Weather Woes in September: What's Global Warming Got to Do With It?

September has been a soggy month, with powerful storms and flooding happening all over the world. While scientists can link some of these weather events directly to global warming, it’s still too early to say for sure if climate change is behind this month's unusual rainfall. "We always have extreme weather, but global warming makes them stronger, especially when it comes to rain," said Paulo Ceppi from Imperial College London's Grantham Institute. "That could be why we’re seeing such intense storms in different places around the globe." Some regions have reported record-breaking rainfall levels this month. In central Europe, for example, storm Boris brought the heaviest rains ever recorded, causing a lot of damage to homes and farms. Global warming has doubled the chance of severe four-day downpours since the pre-industrial era, and costs from climate change are getting higher fast.

In Japan's city of Wajima, more than 120 millimeters (4.7 inches) of rain per hour was recorded due to typhoon Yagi on September 21 - that’s the heaviest rainfall since records started in 1929. "It's hard to say if all these weather events around the world at the same time are caused by climate change," said Liz Stephens, science lead at the Red Cross Red Crescent Climate Centre. "But for every degree Celsius of warming, the air can hold seven percent more moisture." With global temperatures on track to go over 1.5 degrees Celsius above pre-industrial times, things could get even wetter. This summer in the Mediterranean was one of the hottest ever, causing a lot of extra evaporation and pumping more water vapor into Europe. If conditions are right, all that moisture can dump in certain places. "Neutral" weather conditions are currently prevailing, meaning neither El Nino nor La Nina is present. The global September update from Copernicus will give us hard data on precipitation levels next month.

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