PARIS: Floods are tearing a path of destruction around the world, hitting Kenya, submerging Dubai and forcing hundreds of thousands of people to flee their homes from Russia and flee to China, Brazil and Somalia.
While not all are directly attributable to global warming, these events occur in a year of record temperatures, and they do what scientists have been warning for years: climate change is causing extreme weather events. This confirms that it is further promoted.
Climate change is not just about rising temperatures, but the ripple effects of excess heat trapped in the atmosphere and oceans.
The EU’s climate watchdog, Copernicus, said on Wednesday that April broke its own heat record for the 11th month in a row, but ocean temperatures have been off record for even longer.
“Recent extreme precipitation events are consistent with what would be expected in a warming climate,” Sonia Seneviratne, an expert on the UN-commissioned IPCC Scientific Committee, told AFP.
Warmer oceans allow for more evaporation, and warmer air can hold more water vapor.
Scientists also have calculations about this. For every 1 degree rise in temperature, atmospheric moisture increases by 7%.
“This will lead to more intense rainfall events,” Davide Faranda, an extreme weather expert at France’s National Center for Scientific Research (CNRS), told AFP.
In April, Pakistan recorded twice the normal monthly rainfall, with some provinces receiving 437 percent more than average. Meanwhile, the UAE received nearly two years’ worth of rain in one day.
However, this does not mean that every place on earth gets a lot of rain.
Richard Allan from the University of Reading said: “A warm, dry atmosphere is effective at drawing moisture from one region and pumping this extra water into storms elsewhere.”
This will lead to extreme rain and flooding in some regions, but worse heat waves and drought in others, climate scientists told AFP.
Natural climate variations also affect weather and global rainfall patterns.
This includes periodic phenomena such as El Niño, which tend to bring extreme heat and rain, which contributed to the high temperatures seen on land and sea last year.
Although natural variability plays a role, “the observed long-term increase in global heavy rainfall is being driven by anthropogenic climate change,” Seneviratne said.
Carlo Buontempo, director of the Copernicus Institute, said that cycles such as El Niño, which cycle between high and low tides, are the result of excess heat trapped by rising greenhouse gas emissions that could push global temperatures toward new records. “We will continue to push it forward,” he said.
Given the overlapping forces at play, attributing flooding to climate change alone can be difficult and each event must be judged on a case-by-case basis.
But scientists have developed a peer-reviewed method that allows them to quickly compare today’s events with simulations that consider a world without global warming.
For example, World Weather Attribution, the scientists who pioneered this approach, found that last month’s heavy rains in the UAE and Oman were “most likely” exacerbated by global warming from burning fossil fuels. Stated.
Another rapid assessment network, ClimaMeter, uses a different methodology, but said the massive floods in China in April were “likely to have been influenced” by global warming and El Niño. Ta.
Flavio Pons, a climatologist who worked on the China assessment, said that “global warming and natural change can be difficult to disentangle,” and that some weather phenomena are more clear-cut than others. Ta.
However, in the case of Brazil’s devastating floods, ClimaMeter was able to rule out El Niño as a significant factor and point to human-induced climate change as the main cause.
Many of the countries currently experiencing major flooding, such as Burundi, Afghanistan and Somalia, rank among the poorest and have the least capacity to mobilize responses to such disasters.
But the experience in Dubai showed that even wealthy states are not ready, Seneviratne said.
“We know that warmer weather is likely to lead to more severe extreme weather events, but we cannot predict exactly when or where these extreme weather events will occur,” Joel Hirschi of the UK’s National Marine Center told AFP. ” he said.
“Current levels of preparedness for extreme weather events are inadequate…It is cheaper to prepare and invest now than to act later.”
