|Indian soldiers rescue a man from floodwaters in|
Chennai, India. Photo by R. Snethi Kumar/AP
Extreme flooding there this week has killed at least 270 people, cut off millions from basic services and inundated most of the city, including the airport.
November was Chennai's wettest month on record, wit 47 inches of rain, and another 11 inches opened the month of December, triggering the flooding. Eleven inches in one day is more than the city usually gets in the entire month of December.
Flooding is common around Chennai, but this was by far the worst. Meterologists say a combination of a strong northeast monsoon, caused by the record strong El Nino, combined with record warm temperatures in the Indian Ocean waters, helped trigger the flooding.
Warm ocean water creates more evaporation into the atmosphere, potentially triggering heavier rain than would otherwise occur. Many scientists say climate change is contributing to warmer ocean waters in many parts of the world.
I can't with a straight face blame global warming for the Chennai floods, but it's possible it was one of many contributors. Probably not the main contributor, though.
It's difficult if not impossible to say what role, if any, climate change has on a particular weather event. I can only say global warming increases the liklihood of extreme precipitation in many parts of the world.
|People stuck on or near an overpass in flooded Chennai,|
India. Photo by STRDEL/AFP/Getty Images.
That's not to say the flooding wasn't man-made. The Los Angeles Times says Chennai's network of lakes, rivers, canals, swamps and marshlands that used to absorb rainwater or diverted it into the ocean has been replaced by housing, businesses, malls, parking lots and other development. So the torrential rains couldn't soak into the wetlands, and instead poured through populated areas.
A similar flood in Mumbai in 2005, which killed about 1,000 people, was also blamed on overdevelopment that destroyed wetlands and replaced them with concrete. Again, rainwater could not be absorbed as a result.
Water has receded over the past day in Chennai, but forecasters warn of more downpours there over the next few days.