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.



A nerdy scientist’s assessment of risk – Tornadoes vs. Earthquakes

Tornado Risk map - Dakotas

Tornado risk map from the National Weather Service for July 17th, 2015. Sioux Falls was squarely within the 2% zone, meaning there was a 2% chance of a tornado being seen somewhere within 25 miles of your location. Somehow…we all survived.

While at a conference for work in Portland last week, my colleague and I had a nice supper with two USGS colleagues who work in Menlo Park, California and Seattle, Washington, respectively.  We had relayed the news that the night before, there was storm damage in the area, with straight line winds and tornadoes both causing damage.  The West Coast colleagues…oh…let’s just call them “Ben” and “Tamara”…were flabbergasted that we’d want to live in an area so prone to devastating storms.

Tonight, the National Weather Service put out the map I’m showing here, noting that parts of South Dakota had either a 5% or 2% chance of a tornado hitting somewhere within 25 miles of your location. Let’s do the math!  What are the odds of a tornado hitting YOUR exact location on a night like this, when tornadoes were indeed spotted?

An area with a radius of 25 miles is over 54 billion square feet of territory. What are the odds of a tornado hitting your bit of territory, with a 2% chance of one being seen somewhere in this area? The average tornado path is 4 miles, or 21,120 feet. Average width is 500 feet. The average damage path is 10.5 million square feet. Even if you’re in the highest probability area, 5% chance of one being seen relatively near, the chances of one hitting YOUR chunk of territory…0.0010%. For the 2% chance of a tornado near you, the odds are 0.0004% it will strike your exact location.

Without Warning - Oregon Cascadia earthquake Comic

An actual comic-like booklet put out by the Oregon Office of Emergency Management. Yes, West Coasters…you’re in imminent danger of being swallowed whole by a massive earthquake. Tornadoes in the Plains? They’re nothing in comparison.

Just a guess…but we probably have chances similar to this only like 4-5 times a year. If you just use the same strike probability assumptions, you thus only have, likely at absolute most, a 0.0050% chance of a tornado hitting your location in a given year.

That’s an average of about one hit on your exact location every 20,000 years. Most tornadoes are weak F0 or F1, so even a hit might not be that bad.

Now, let’s reconsider the situation for my colleagues living in California and Seattle.  This week the New Yorker ran a story about the upcoming massive Cascadia subduction zone earthquake that could hit, The story said on average, something similar to the massive 1700 earthquake thought to have hit the area occurs about once every 250 years.

Put it all together, and Seattle is 80X as likely to get walloped with a 9.0 earthquake as Sioux Falls is to get a direct hit from a tornado, and even a direct tornado hit in Sioux Falls is likely to be far, far, less damaging than any earthquake.

You are welcome, West Coast storm-haters.  I hope I have reassured you that is once again safe to visit us in stormy Sioux Falls.  🙂

Losing habitat on the Plains

Grasslands - South Dakota

A gravel road and vast grasslands…one of my favorite types of areas to not only bird, but just to experience. It’s becoming a rarer and rarer sight with all the recent cropland expansion in eastern and central South Dakota.

I ran across (yet another) story this morning discussing the huge loss of habitat in the northern Great Plains over the last few years.  It’s not exactly “news” to anyone who has lives here and has paid attention.  A bit of background…in 2007, Congress passed the “Energy Independence and Security Act”.  It was a huge energy bill, with many components. One of which actually was a huge boon to my work at USGS EROS, as we became part of a huge project to look at the potential for sequestering carbon through land use practices.

However, another component is a renewable fuels standard (RFS), with hard mandates for increased use of biofuels by 2022.  In recent years the price of corn has gone up substantially, in no small part due to the RFS.  The result? Massive loss of grassland in my part of the world, with the Dakotas being hit especially hard.

It’s obvious everywhere I bird, both in eastern South Dakota (which has traditionally been a stronghold of corn production), and now increasingly in central South Dakota.  In eastern South Dakota where I live, the only remaining grasslands are 1) those that are on hilly or very rocky ground, areas too difficult to farm, or 2) individual fields that are enrolled in the Conservation Reserve Program (CRP).  CRP provides payments for farmers to keep land in a grassland cover around here, but those payments can’t compete with the profits that can be made by putting arable land into corn production.  I can point to numerous individual fields just on my drive to work that used to be CRP, and had been grassland ever since I moved here over 20 years ago, that have been plowed under and converted to cropland in just the last few years.

The further west you go in the state, the more iffy a proposition it is to grow dryland corn.  The Missouri River dividing the state into “East River” and “West River” used to be a rough dividing line on where corn was grown. Rainfall in South Dakota is a gradient from west to east, with precipitation dropping as you move westward in the state.  One of my favorite birding locations in the winter is around the Presho area. It’s an area with a lot of grasslands and a lot of pheasants (and presumably voles and mice), creatures that attract a lot of winter raptors like Rough-legged Hawks, Ferruginous Hawks, and even the occasional Gyrfalcon or Snowy Owl.  As a drier area than eastern South Dakota, cropland used to be limited to wheat, some sorghum, and sunflowers.  Not any more, as you’re starting to see farmers attempt to grow dryland corn even there.

It’s not just the conversion of complete, large fields from grassland to cropland that you’re seeing, it’s land management practices and micro-scale habitat loss.  From a land management standpoint, the other business that’s booming right now in the Dakotas is the installation of drain tile, underground piping that efficiently drains the land and allows farmers to utilize areas that once tended to collect too much water for cultivation.  One of my favorite little birding spots on my drive to work is now gone, thanks to drain tiling.  It was a low spot along a little drainage way, a moist area that had a grassland and some scattered cattails.  That area was drain tiled and is now a corn field.  From the micro-habitat side, farmers are also ripping out vegetation along fencerows and shelterbelts, trying to squeeze out every acre they can as crop prices are high.

To be frank, it’s damned depressing sometimes to drive around birding, seeing some of your favorite remaining grassland habitats being actively plowed under.  It’s a level of land-use conversion in the northern Great Plains that hasn’t been seen in many decades.

Especially as a father, I can’t help but think “when does it end”?  When do people stop thinking about MONEY, and their short-term well-being, and when do they actually start worrying about their CHILDREN’s future? It’s not just habitat loss, it’s sabotage of the very resources we need to survive.  Increased agricultural land use, drain tiling existing land, and increased fertilizer use as farmers try to bypass crop rotation and plant exclusively corn…all are pumping up nitrate and other pollutant levels in the very water supplies we depend upon to survive.

I tell myself, that just as with the inexorable spread of urban areas across the world, it can’t continue forever, right?  At some point, it has to stop, right?  The only problem is that human beings are too short-sighted to set that “limit” of when we stop degrading and destroying habitat and the resources we depend upon.  What’s going to eventually make it “stop” is ecological disaster…

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