North American prairies most sensitive to climate change

Nature - Seddon et al. (2016) - Map of vegetation sensitivity

This map from Seddon et al. (2016), just published in Nature, depicts sensitivity to vegetation production as a result of climate change. Red areas represent areas where natural vegetation communities are more likely to be impacted by climate change. With South Dakota, Nebraska, and the rest of the Great Plains in an area of strong temperature and precipitation gradients, we are also in a hot zone in terms of potential impacts of climate change on our ecosystems. Click for a larger view.

Nature this week published a very good paper about ecosystem sensitivity to climate change, with maps that portray ecosystems most likely to be impacted by changes in water availability, changing temperatures, or changes in cloudiness.  One of the paper’s main discussion points is that the heart of North America, irght here in the Great Plains, is one “hotspot” of climate change impacts.  For the general public and news outlets, it’s typically things like sea-level rise, or extreme temperature changes occurring in the Arctic and northern latitudes that tend to get noticed. However, as this study indicates, even here in the Great Plains, ecosystems are in peril due to the effects of climate change.

Given the obvious north-south temperature gradient and the obvious east-west precipitation gradient in the Great Plains, this probably isn’t too surprising.  I grew up in southern Nebraska, and after a (thankfully) short stint in the Washington D.C. area after college, we moved to South Dakota, where we have now been for 24 years.  We are in southern South Dakota, a mere 4-hour drive to where I grew up.  When moving here, in terms of weather, I was expecting similar conditions to how I grew up, given the short distance.  In the summer, that’s largely true, as summer temperatures are more uniform across the Plains, even as you move north and south.  In the winter however, I quickly found out that in just a 200-250 mile distance to the north, temperatures are substantially colder.  We’re having incredibly warm February weather right now (hello climate change!!), with a temp of 54 yesterday in Sioux Falls, South Dakota.  Back in southern Nebraska, a mere 200+ miles away? Temps reached the lower 70s.

The Great Plains are also marked by a very obvious, very strong gradient in precipitation.   There’s a reason the forests of the eastern U.S. pretty much stop once they get to the Great Plains, as precipitation strongly decreases as you move from east to west.  South Dakota itself is a great example, as “East River” (east of the Missouri River) is primarily dryland farming, mostly corn and soybeans.  As you reach the middle part of the state, precipitation is significantly lower, corn and soybeans start to disappear, and you get into the dry grasslands that make up most of “West River” South Dakota.

Nature - Seddon et al. (2016)

This image from the Nature paper shows what’s most likely to impact native ecosystems: 1) Water availability, 2) Temperature increases, or 3) changes in cloudiness. The strong blue shades in the Great Plains indicates that it’s water availability that’s going to strongly impact our ecosystems, due to both precipitation changes and increased evaporation as temperatures rise. Click for a larger view.

In the Great Plains, we are sitting in a strong transition zone, both in terms of temperature and moisture availability. Thus, while most folks may think of the Great Plains as a boring, simple landscape of grass and crops, as this study shows, we’re also an area that’s likely to be hammered by the effects of climate change. The results of the paper show that it’s not necessarily the increased temperatures themselves that are going to strongly affect ecosystems, it’s water availability.  It’s not just how much rain that falls in an area that drives ecosystem and vegetation response, it’s how temperature and precipitation interact to affect overall availability of water resources.  The warmer the temperature, the greater evaporation that occurs, and the less water that’s available for vegetation.  The Nature paper indicates that the ecosystems (natural vegetation) of the Great Plains likely can handle the increased temperature in isolation, but combined changes in precipitation and temperature will result in water availability changes that could dramatically affect natural ecosystems in the region.

There’s no doubt that the quite (politically) conservative Great Plains of the U.S. is a hotbed of climate change denial.  As the results of this paper show, it’s going to be increasingly difficult for Great Plains residents to deny climate change is impacting their region.  I’m almost positive that it’s not the effects on natural vegetation that will “flip the switch” in the minds of current climate change skeptics in the region.  However, as change becomes more and more pronounced, there’s no doubt the economics of the region, particularly the agricultural sector, will be strongly impacted.

Nothing seems to get a man/woman to “believe” than a direct impact on their pocketbook. That impact may be coming much sooner than most in the Great Plains would ever suspect.



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