People are starting to notice — locally, nationally and sometimes internationally — the latest “extreme weather” events. I use quotes because while the weather isn’t normal, it is the new normal; not a transitory extreme.
A recent New York times article “Climate Chaos, Across the Map” lays out a some of the big news we’ve heard about; El NiÃ±o.
Scientists say the most obvious suspect in the turmoil is the climate pattern called El NiÃ±o, 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 NiÃ±o, one of the strongest on record, comes atop a long-term heating of the planet caused by mankinds 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.
The effects of El NiÃ±o are not limited to rainfall in places like California.
Matthew Rosencrans, head of forecast operations for the federal governments Climate Prediction Center in College Park, Md., said that the El NiÃ±o was not the only natural factor at work. This winter, a climate pattern called the Arctic Oscillation is also keeping cold air bottled up in the high north, allowing heat and moisture to accumulate in the middle latitudes. That may be a factor in the recent heavy rains in states like Georgia and South Carolina, as well as in some of the other weather extremes, he said.
It’s a system, it all works together. As such, when humans mess with nature, the results are not always predictable or what we expect. The latest flooding along the Mississippi river is a terrific example. In a piece title “Pied Piper of failed river policies saw this flood coming” for the St-Louis Post-Dispatch, Tony Messenger lays out the human causes of flooding.
He starts with arguments made by Bob Criss, a Washington University geology professor.
This is our fault.
The Mississippi River should not be going crazy after three days of rain, Criss told me Wednesday morning.
Here, the Great Flood of 1993 is a good comparison, not because the high-water records are about to be broken, but because that flood was so different.
1993 was a slow-moving monster, Criss said. Water levels built upstream in the Missouri and Mississippi for days and weeks and months, moving slowly to each new city in its path. They behaved, mostly, as big rivers are supposed to, slowly building, taking in massive amounts of water, and searching for flood plain to relieve its swollen banks.
Eventually, relief came, from the rivers perspective at least, when it broke through the Monarch Levee and flooded the Gumbo Bottoms in what is now known as the Chesterfield Valley.
After that flood, a federally commissioned report, led by Gen. Gerald Galloway of the Army Corps of Engineers, suggested massive changes to federal flood policy. Key to the suggestions were the need to allow the Missouri and Mississippi to connect more naturally to their flood plains, which meant reducing development in low-lying areas.
St. Louis, and most of the nation, it seems, didnt listen.
There are many moving pieces that contribute to the changes in our weather and our atmosphere. We need to realize that our attempts to control nature generally have unforeseen consequences and that no matter which way you look at it, the race to reduce contributions to global warming is more important than ever.