Drier conditions projected to result from climate change in the Southwest will likely reduce perennial vegetation cover and result in increased dust storm activity in the future, according to a new study by scientists with the U.S. Geological Survey and the University of California, Los Angeles.
The research team examined climate, vegetation and soil measurements collected over a 20-year period in Arches and Canyonlands National Parks in southeastern Utah. Long-term data indicated that perennial vegetation in grasslands and some shrublands declined with temperature increases. The study then used these soil and vegetation measurements in a model to project future wind erosion.
That’s from the USGS news release for its Proceedings of the National Academy of Sciences study, “Responses of wind erosion to climate-induced vegetation changes on the Colorado Plateau.”
Dust-Bowlification “” combined with the impact on food insecurity of Dust-Bowlification (and other extreme events) “” is, I believe, the biggest impact that climate change is likely to have on most people for most of this century (until sea level rise gets serious in the latter decades).
If you want to know what a serious dust storm looks like, the place to go is the canary in the coal mine for climate change — Australia. Here’s an amazing video of the great Sydney Dust Storm of September ‘09:
As NASA’s Earth Observatory described the superstorm:
A wall of dust stretched from northern Queensland to the southern tip of eastern Australia on the morning of September 23, 2009, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this image [see amazing photo below]. The dust is thick enough that the land beneath it is not visible. The storm, the worst in 70 years, led to canceled or delayed flights, traffic problems, and health issues, reported the Australian Broadcasting Corporation (ABC) News. The concentration of particles in the air reached 15,000 micrograms per cubic meter in New South Wales during the storm, said ABC News. A normal day sees a particle concentration 10–20 micrograms per cubic meter.
Something to look forward to.
Indeed, the AP reported yesterday:
Dust Bowl states see farms dry up, fires rage
Drought expected to worsen; grass so dry ‘it’s like gasoline’ for wildfires
… Oklahoma was drier in the four months following Thanksgiving than it has been in any similar period since 1921. That’s saying a lot in the state known for the 1930s Dust Bowl, when drought, destructive farming practices and high winds generated severe dust storms that stripped the land of its topsoil.
Neighboring states are in similar shape as the drought stretches from the Louisiana Gulf coast to Colorado, and conditions are getting worse, according to the U.S. Drought Monitor.
The USGS release continues:
The findings strongly suggest that sustained drought conditions across the Southwest will accelerate loss of grasses and some shrubs and increase the likelihood of dust production on disturbed soil surfaces in the future. However, the community of cyanobacteria, mosses and lichens that hold the soil together in many semiarid and arid environments””biological soil crusts””prevented wind erosion from occurring at most sites despite reductions in perennial vegetation.
“Accelerated rates of dust emission from wind erosion have large implications for natural systems and human well-being, so developing a better understanding of how climate change may affect wind erosion in arid landscapes is an important and emerging area of research,” said Seth Munson, a USGS ecologist and the study’s lead author.
Dust carried by the wind has received recent attention because of its far-reaching effects, including the loss of nutrients and water-holding capacity from source landscapes, declines in agricultural productivity and health and safety concerns. Dust is also a contributing factor in speeding up the melting of snow, which affects the timing and magnitude of runoff into streams and rivers.
Peak wind speeds in the Southwest during the study period generated high rates of sediment transport.
The study itself concludes:
Thus the effects of increased temperature on perennial plant cover and the correlation of declining plant cover with increased aeolian flux strongly suggest that sustained drought conditions across the southwest will accelerate the likelihood of dust production in the future on disturbed soil surfaces.
That’s now my new favorite euphemism for a massive dust storm — “increased aeolian flux.”
A number of major recent studies warn that the Southwest (along with many other highly populated parts of the globe) is likely headed toward sustained — if not near permanent — drought and Dust Bowl-like conditions if we stay anywhere near our current emissions path. Regular readers can skip the rest, but I include the review for the sake of completeness and for the do-little crowd.
Here’s what we need to “adapt to”:
- NOAA: Climate change “largely irreversible for 1000 years,” with permanent Dust Bowls in Southwest and around the globe. This January 2009 PNAS paper finds
“¦the climate change that is taking place because of increases in carbon dioxide concentration is largely irreversible for 1,000 years after emissions stop”¦. Among illustrative irreversible impacts that should be expected if atmospheric carbon dioxide concentrations increase from current levels near 385 parts per million by volume (ppmv) to a peak of 450–600 ppmv over the coming century are irreversible dry-season rainfall reductions in several regions comparable to those of the “dust bowl” era
The irreversible precipitation changes hit the U.S. Southwest, Southeast Asia, Eastern South America, Western Australia, Southern Europe, Southern Africa, and northern Africa.
Note also that this is only 450 to 600 ppm. We’re on track for 800 to 1000 ppm this century on our current emissions path “” a path we are sure to stay on if we listen to the do-little we-can-adapt crowd (see “Our hellish future: Definitive NOAA-led report on U.S. climate impacts warns of scorching 9 to 11°F warming over most of inland U.S. by 2090 with Kansas above 90°F some 120 days a year “” and that isn’t the worst case, it’s business as usual!” and M.I.T. doubles its 2095 warming projection to 10°F “” with 866 ppm and Arctic warming of 20°F).
- Back in October, the National Center for Atmospheric Research published a complete literature review, “Drought under global warming: a review,” (See NCAR analysis warns we risk multiple, devastating global droughts even on moderate emissions path). That study makes clear that Dust-Bowlification may be the impact of human-caused climate change that hits the most people by mid-century, as the figure below suggests (click to enlarge, “a reading of -4 or below is considered extreme drought”):
The PDSI [Palmer Drought Severity Index] in the Great Plains during the Dust Bowl apparently spiked very briefly to -6, but otherwise rarely exceeded -3 for the decade (see here).
The large-scale pattern shown in Figure 11 [of which the figure above is part] appears to be a robust response to increased GHGs. This is very alarming because if the drying is anything resembling Figure 11, a very large population will be severely affected in the coming decades over the whole United States, southern Europe, Southeast Asia, Brazil, Chile, Australia, and most of Africa.
The National Center for Atmospheric Research notes “By the end of the century, many populated areas, including parts of the United States, could face readings in the range of -8 to -10, and much of the Mediterranean could fall to -15 to -20. Such readings would be almost unprecedented.”
For the record, the NCAR study merely models the IPCC’s “moderate” A1B scenario “” atmospheric concentrations of CO2 around 520 ppm in 2050 and 700 in 2100. We’re currently on the A1F1 pathway, which would takes us to 1000 ppm by century’s end, but I’m sure with an aggressive program of energy R&D we could keep that to, say 900 ppm.
- The UK Met Office came to a similar view four years ago in their analysis, projecting severe drought over 40% of the Earth’s habited landmass by century’s end (see “The Century of Drought”).
The projection of extended if not endless drought for the US Southwest has been studied a great deal:
- In 2007, Science (subs. req’d) published research that “predicted a permanent drought by 2050 throughout the Southwest” “” levels of aridity comparable to the 1930s Dust Bowl would stretch from Kansas to California. And they were also only looking at a 720 ppm case.
- In December 2008, the Bush Administration quietly released a US Geological Survey stunner: SW faces “permanent drying” by 2050, which found:
The serious hydrological changes and impacts known to have occurred in both historic and prehistoric times over North America reflect large-scale changes in the climate system that can develop in a matter of years and, in the case of the more severe past megadroughts, persist for decades. Such hydrological changes fit the definition of abrupt change because they occur faster than the time scales needed for human and natural systems to adapt, leading to substantial disruptions in those systems. In the Southwest, for example, the models project a permanent drying by the mid-21st century that reaches the level of aridity seen in historical droughts, and a quarter of the projections may reach this level of aridity much earlier.
- U.S. southwest could see a 60-year drought like that of 12th century “” only hotter “” this century:
An unprecedented combination of heat plus decades of drought could be in store for the Southwest sometime this century, suggests new research from a University of Arizona-led team”¦.
“The bottom line is, we could have a Medieval-style drought with even warmer temperatures,” [lead author Connie] Woodhouse said.
- A new Environmental Research Letters article, “Characterizing changes in drought risk for the United States from climate change,” comes to a similar conclusion as the NCAR study, “Drought frequencies and uncertainties in their projection tend to increase considerably over time and show a strong worsening trend along higher greenhouse gas emissions scenarios, suggesting substantial benefits for greenhouse gas emissions reductions.” See especially Figure 4C.
Finally, another 2011 study, “The Last Drop: Climate Change and the Southwest Water Crisis,” that actually looks in some detail at the scientific literature for just one region, finds that drought and reduced precipitation in the U.S. SW alone could cost up to $1 trillion by century’s end.
That’s something for the adapters to plan for and the rest of the world to suffer through if we’re too greedy and ignorant to spend a small fraction of our wealth on mitigation to avoid it.
Here’s one last amazing video of ‘increased aeolian flux’ in Australia: