year, caused over US$3 billion worth of damages in northern Vietnam, devastating export-oriented industrial hubs, destroying factories and facilities, flooding farmland and damaging homes.
Individual households also face long-term economic losses from extreme events through rising home insurance premiums or costs associated with lost work days in order to prepare for, or clean up from, disasters.
Can we predict extreme weather?
Advances in technology, including artificial intelligence, and greater data availability have improved weather forecasts.
Heavy rainfall was predicted several days in advance of September’s floods in Europe, allowing authorities to empty reservoirs, build flood defence walls and warn people of the imminent danger, according to the WWA report.
It said the death toll was lower compared to the 1997 and 2002 floods, pointing to the effectiveness of investments made in forecasting, early warning systems, and preventative actions such as evacuations.
According to the Global Commission on Adaptation, early warning systems - which give public information about extreme weather events before they hit and activate measures to keep people safe - can cut damage by 30 per cent with just 24 hours’ notice.
In 2022, UN Secretary-General António Guterres launched the Early Warnings for All initiative to ensure that everyone is protected from hazardous weather, water, or climate events through early warning systems by the end of 2027.
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