Ecology, Climate Change and Related News

Conservation Science for a Healthy Planet

Tag Archive: drought

  1. Changing climate could have devastating impacts on forest carbon storage

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    • mean loss of carbon from drought and fire impacted forests could equal losing 70% of CA’s 2010 total above ground biomass
    • strategies for reducing some fire risk include actively thinning forests to manage tree density and restoring surface fires
    • healthy ecosystems lead to cleaner, better regulated water flow to communities across the western United States
    May 25, 2017  University of New Mexico  full ScienceDaily article here
    Biologists have shown what could be a startling drop in the amount of carbon stored in the Sierra Nevada mountains due to projected climate change and wildfire events.

    ….roughly half of all human-emitted carbon is absorbed by vegetation and the ocean, and is stored through natural processes — something that helps limit our actual carbon impact on the atmosphere. The problem is, as forests begin to change, due to global warming and large scale fires, the amount of forest carbon uptake will decrease, accelerating the amount of human-made carbon making its way into the atmosphere.

    Our simulations in the Sierra Nevada show that the mean amount of carbon loss from the forests under these projections could be as large as 663 teragrams,” said Hurteau. “That’s equal to about 73 percent of the total above ground carbon stock estimated in California vegetation in 2010.”

    …The two factors that influence these findings are changes in climate and the likelihood of large scale forest fires. Because California is experiencing warmer and drier conditions due to global warming, certain tree species are not able to flourish across particular geographic regions like they once were. Less tree growth, means less carbon uptake in forests.

    The study also shows that wildfires will play a big role in the reduction of stored carbon. And while many of these incidents will occur naturally, Hurteau says we are, in part, to blame for their significance….

    …”We’ve been putting out fires for a hundred years, causing tree density to go way up. In the absence of fire that system has a lot more carbon stored in it,” explained Hurteau. “But, when you have these large fire events the amount of carbon stored in the system drops because it kills many of the trees. Whereas, in a forest that’s been maintained by regular forest fires, which is the natural ecological state, your total carbon at any given point in time can be lower but it stays more consistent.”

    …Hurteau says researchers have identified strategies for reducing some of the fire risk by actively thinning forests to manage tree density and restoring surface fires. It’s an idea that seems counterproductive until you consider how volatile these ecosystems are due to the risk of large scale fires that end up destroying hundreds of thousands of acres.

    …He says it’s not only for the benefit of nature but for all of us, since healthy ecosystems lead to cleaner, better regulated water flow to communities across the western United States.

    Shuang Liang, Matthew D. Hurteau, Anthony LeRoy Westerling. Potential decline in carbon carrying capacity under projected climate-wildfire interactions in the Sierra Nevada. Scientific Reports, 2017; 7 (1) DOI: 10.1038/s41598-017-02686-0

  2. Adapting Forests to Climate Change- new UC guide

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    UC helps forest owners adapt to climate change

    By Jeannette E. Warnert April 5, 2017 University of California Division of Agriculture and Natural Resources Blog

    The new publication, Adapting Forests to Climate Change, can be downloaded free from the UC ANR Catalog. It is the 25th in the Forest Stewardship series, developed to help forest landowners in California learn how to manage their land. It was written by Adrienne Marshall, a doctoral student at the University of Idaho; Susie Kocher, UC Cooperative Extension forestry and natural resources advisor; Amber Kerr, postdoctoral scholar with the UC John Muir Institute of the Environment; and Peter Stine, U.S. Forest Service.

    The document provides specific recommendations for care of three common types of forest in California: mixed conifer, oak woodland and coastal redwood forests… see page 12 for specific management recommendations.

  3. Climate change increasingly responsible for record-setting extreme weather events

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    April 25 2017 Stanford University see full ScienceDaily article here

    In the past, scientists typically avoided linking individual weather events to climate change, citing the challenges of teasing apart human influence from the natural variability of the weather. But that is changing.

    …In a new study, published in this week’s issue of Proceedings of the National Academy of Sciences, Diffenbaugh and a group of current and former Stanford colleagues outline a four-step “framework” for testing whether global warming has contributed to record-setting weather events. The new paper is the latest in a burgeoning field of climate science called “extreme event attribution,” which combines statistical analyses of climate observations with increasingly powerful computer models to study the influence of climate change on individual extreme weather

    ….”Our results suggest that the world isn’t quite at the point where every record hot event has a detectable human fingerprint, but we are getting close,” Diffenbaugh said. For the driest and wettest events, the authors found that human influence on the atmosphere has increased the odds across approximately half of the area that has reliable observations.

    ….One high-profile test case was Arctic sea ice, which has declined by around 40 percent during the summer season over the past three decades. When the team members applied their framework to the record-low Arctic sea ice cover observed in September 2012, they found overwhelming statistical evidence that global warming contributed to the severity and probability of the 2012 sea ice measurements. “The trend in the Arctic has been really steep, and our results show that it would have been extremely unlikely to achieve the record-low sea ice extent without global warming,” Diffenbaugh said.

    Noah S. Diffenbaugh, Deepti Singh, Justin S. Mankin, Daniel E. Horton, Daniel L. Swain, Danielle Touma, Allison Charland, Yunjie Liu, Matz Haugen, Michael Tsiang, Bala Rajaratnam. Quantifying the influence of global warming on unprecedented extreme climate events. Proceedings of the National Academy of Sciences, 2017; 201618082 DOI: 10.1073/pnas.1618082114

     

  4. Climate-Smart Land Trusts: Accelerating Nature-Based Solutions to Secure our Future

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    The California Council of Land Trusts hosted the 2017 California Land Conservation Conference from March 7-9, 2017 at UC Davis.

    Ellie Cohen, Point Blue President and CEO was a keynote speaker.  A pdf of Ellie’s presentation can be found here: Accelerating Nature-Based Solutions- Climate-Smart Land Trusts CCLT Keynote March 7 2017

    You can see a pdf of the full program here.

  5. Grasslands may be more sensitive to rising temperatures than precipitation

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    March 8, 2017 0 Comments Fangzhou Liu  Managing Editor of News  Stanford University full article here

    A team of Stanford and Columbia University researchers have found that U.S. grasslands may be more sensitive to atmospheric dryness than rainfall; their study suggests that scientists may have to look more to rising temperatures than precipitation in predicting plants’ response to global warming. Published on March 6 in Nature Geoscience, the researchers’ study examined 33 years of satellite data to understand grassland productivity in dry conditions. The timescale and quantity of data the team examined allows the study to inform predictive models of how environments will respond to droughts — which are likely to become more prevalent with rising temperatures around the globe.  …”U.S. grasslands are way more sensitive to vapor pressure deficit (VPD), which is important. Because VPD is so tightly linked to temperature, we can predict that it’s going to keep going up in the future.”…

    Sensitivity of grassland productivity to aridity controlled by stomatal and xylem regulation

    1. Konings, A. P. Williams & P. Gentine Nature Geoscience (2017) doi:10.1038/ngeo2903

    …We conclude that increases in vapour pressure deficit rather than changes in precipitation—both of which are expected impacts of climate change—will be a dominant influence on future grassland productivity.

  6. What does the new federal water bill mean for California? For one, a big win for farmers

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    December 12, 2016 5:48 PM Sacramento Bee

    Read full article here

    …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….

  7. Pacific Ocean’s response to greenhouse gases could extend California drought for centuries

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    ScienceDaily UCLA September 15, 2016 https://www.sciencedaily.com/releases/2016/09/160915131524.htm

    Clues from prehistoric droughts and arid periods in California show that today’s increasing greenhouse gas levels could lock the state into drought for centuries, according to a study led by UCLA professor Glen MacDonald.

    The study, published today in the Nature journal Scientific Reports, looked at how natural climatic forces contributed to centuries-long and even millennia-long periods of dryness in California during the past 10,000 years. These phenomena — sun spots, a slightly different earth orbit, a decrease in volcanic activity — intermittently warmed the region through a process called radiative forcing, and recently have been joined by a new force: greenhouse gases.

    As long as warming forces like greenhouse gases are present, the resulting radiative forcing can extend drought-like conditions more or less indefinitely, said MacDonald, a distinguished professor of geography and of ecology and evolutionary biology. “Radiative forcing in the past appears to have had catastrophic effects in extending droughts,” said MacDonald, an international authority on drought and climate change.

    “When you have arid periods that persist for 60 years, as we did in the 12th century, or for millennia, as we did from 6,000 to 1,000 B.C., that’s not really a ‘drought.’ That aridity is the new normal.”….

    Prolonged California aridity linked to climate warming and Pacific sea surface temperature
    http://www.nature.com/articles/srep33325

    Glen M. MacDonald et al Scientific Reports 6, Article number: 33325 (2016) doi:10.1038/srep33325 Published on line 15 September 2016

  8. U.S. forests are so full of dead trees that some scientists want to burn them instead of coal

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    By Chris Mooney September 8 2016 Wash Post

    https://www.washingtonpost.com/news/energy-environment/wp/2016/09/08/so-many-u-s-trees-have-died-that-some-scientists-want-to-burn-them-instead-of-coal/?utm_term=.a5b7807304b5

    The state of California, wracked by drought, has 66 million dead trees across its landscape. They’ve been killed by both the drought itself and by voracious bark beetles, and now they’re just sitting there — destined to either decompose, burn in a wildfire, or be incinerated, for safety reasons, by state fire managers before the next blaze comes along.

    And it isn’t just California. Raging bark beetle infestations, fanned by warmer temperatures and droughts, have also struck forests in Colorado, Wyoming, Montana, and Idaho in recent years. “About 100,000 beetle-kill trees fall every day in Wyoming and northern Colorado, to give you an idea of the order of magnitude,” says Erica Belmont, a professor of mechanical engineering at the University of Wyoming.

    Belmont is studying an intriguing solution for what to do with all these dangerous dead trees — namely, burn them for energy. In a recent study in Energy Policy, Belmont and colleague Emily Beagle do the math on whether it would make sense to use the timber in existing coal plants, which can be “co-fired” with wood. In isolation, it probably costs coal plants too much money to go around rounding up dead trees, carting them back, and then burning them — a big endeavor, Belmont explained. But there are sources of possible funds. For instance, the U.S. Forest Service is currently spending considerable money to treat forests and rid them of these dangerous trees — money that, maybe, could be given to the companies that burn them for energy instead, the study suggests.

    Moreover, coal plants are facing strong climate regulations, in the form of the pending Clean Power Plan. In this regulatory context, burning trees that are already destined to decompose, catch fire, or be incinerated — and thus, give off greenhouse gases to the atmosphere no matter what — could conceivably supplant some of coal’s voluminous emissions.

    Large numbers of scientists have loudly protested recent legislative attempts to decree that biomass burning is “carbon neutral” based on the logic that, even though it gives off greenhouse gas emissions just as coal does (releasing the carbon that had been stored in the tree as it grew), future tree regrowth will one day sequester those emissions once again. A leading critique of this assertion is that it takes a long time for a tree to grow back, meaning that the biomass burning is still adding carbon dioxide to the atmosphere for, at least, decades — a time period that can make a real difference for the climate and for climate policy. Moreover, there is not necessarily any guarantee that for every tree chopped down to provide electricity, another corresponding tree will regrow someday. Changing decisions about land use, for instance, could upset that assumption ….

    …”The commonly-made claim that burning wood for energy is ‘carbon neutral’ is at best an exaggeration and at worst completely wrong,” said Phil Duffy, president of the Woods Hole Research Center and a prominent critic of biomass energy, after reviewing the study for the Post. “Because beetle-kill wood will decompose anyway, however, this case comes closer to being carbon neutral than others.”

    But Duffy also added by email that the research may have missed some key points that complicate the analysis, such as the amount of carbon that would be required to transport dead trees to coal plants before they are even burned. He also pointed out by email that “it is not clear if they accounted for the greater emissions from wood versus coal per unit of energy produced.” Ultimately, Duffy suggested, the research might be “pretty overoptimistic about the amount of emissions saved compared to the baseline scenario (letting the wood decompose and burning pure coal).”…

  9. Plants that received extra carbon dioxide didn’t grow more or get greener

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    By Seth Borenstein and Alicia Chang, AP science writers LOS ANGELES — Sep 5, 2016, 3:06 PM ET

    In the course of a 17-year experiment on more than 1 million plants, scientists put future global warming to a real world test — growing California flowers and grasslands with extra heat, carbon dioxide and nitrogen to mimic a not-so-distant, hotter future. The results, simulating a post-2050 world, aren’t pretty. And they contradict those who insist that because plants like carbon dioxide — the main heat-trapping gas spewed by the burning of fossil fuels — climate change isn’t so bad, and will result in a greener Earth. At least in the California ecosystem, the plants that received extra carbon dioxide, as well as those that got extra warmth, didn’t grow more or get greener. They also didn’t remove the pollution and store more of it in the soil, said study author Chris Field, director of the Stanford Woods Institute for the Environment. Plant growth tended to decline with rising temperatures…..

    ….Only the extra nitrogen — a byproduct of diesel engines and ammonia used as fertilizer — made plants greener. Field, whose study appears Monday in the journal Proceedings of the National Academy of Sciences, theorizes that there’s a limit to how much carbon dioxide plants can use. Outside scientists praised the long-running experiment.…”This study clearly demonstrates that as temperatures continue to rise due to climate change, grassland ecosystems will likely not be able to tolerate the higher temperatures and increased drought stress,” Boston University biologist Richard Primack emailed….

    Nonlinear, interacting responses to climate limit grassland production under global change

    http://www.pnas.org/content/early/2016/08/30/1606734113?trendmd_shared=0

    Kai Zhu, doi: 10.1073/pnas.1606734113