Year Ends with Wild Weather, Climate Chaos
December 31, 2015
Somehow, “teachable moment” just doesn’t cut it….
The year, expected to be the hottest on record, may be over at midnight Thursday, but the trouble will not be. Rain in the central United States has been so heavy that major floods are beginning along the Mississippi River and are likely to intensify in coming weeks. California may lurch from drought to flood by late winter. Most serious, millions of people could be threatened by a developing food shortage in southern Africa.
Scientists say the most obvious suspect in the turmoil is the climate pattern called El Niño, in which the Pacific Ocean for the last few months has been dumping immense amounts of heat into the atmosphere. Because atmospheric waves can travel thousands of miles, the added heat and accompanying moisture have been playing havoc with the weather in many parts of the world.
But that natural pattern of variability is not the whole story. This El Niño, one of the strongest on record, comes atop a long-term heating of the planet caused by mankind’s emissions of greenhouse gases. A large body of scientific evidence says those emissions are making certain kinds of extremes, such as heavy rainstorms and intense heat waves, more frequent.
Coincidence or not, every kind of trouble that the experts have been warning about for years seems to be occurring at once.
“As scientists, it’s a little humbling that we’ve kind of been saying this for 20 years now, and it’s not until people notice daffodils coming out in December that they start to say, ‘Maybe they’re right,’ ” said Myles R. Allen, a climate scientist at Oxford University in Britain.
Dr. Allen’s group, in collaboration with American and Dutch researchers, recently completed a report calculating that extreme rainstorms in the British Isles in December had become about 40 percent more likely as a consequence of human emissions. That document — inspired by a storm in early December that dumped stupendous rains, including 13 inches on one town in 24 hours — was barely finished when the skies opened up again.
The dramatic storms are ending a year of record-setting weather globally, with July measured as the hottest month ever and 2015 set to be the warmest year.
Up and down the U.S. East Coast, this month will close as the hottest December ever. In much of the Northeast into Canada, temperatures on Christmas rose into the 70s — tricking bushes and trees into bloom in many locations. In the Washington area, forsythia, azaleas and even cherry blossoms were suddenly in full color.
“I see this as a double whammy,” Michael Mann, a professor of meteorology at Penn State University, said in an email. “El Niño . . . is one factor, human-caused climate change and global warming is another. You put the two together, and you get dramatic increases in certain types of extreme weather events.”
A historic and unseasonable flood has begun on the Mississippi River and its tributaries, thanks to heavy rains that fell from Oklahoma to the Ohio Valley during Christmas week. Never before has water this high been observed in winter along the levee system of the river. The Father of Waters began over-topping its levees just north of West Alton, Missouri (population 500) on Tuesday, forcing evacuations. West Alton lies at the confluence of the Missouri and Mississippi Rivers, about 7 miles upriver from St. Louis. The river is still rising at West Alton, and is expected to crest on Thursday morning at the second highest level ever recorded, about 5′ below the disastrous flood of 1993.
On Friday, the massive Mississippi River flood crest will reach St. Louis, bringing the second highest waters levels ever recorded there (flood records extend way back to 1785 in St. Louis.) The three river gauges downstream from St. Louis–at Chester, Cape Girardeau, and Thebes–are expected to see their highest water highest levels ever recorded on Friday and Saturday. The latest flood forecasts for the Mississippi River issued Tuesday evening by NWS River Forecast Center predicted that Thebes would be the last location to see an all-time record crest in this flood; below Thebes, flood crests between the 2nd and 4th highest on record are expected along most of the Mississippi and the lower portions of two main tributaries, the Ohio and Arkansas Rivers.
The wild record storms that battered the UK 2 years ago are turning out to be the new normal.