Climate change is likely to exacerbate the South Asian monsoon that had swept Pakistan and its floods that caused several months of flooding killed more than 1,000 people and destroyed nearly 2 million houses.
This conclusion is derived from a latest analysis by World Weather Attribution (WWA, World Weather Attribution Organization). WWA is composed of many scientists who use climate models, weather observations and other tools to determine whether global warming increases the possibility and severity of recent extreme weather events.
However, although climate change has had an impact in the floods in Pakistan, scientists are not clear about how much it plays.
evaluating the impact of climate warming on heat waves through the attribution study, as higher average temperatures push up the baseline of such heat events.
This team has accurately calculated the impacts of multiple climate change. For example, how much climate change had last year’s chances of heat from the Pacific Northwest: if there were no human-caused climate change, this situation would have been “at least 150 times less”; this year’s UK heat wave: climate change makes it “10 times more likely”; and extreme weather in Pakistan and India earlier this year was “30 times more likely” due to climate change.
researchers pointed out in a press statement that for climate models, determining the role of global warming in amplifying the entire monsoon season is a difficult problem. WWA attributes uncertainty to widespread changes in long-term rainstorm patterns, natural processes that models may not fully capture, and the changing weather in the region. Indus basin is located on the western edge of the monsoon region in the region, with extreme rainfall trend differences leading to drought in the west and wet in the east, in a sharp contrast.
On the other hand, weather records clearly show that the period of the highest rainfall in the region has become more intense in recent decades, with rainfall increasing by about 75%. Some models found that picking out five of the most rainy days in these two monsoon seasons in these regions, and climate change could increase rainfall by as much as 50% over the past few days.
"So, while it is difficult to give an exact figure to the contribution of climate change, the traces of global warming are obvious," Friederike Otto, senior lecturer in climate science at Imperial College London and one of the leaders of the WWA, said in a statement.
In a scientific paper released recently, the team pointed out that it was the combination of multiple meteorological forces that drive extreme rainfall, including the La Nina phenomenon (which cools the upper seawater while bringing more rain than usual in most of the world), coupled with Pakistan's unusually hot spring and summer, rising temperatures accelerate the melting of thousands of glaciers that supply the Indus River, although it is not clear to what extent this has caused flooding.
Climate scientists have long warned that as global warming, rainfall patterns around the world will become more unstable, making very wet and very dry periods more common. Among other factors, warmer air retains more moisture, sucks moisture away from the soil and plants, and changes the atmospheric pressure system. The UN Climate Group predicts that in the next few decades, South Asian monsoon will become more variable, and its intensity will continue to increase throughout the 21st century.
WWA notes that as temperatures rise, the worst rainfall days in Pakistan may become more extreme. This underscores the need for the country to strengthen its riverbanks, housing and other infrastructure to protect its people, while wealthy countries, most likely the main driver of climate change, should also do their best to help.
Support: Ren
Original text:
https://www.technologyreview.com/2022/09/15/1059558/fingerprints-of-climate-change-are-clear-in-pakistans-devastating-floods/
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