The Waggonwaybreen glacier in Svalbard. Photo: Andreas Weith
As can be seen above, the Waggonwaybreen glacier in Svalbard, Norway, has retreated substantially since 1900. Svalbard’s glaciers are not only retreating, they are also losing about two feet of their thickness each year. Glaciers around the world have retreated at unprecedented rates and some have disappeared altogether. The melting of glaciers will affect people around the world, their drinking water supplies, water needed to grow food and supply energy, as well as global sea levels.
The Intergovernmental Panel on Climate Change estimates that around the world glaciers (excluding the Greenland and Antarctic ice sheets) will decrease in volume between 15 to 55 percent by 2100 even if we are able to limit global warming to under 2˚C; they could shrink up to 85 percent if warming increases much more.
In Earth’s history, there have been at least five major ice ages, when long-term cooling of the planet resulted in the expansion of ice sheets and glaciers. Past ice ages have been naturally set off by a numerous factors, most importantly, changes in the Earth’s orbit around the sun (Milankovitch cycles) and shifting tectonic plate movements that affect wind and ocean currents. The mixture of gases in the atmosphere (such as carbon dioxide and methane) as well as solar and volcanic activity are also contributing factors. Today we are in a warm interval—an interglacial—between ice ages….
Region could lose 30 percent of the snowpack it relies on for irrigation and drinking water—and potentially as much as 60 percent—over the next 30 years
Losses ahead could put farms, energy and drinking water at risk, a new study suggests
By Bob Berwyn, InsideClimate News Apr 27, 2017
The American West has already lost between 10 and 20 percent of its mountain snowpack since the early 1980s, and climate change is partly to blame, new research shows. If greenhouse gas emissions are not curtailed, the region could lose 30 percent of the snowpack it relies on for irrigation and drinking water—and potentially as much as 60 percent—over the next 30 years, the authors write.
The loss can’t be explained by natural climate variations alone, however it is consistent with model simulations that include both natural and human-caused changes, the study says. “These results add to the evidence of a human influence on climate that will have severe impacts on our water supply,” said Benjamin Santer, a Lawrence Livermore National Laboratory climate scientist and a co-author of the paper, published last week in Nature Communications….
Reduced seasonal flooding of wetlands and farm fields in California’s Sacramento Valley threatens a key stopover site for migratory shorebirds, a new study shows. Landsat satellite images reveal that flooded habitat is most limited during peak spring migration when the birds urgently need resting and feeding sites. Near the peak of migration, an area of seasonally flooded land twice the size of Washington, D.C. has been lost since 1983….
The researchers’ analysis of historical biweekly NASA Landsat satellite images of the valley reveals that flooded habitat near the peak time of spring migration has shrunk by more than twice the size of Washington, D.C. over the last 30 years.
“On average, we’re losing an area about four times the size of Central Park each year, during a critical window of time in late March,” said Danica Schaffer-Smith, a doctoral student at Duke’s Nicholas School of the Environment, who conducted the study with researchers from the nonprofit Point Blue Conservation Science.
More than half of all shorebird species in the Western hemisphere are now in decline, Schaffer-Smith noted….
…During the worst of the recent drought years, conservation organizations [The Nature Conservancy, Point Blue Conservation Science, CA Rice Commission, Cornell Lab of Ornithology and others] joined forces to launch BirdReturns, a payment-for-services program that compensated farmers for flooding their fields to provide additional habitat for birds, Schaffer-Smith said. The new study’s findings could help guide the future timing and location of such initiatives.
“Years of drought have heightened scrutiny of water use in California to the point that even rice farmers have begun to explore a switch to drip irrigation to conserve water, but these fields provide important habitat where wetlands have been lost,” she said. Schaffer-Smith and her colleagues published their peer-reviewed paper this month in the journal Remote Sensing of Environment. The study is freely available online through May 3, 2017.
“Satellite imagery can help us get the biggest bang for our buck by targeting conservation initiatives in a specific window of time at key locations,” she said. “Landsat is the longest running Earth observation satellite system we have, and free access to this data enables researchers to look at the effects of seasonality, climate cycles, and long-term trends in land-use change.”
Danica Schaffer-Smith, Jennifer J. Swenson, Blake Barbaree, Matthew E. Reiter. Three decades of Landsat-derived spring surface water dynamics in an agricultural wetland mosaic; Implications for migratory shorebirds. Remote Sensing of Environment, 2017; 193: 180 DOI: 10.1016/j.rse.2017.02.016
Note: Dr. Matt Reiter is a Point Blue Quantitative Ecologist and Blake Barbaree is a Point Blue Avian Habitat Ecologist. Danica is supported by a PhD fellowship from NASA that Dr. Matt Reiter helped her with in early 2013.
Healthy Soils Program funded after multiple years of advocacy by CalCAN and our partners. $7.5 million will be spent in 2017 to reward farmers and ranchers for increasing carbon stores in their soils and reducing greenhouse gas emissions overall. As the program is designed and implemented, CalCAN will continue to provide input aimed at maximizing its effectiveness, reach and accessibility to a diversity of growers.
19,000 acres saved + 47 billion vehicle miles eliminated, thanks to a $37 million investment by the Sustainable Agricultural Lands Conservation Program (SALC). CalCAN will provide input on an expected 2017 request for proposals and argue for funding sufficient to meet the demand.
…Upending a fragile, decades-long balance between human needs and the environment, Congress passed a wide-ranging water bill last weekend that is likely to result in greater pumping of Northern California water to farms and cities in the San Joaquin Valley and Southern California. The bill, co-authored by Sen. Dianne Feinstein, D-Calif., passed with bipartisan support in both houses of Congress, despite furious opposition from Feinstein’s longtime Senate ally, fellow Democrat Barbara Boxer….
…If Obama signs the bill, which is no sure thing, it could put the federal government on a collision course with California regulators. The state has strong laws in place to protect endangered species and Delta water quality. The State Water Resources Control Board, which has broad authority over the allocation of water coursing through the Delta, already has begun updating its standards for water quality and restricting the amount of river flows that can get pumped south….
…A White House spokesman said last week that Obama has concerns about the language regarding Delta pumping and some other sections in the bill. But the bill also has popular provisions – such as $170 million to address the crippled drinking-water system in Flint, Mich. – that would be sacrificed if Obama issues a veto.
Along with the pumping provisions, the bill would funnel money into an array of California water projects. Among them: $415 million for watershed restoration and other environmental aid for Lake Tahoe; up to $335 million for two proposed reservoirs in California, including the Sites reservoir north of Sacramento; $880 million for flood-control projects on the American and Sacramento rivers in Sacramento; and $780 million for flood-control projects in West Sacramento….
Long-term experiment in Yosemite shows managing fires can help make forest more resilient to fire
October 24, 2016 UC Berkeley ScienceDaily
An unprecedented 40-year experiment in a 40,000-acre valley of Yosemite National Park strongly supports the idea that managing fire, rather than suppressing it, makes wilderness areas more resilient to fire, with the added benefit of increased water availability and resistance to drought….
…”When fire is not suppressed, you get all these benefits: increased stream flow, increased downstream water availability, increased soil moisture, which improves habitat for the plants within the watershed. And it increases the drought resistance of the remaining trees and also increases the fire resilience because you have created these natural firebreaks,” said Gabrielle Boisramé, a graduate student in UC Berkeley’s Department of Civil and Environmental Engineering and first author of the study….
…”We know that forests are deep-rooted and that they have a large leaf area, which means they are both thirsty and able to get to water resources,” Thompson said. “So if fire removes 20 percent of that demand from the landscape, that frees up some of the water to do different things, from recharging groundwater resources to supporting different kinds of vegetation, and it could start to move into the surface water supplies as stream flow.”…
Gabrielle Boisramé, Sally Thompson, Brandon Collins, Scott Stephens. Managed Wildfire Effects on Forest Resilience and Water in the Sierra Nevada. Ecosystems, 2016; DOI: 10.1007/s10021-016-0048-1
Sierra Nevada forests are denser than they once were, potentially reducing the amount of runoff that reaches California’s reservoirs. (Dan Brekke/KQED)
With California’s reservoir levels dropping, just about everyone is wishing the state had gotten more water this year. That doesn’t just depend on the weather, according to a team of scientists. Sierra Nevada forests play a big role in the state’s water supply. Just like crops, trees consume water. And Sierra Nevada forests are denser than they once were after decades of fire suppression. That could be reducing the amount of runoff coming from the snowpack — runoff that provides water for most of the state.
“We call the Sierra Nevada our water towers for California,” says Roger Bales, a hydrologist with UC Merced. “About 60 percent of our consumable water comes from the Sierra Nevada.”
Bales is working in a pine forest about 20 miles west of Lake Tahoe, to understand the balance between and trees and runoff. His team has installed hundreds of sensors in the American River basin to record snow depth and soil moisture.
“The snowmelt really enters the soil,” he says, “and flows downslope to the nearest stream channel.”
When trees use water through the process of evapotranspiration, it doesn’t run off into rivers and reservoirs.
“That water travels up the tree trunk and then goes out through the leaves to the atmosphere,” Bales says. And there are a lot more trees using water today than there once were.
Frequent, low-intensity fires once cleared out small trees and maintained spaces in the forest. Decades of suppressing fires has allowed the forest to fill in.
“You go back about 100-to-150 years and the forest data show us there were maybe only half as many trees here,” Bales says.
The snowpack is also less stable in a dense forest. The snow gets stuck in the trees’ branches before reaching the ground and evaporates faster because it’s more susceptible to sun and wind.
Because these changes have happened over millions of acres of forest, Bales says it’s led researchers to a basic question:
“If there were half as many trees, would there be more runoff?” he asks.
The research points to yes, he says — potentially a lot more.
“Is it 20 percent, 30 percent or 40 percent?” Bales says. “We’re sort of in that range. But that’s a hypothesis. Our back-of-the-envelope calculations suggest that you could get anywhere from half a million to a million acre-feet additional water out of the Sierra Nevada.”
A million acre-feet of water is enough to supply two million households in California for a year — an amount that could make a big difference during a drought.
Managing Overgrown Forests
“I think the water piece is really huge,” says Scott Stephens, professor of fire science at UC Berkeley. “I think it’s under-appreciated but it’s massive.”
Stephens has found similar results in the Illilouette Creek basin in Yosemite National Park. About 40 fires have been allowed to burn there over several decades, reducing the number of trees per acre.
“It looks like there’s 20 percent more surface water leaving the streams in that area since the fire program began in the mid-1970s,” he says.
The widely spaced trees also make the forest more resistant to high-severity fire.
“I call it a potential win-win,” Stephens says. “It’s a win from a fire standpoint to have more resilient forests and also maybe a win in terms of being able to provide a critical resource for California, which is water.”
But leaving naturally caused fires to burn over large areas of the Sierra Nevada is tricky, he says, especially near houses and communities.
“Letting fire work in those lands is risky,” Stephens says. “Sometimes it’s going to go as expected and once in a while it goes wrong.”
Another option is to allow timber companies to cut small trees, thinning the forest. It’s commonly done where roads already exist, but can be prohibitively expensive in remote areas and often faces environmental opposition.
Climate change could make the problem even worse. A recent study from UC Irvine found California’s forests will be using even more water by the end of the century, because warming temperatures will make the growing season longer. Runoff could drop by as much as 26 percent.
“If we don’t act today, our grandkids’ grandkids are going to have so few options,” Stephens says. “It’s going to be warmer. It’s going to be more difficult to do this work and they’re going to be basically chasing their tails.”
Stephens says the good news is that California water districts are joining the conversation about how to manage forests. While it didn’t used to be on their radar, the connection between trees and our drinking water is becoming hard to ignore…