Green Alpha's Next Economy is pleased to have Dr. Jeff Deems contribute his expert knowledge to our blog. Jeff is a Research Scientist at the NOAA Western Water Assessment and the National Snow and Ice Data Center at the University of Colorado at Boulder.
Jeff's work and that of scientists the world over is, of course, critical to our understanding of the unique global challenges now confronting civilization for the first time in history. Jeff's work with snow, ice, and water is revealing in its own right and also sheds light on how the various approaches we bring to these challenges have to not only be simultaneous but also coordinated.
Our investment thesis at Green Alpha has always been that "complex, global problems require multi-part, diverse solutions." In other words, we've always felt strongly that our portfolios need to include a lot more than wind farms and solar panels. Jeff's essay, encompassing snow, water, development, energy, and policy, provides a compelling exhibit for that thesis. Further, the insight it provides into the mechanics of the systems involved shows why portfolio managers should be using climate science as a key macroeconomic input. If we fail to understand the full nature of our challenges, how can we select the appropriate remedies?
"Dusty Snowpacks Link Water, Energy, Land Management, and Climate Change"
by Dr. Jeff Deems
Municipal water providers, irrigation and reservoir managers, ski resort operators, river runners, and fisheries managers in the western US all depend on mountain snowpacks to provide water resources, recreation opportunities, and ecological and hydropower flows. All these managers closely monitor the accumulating winter snowpack to look for indications of spring and summer runoff to follow. Recent studies give folks in the Colorado River Basin something else to look for as well: dust blown onto the snowpack by strong spring windstorms.
We've all noticed the phenomenon: dark clothing on a sunny day absorbs more solar energy than white clothing. In the same way, dust-covered snow absorbs more sunlight than pure white snow, and thus melts faster -– snow cover in the Upper Colorado River Basin is disappearing on the order of one to two months early, in part depending on the amount of dust. This earlier, faster snowmelt produces earlier and faster river runoff, complicating water management efforts and reducing critical late-summer flows.
Extremely dusty snow surface in the San Juan Mountains of Southwest Colorado, late Spring 2009. The dusty snow absorbs more sunlight than clean snow, causing the snowpack to melt out 1 to 2 months early.
The early melt-off also exposes bare ground and vegetation sooner, increasing the amount of water that evaporates, and decreasing the amount of water that ends up in the Colorado River by an estimated 800,000 acre-feet (An acre-foot is the amount of water required to cover an area about the size of a football field 1 foot deep in water). This is an enormous volume in an already over-allocated system. For reference, 800,000 acre-feet is about 5% of the total water in the Colorado River, twice what Las Vegas uses in a year, or 1.5 years of Los Angeles water use, or half of the US's annual treaty obligation to Mexico!
Though only recently studied in detail, dust has been blowing out of the desert southwest in large amounts since the mid-1800's. While popular images of deserts involve sand dunes and dust storms, land surfaces in the arid Southwest tend to be well-armored against wind erosion until disturbed. Natural biological, physical, and chemical crusts keep the soils in place, but are easily crushed. Destruction of soil crusts began in earnest with the westward expansion of the United States, and the concurrent introduction of large numbers of grazing animals to western public lands. Desert soils with damaged crusts emit up to 500 times more dust than undamaged sites, and we see a 5-fold increase in wind-blown sediment being deposited in Colorado alpine lakes beginning around 1850.
The dust-producing regions of the Colorado Plateau and Great Basin still host a wide array of crust-busters: cattle and sheep grazing, dryland farming, OHV use, and energy exploration and development. Dust emission is also affected by soil moisture and vegetation cover, and is thereby inextricably linked to drought and climate change. Indeed, in 2009 and 2010, with very sparse vegetation cover in the dust source areas, we saw extreme amounts of dust deposited on Colorado snowpacks, resulting in some of the highest snowmelt rates ever recorded in the basin.
In this important phenomenon we see an interaction of a broad array of social, political, technological, and ecological forces. Water availability is critical to all interests in the western US, and dusty snow has been complicating resource management efforts. Livestock grazing disturbs crust and reduces plant cover, and may be a barely sustainable endeavor on arid lands, especially under the specter of a warming and drying climate; but long-standing societal values and subsistence living make cessation of grazing a complex issue. Off-road recreation is a valuable resource for individuals and communities, but how should it be balanced with broader impacts? And increasing energy demands will increase pressure for conventional and renewable energy development in many arid, public lands in the southwestern US.
Energy exploration and development is one of the most interesting pieces of the dust-on-snow puzzle, contributing to crust disturbance and dust production, but also to water demands. Road networks and drill pads used to access natural gas reserves occupy an ever-increasing area, and exploration "thumper" trucks are crisscrossing fragile landscapes. Increased production of biofuel crops leaves soil tilled and vulnerable during the critical spring dust/snowmelt season. Large solar installations frequently call for scraping of wide swaths of desert landscape. Further, it takes water to make energy, and energy to move water to ever expanding populations, resulting in a complex web of energy and water interdependence and climate, drought, dust, and snowmelt feedbacks.
Yet all is not doom and gloom. Soil surfaces have shown the potential to stabilize once the disturbance mechanism is removed. Maintenance of vegetation cover can reduce surface wind speeds and thus dust emission. Increases in energy and water efficiency as well as diverse energy portfolios can reduce the need and demand for expanded fossil fuel exploration and development, and hold the potential to reduce water usage by the energy sector and energy usage by the water sector. Planning can reduce the number of roads and pipelines.
All indicators point to dust reduction as an important management goal, with the potential to effect positive change in a complex system. This will be an interesting field to watch evolve, as science, management, and policy tools are brought to bear.
Links for more information:
CIRES/University of Colorado press release for 2010 Dust on Snow PNAS article:
Recent PNAS special issue on water and climate change in the Southwest:
NOAA Western Water Assessment:
Center for Snow and Avalanche Studies Colorado Dust on Snow Project:
NSF article on Dust on Snow: