Joe Romm had a good piece September on the drought coming to North America and what to expect by way of immigration from the even more devastated Central America. That was a Sept 8 article to which I’ve added quotes from research cited:
http://thinkprogress.org/climate/2015/09/08/3699165/refugees-dust-bowl-mexico/http://www.earthinstitute.columbia.edu/articles/view/3232http://advances.sciencemag.org/content/1/1/e1400082?During the U.S. Dust-Bowl era, some 3.5 million people fled the region. As I noted in “The Next Dust Bowl,” a 2011 Nature article reviewing the literature, “Human adaptation to prolonged, extreme drought is difficult or impossible. Historically, the primary adaptation to dust-bowlification has been abandonment; the very word ‘desert’ comes from the Latin desertum for ‘an abandoned place’.”
But what scientists tell us we are doing to our climate will be much worse than the Dust Bowl of the 1930 — worse even than medieval U.S. droughts. Remember, the Dust Bowl itself was mostly contained to the 1930s, whereas multiple studies project that future Dust Bowls will be so-called “mega-droughts” that last for many decades — “at least 30 to 35 years,” according to NASA. Further, the 1930s Dust Bowl was regionally localized. As the NASA map above makes clear, we are on track to Dust-Bowlify much of the U.S. breadbasket and Southwest, and virtually all of Mexico and Central America.
Other recent research makes clear we would also turn large parts of the Amazon, Europe, and Africa into near-permanent dustbowls. And this would be “irreversible” on a timescale of centuries.
How bad were the medieval droughts? “Highly evolved societies collapsed and descended into warfare.” These are civilization-destroying, monster droughts. As the news release notes, one of those droughts “has been tied by some researchers to the decline of the Anasazi or Ancient Pueblo Peoples in the Colorado Plateau in the late 13th century.”
And the post-2050 droughts we are foisting on future generations will be much worse — considerably drier and hotter. The dark brown area in the top chart corresponds roughly to the normal climate becoming “severe drought,” which of course means a great many years will be much drier. And the normal temperature will be some 9°F warmer.
But what of our poorer neighbors to the south? They will engulfed by near-permanent Dust Bowl or severe drought. And of course their coastal areas (and ours) will be trying to “adapt” to sea level rise of perhaps several feet by 2100. Again for all but the wealthiest coastal areas, the primary adaptation strategy will probably be abandonment.
Much of the population of Mexico and Central America — likely over 100 million people (Mexico alone is projected to have a population of 150 million in 2050!) — will be trying to find a place to live that isn’t anywhere near as hot and dry, that has enough fresh water and food to go around. They aren’t going to be looking south.
Now, from a purely moral perspective, if you burn down your neighbor’s house and farm, most people would say you have some obligation to house and feed them. So what should happen if one exceedingly wealthy country is the primary contributor to destroying the entire climate of another (relatively poor) country, which itself contributed only a tiny bit to that climate change? The answer seems straightforward — we do everything possible to help them.
But what will happen in the real world where this process occurs gradually over the coming decades for Mexico and Central America — at the same time United States is dealing with the self-inflicted destruction of its own livable climate?
The situation will be a humanitarian and security disaster of almost unimaginable dimensions compared to the current refugee crisis. As Femia and colleague Caitlin Werrell told Climate Progress, “If we worry about the security implications of refugee and migration flows in the future, we need to think about the problem in terms of prevention.
Much of our knowledge about past droughts comes from extensive study of tree rings conducted by Lamont-Doherty scientist Edward Cook (Benjamin’s father) and others, who in 2009 created the North American Drought Atlas. The atlas recreates the history of drought over the previous 2,005 years, based on hundreds of tree-ring chronologies, gleaned in turn from tens of thousands of tree samples across the United States, Mexico and parts of Canada.
In the Southwest and Central Plains of Western North America, climate change is expected to increase drought severity in the coming decades. These regions nevertheless experienced extended Medieval-era droughts that were more persistent than any historical event, providing crucial targets in the paleoclimate record for benchmarking the severity of future drought risks. We use an empirical drought reconstruction and three soil moisture metrics from 17 state-of-the-art general circulation models to show that these models project significantly drier conditions in the later half of the 21st century compared to the 20th century and earlier paleoclimatic intervals.
Future drought risk will likely exceed even the driest centuries of the Medieval Climate Anomaly (1100–1300 CE) in both moderate (RCP 4.5) and high (RCP 8.5) future emissions scenarios, leading to drought conditions unprecedented during the last thousand years.”
