Ecology, Climate Change and Related News

Conservation Science for a Healthy Planet

Category Archive: Climate Change

  1. Diversity of large animals plays an important role in carbon cycle

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    • We have to maintain the diversity and abundance of animals, especially mammals, in order to ensure a well-functioning carbon cycle and the retention of carbon in soils
    • To increase carbon sequestration, we have to preserve not only high numbers of animals but also many different species

    October 10, 2017 Stanford University read full ScienceDaily article here

    With abundant data on plants, large animals and their activity, and carbon soil levels in the Amazon, research suggests that large animal diversity influences carbon stocks and contributes to climate change mitigation….

    …”It’s not enough to worry about the trees in the world holding carbon. That’s really important but it’s not the whole story,” said Fragoso. “We also have to worry about maintaining the diversity and abundance of animals, especially mammals at this point, in order to ensure a well-functioning carbon cycle and the retention of carbon in soils.”

    Although scientists have long understood that animals — through ingestion, digestion, breathing and decomposition — are part of the carbon cycle, the work, published Oct. 9 in Nature Ecology and Evolution is the first to suggest the importance of animal biodiversity rather than just animal numbers in the carbon cycle.

    If we want to increase carbon sequestration, we have to preserve not only high numbers of animals but also many different species, the authors said.

    …The researchers found that soil had the highest carbon concentrations where they saw the most vertebrate species. When they looked for a mechanism that could explain this relationship, it turned out that the areas with highest animal diversity had the highest frequency of feeding interactions, such as animals preying on other animals or eating fruit, which results in organic material on and in the ground. The researchers suggest that these meal remnants bump up diversity and abundance of soil microbes, which convert the remains into stored carbon

    Mar Sobral, Kirsten M. Silvius, Han Overman, Luiz F. B. Oliveira, Ted K. Rabb, José M. V. Fragoso. Mammal diversity influences the carbon cycle through trophic interactions in the Amazon. Nature Ecology & Evolution, 2017; DOI: 10.1038/s41559-017-0334-0

  2. Herbivores help protect ecosystems from climate change

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    • In the summer, when temperatures were at their warmest in the intertidal zone, biological communities could fare well even if they were heated, but only if limpets were present

    October 11, 2017 University of British Columbia read full ScienceDaily article here

    Plant-eating critters are the key ingredient to helping ecosystems survive global warming, finds new research that offers some hope for a defense strategy against climate change.

    The herbivores created space for other plants and animals to move in and we saw much more diversity and variety in these ecosystems,” said Rebecca Kordas, the lead author of the study who completed this research as a PhD student in zoology at UBC. “We want variety because we found it helps protect the ecosystem when you add a stressor like heat.”

    …The researchers found that in the summer, when temperatures were at their warmest, communities could fare well even if they were heated, but only if limpets were present. “When limpets were part of the community, the effects of warming were less harsh,” she said….

    …The researchers were studying life in the intertidal zone, the area of the shore between the low tide and high tide. This area is home to a community of starfish, anemones, mussels, barnacles and seaweed. As the tide moves in and out, the plants and animals must cope with huge variation in temperature every day, sometimes as much as 20 to 25 degrees Celsius.

    These creatures are already living at their physiological limits, so a two-degree change –– a conservative prediction of the warming expected over the next 80 years or so — can make a big difference,” said Kordas. “When heat waves come through B.C. and the Pacific Northwest, we see mass mortality of numerous intertidal species.”…

    Rebecca L. Kordas, Ian Donohue, Christopher D. G. Harley. Herbivory enables marine communities to resist warming. Science Advances, 2017; 3 (10): e1701349 DOI: 10.1126/sciadv.1701349

  3. Northern California firestorm ‘literally exploded’; 2015 study found warming climate to make “Diablo” offshore winds more frequent and stronger, fueling more destructive fires

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    • years of drought followed by record-breaking rainfall increased fuel load [after a century of fire-suppression combined with inappropriate siting of houses and other built infrastructure]
    • 2015 study found that a warming climate will likely make these “Diablo” offshore winds both more frequent and stronger, fueling potentially destructive fires

    Updated Oct 11 2017  Read full ClimateProgress article here

    …The fires ignited late Sunday night and into Monday morning and have since spread over 50,000 acres across Napa and Sonoma counties, destroying at least 3,500 structures and sending at least 100 to the hospital with injuries ranging from burns to smoke inhalation…

    …Fast-moving winds and low humidity aren’t rare in California, and neither are October wildfires, but it’s likely climate change made these fires even more destructive. After years of historic, prolonged drought, which studies have linked to climate change, California experienced record-setting rains that fueled the growth of grasses and underbrush — young vegetation that dries easily during the summer and is especially susceptible to ignition. Because warmer atmospheric temperatures can hold more water, experts have suggested that the cycle of drought followed by intense precipitation could be linked to climate change.

    Even the state’s characteristic winds — known in the northern part of the state as Diablo Winds and in the southern part of the state as Santa Ana winds — could be getting worse because of climate change. The Santa Ana and Diablo winds occur when high inland pressure pushes air down the sides of mountains (Mt. Diablo in northern California and Mt. Ana in southern California), whipping wind through the canyons and hillsides outside major population centers like Los Angeles and San Francisco. According to a 2015 study lead by researchers at University of California, Los Angles, UC Davis, UC Irvine, and the U.S. Forest Service, a warming climate will likely make these winds both more frequent and stronger, fueling potentially destructive fires….

    ….The National Wildfire Coordinating Group currently lists 179 active wildfire situations throughout much of the Western United States, from Colorado to Washington. The largest active fire in the United States is the Chetco Bar Fire in southern Oregon, which has burned over 191,121 acres and is 97 percent contained. As of October 6, wildfires have burned 8,469,590 acres across the United States — the third largest total acreage burned in the last 10 fire seasons….

  4. Droughts and wildfires in southwest: Global warming is drying up the North American monsoon

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    • North American monsoon, the summer rains that sweep across the southweset US and northwestern Mexico, is not simply delayed; the Southwest faces a dramatic reduction in rainfall

    October 9, 2017 Princeton University read full ScienceDaily article here

    Previous researchers had concluded that global warming was simply delaying the North American monsoon, which brings summer rains to the southwestern US and northwestern Mexico. But a new, high-resolution climate model that corrects for persistent sea surface temperature (SST) biases now accurately reflects current rainfall conditions and demonstrates that the monsoon is not simply delayed, but that the region’s total rainfall is facing a dramatic reduction

    ..most of those droughts are attributed to the change in winter storms, said Pascale. “The storm track is projected to shift northward, so these regions might get less rain in winter, but it was very uncertain what happens to the monsoon, which is the other contributor to the rains of the region. We didn’t know, and it’s crucial to know,” he said…[they quantified] the monsoon response to the doubling of atmospheric carbon dioxide, increased temperatures and other individual changes…

    Salvatore Pascale, William R. Boos, Simona Bordoni, Thomas L. Delworth, Sarah B. Kapnick, Hiroyuki Murakami, Gabriel A. Vecchi, Wei Zhang. Weakening of the North American monsoon with global warming. Nature Climate Change, 2017; DOI: 10.1038/nclimate3412

  5. Scientists develop tool which can predict coastal erosion and recovery in extreme storms

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    October 11, 2017 University of Plymouth read full ScienceDaily article

    Coastal scientists have developed a computerized model which goes some way to answering…how to use existing data to confidently forecast annual coastal erosion and accretion.

    [The] computer model… uses past wave observations and beach assessments to forecast the erosion and/or accretion of beach sediments over the coming year.They believe it could be a sea change for coastal managers, giving them the opportunity to make decisions that could protect communities from severe wave damage… They  have developed a traffic light system based on the severity of approaching storms, which will highlight the level of action required to protect particular beaches…

    Mark A. Davidson, Ian L. Turner, Kristen D. Splinter, Mitchel D. Harley. Annual prediction of shoreline erosion and subsequent recovery. Coastal Engineering, 2017; 130: 14 DOI: 10.1016/j.coastaleng.2017.09.008

  6. Climate change predicted to reduce size, stature of big bluestem grass- dominant Midwest plant

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    • Most of the change was because of alterations in rainfall that are expected to occur across the area, not because of increases in temperature.
    • If smaller forms of the bluestem come to dominate it could cause a fundamental shift in the habitat and ecosystem services prairies provide, such as forage for cattle.
    October 11, 2017 Kansas State University read full ScienceDaily article

    The economically important big bluestem grass — a dominant prairie grass and a major forage grass for cattle — is predicted to reduce its growth and stature by up to 60 percent percent in the next 75 years because of climate change, according to a study involving Kansas State University researchers.

    Big bluestem, or Andropogon gerardii, is a common grass in natural and restored prairies across the central Midwestern region that includes Kansas, Nebraska, Oklahoma, Missouri and Iowa. The grass species is an important component of forage for the region’s livestock industry. It also is commonly used in grassland restoration of prairies across several million acres in the Great Plains region.

    “Our results predict that climate change could greatly impact the tallgrass prairie as we currently know it, reducing forage for cattle in the drier parts of grasslands, in places like Kansas,” Johnson said.

    The research team found that most of the change was because of alterations in rainfall that are expected to occur across the area, not because of increases in temperature. The authors are concerned the dramatic reduction in size of big bluestem foretells a fundamental shift in the nature of the Midwestern grassland ecosystem….

    Adam B. Smith, Jacob Alsdurf, Mary Knapp, Sara G. Baer, Loretta C. Johnso…n. Phenotypic distribution models corroborate species distribution models: A shift in the role and prevalence of a dominant prairie grass in response to climate change. Global Change Biology, 2017; 23 (10): 4365 DOI: 10.1111/gcb.13666

  7. Greenland’s Coasts Are Growing as Seas Rise

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    • Melting glaciers are causing Greenland’s delta regions to expand

    By Chelsea Harvey, ClimateWire on October 5, 2017 see full story here

    …It seems that river deltas on the coast of Greenland are actually growing bigger at a time when many deltas elsewhere around the world—and even elsewhere throughout the Arctic—are eroding away. The finding is all the more surprising considering that Greenland is home to the world’s second-largest ice sheet, whose melting glaciers are among the planet’s biggest potential contributors to future sea-level rise.

    Here’s the surprise: It’s the melting glaciers that are causing these delta regions to expand, scientists say….the researchers note that as glaciers melt, they send fresh water and loose sediment flowing out toward the ocean. The sediment is then deposited along the coastline where the rivers meet the sea, causing the delta to expand outward….

    Mette Bendixen et al. Delta progradation in Greenland driven by increasing glacial mass loss.  Nature 550 October 2017.
     
    Credit: Arterry Getty Images
  8. Carbon feedback from forest soils accelerates global warming

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    • Soil warming stimulates periods of abundant carbon release from the soil to the atmosphere alternating with periods of no detectable loss in soil carbon stores
    • Humans release about 10 billion metric tons (Gt) of carbon into the atmosphere each year and Earth’s soils contain about 3500 billion metric tons (Gt) of carbon which if added to atmosphere could accelerate global warming
    • Over the course of the 26-year experiment (which still continues), the warmed plots lost 17 percent of the carbon that had been stored in organic matter in the top 60 centimeters of soil
    • Study demonstrates value of long term data sets

    October 5, 2017  Marine Biological Laboratory  read full ScienceDaily article here

    After 26 years, the world’s longest-running experiment to discover how warming temperatures affect forest soils has revealed a surprising, cyclical response: Soil warming stimulates periods of abundant carbon release from the soil to the atmosphere alternating with periods of no detectable loss in soil carbon stores. The study indicates that in a warming world, a self-reinforcing and perhaps uncontrollable carbon feedback will occur between forest soils and the climate system, accelerating global warming.

    ….each year, mostly from fossil fuel burning, we are releasing about 10 billion metric tons of carbon into the atmosphere. That’s what’s causing the increase in atmospheric carbon dioxide concentration and global warming. The world’s soils contain about 3,500 billion metric tons of carbon. If a significant amount of that soil carbon is added to the atmosphere, due to microbial activity in warmer soils, that will accelerate the global warming process. And once this self-reinforcing feedback begins, there is no easy way to turn it off. There is no switch to flip.”…

    ….”if the microbes in all landscapes respond to warming in the same way as we’ve observed in mid-latitude forest soils, this self-reinforcing feedback phenomenon will go on for a while and we are not going to be able to turn those microbes off. Of special concern is the big pool of easily decomposed carbon that is frozen in Arctic soils. As those [Arctic] soils thaw out, this feedback phenomenon would be an important component of the climate system, with climate change feeding itself in a warming world….”

    Heated and control plots in a long-term soil warming study at Harvard Forest, Petersham, Mass. Jerry Melillo of the Marine Biological Laboratory, Woods Hole, Mass., and colleagues began the study in 1991.
    Credit: Audrey Barker-Plotkin
    …Melillo and colleagues began this pioneering experiment in 1991 in a deciduous forest stand at the Harvard Forest in Massachusetts. They buried electrical cables in a set of plots and heated the soil 5° C above the ambient temperature of control plots. Over the course of the 26-year experiment (which still continues), the warmed plots lost 17 percent of the carbon that had been stored in organic matter in the top 60 centimeters of soil….
    J. M. Melillo, S. D. Frey, K. M. DeAngelis, W. J. Werner, M. J. Bernard, F. P. Bowles, G. Pold, M. A. Knorr, A. S. Grandy. Long-term pattern and magnitude of soil carbon feedback to the climate system in a warming world. Science, 2017; 358 (6359): 101 DOI: 10.1126/science.aan2874
  9. Risk of sudden reconfiguration of global circulation – Climate may not continue ‘playing nice’

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    Interview with glaciology professor Jorgen Peder Steffensen (see video )

    • The 11,000 years of the interglacial period since the last ice age “has been unreasonably stable. And we don’t know why” or how long that stability may persist.
    • Human activities could be “tipping the climate into an intermediate period of climate changes
    • We can face a climate change that happens just as fast as the financial crisis…In that case, agricultural activity worldwide could be adversely affected … “the weather will change, and it will not change back” quickly.

    Peter Sinclair Tuesday, October 3, 2017 read full Yale Climate Connections article here

    Like “rats inside the experiment,” Neils Bohr Institute glaciology professor Jorgen Peder Steffensen says of us humans when he considers the risks of a sudden reconfiguration of global circulation which could, among other things, cause long-term drying across America’s breadbasket states.

    “That’s going to impact the entire world,” Steffensen cautions in recognizing that the 11,000 years of the interglacial period since the last ice age “has been unreasonably stable. And we don’t know why” or how long that stability may persist.

    Steffensen, in exceptionally eloquent and straightforward language, acknowledges that models consistently point to a gradual global increase in temperatures as a result of the continue widespread combustion of fossil fuels and increased emissions of carbon dioxide. “But that’s assuming the climate plays nice,” he says. “And we actually know from the ice cores that the climate does not play nice all the time.

    Interviewed by Yale Climate Connections regular videographer Peter Sinclair in Kangeraussuaq, Greenland, this past summer, Steffensen, a professor of glaciology, sees an analogy between the continued emissions of greenhouse gases and the rises posed to the U.S. and global economy by the 2006/2007 widespread sales of subprime loans.

    Deeply involved in drilling of ice cores on the Greenland and Antarctic ice sheets since 1980, Steffensen says in this month’s “This is not cool” video that changes in global heat flows have “come about suddenly” in the past and “are reflected, as a mirror image,” in Antarctic ice cores.

    “You see that inside an ice age, the climate is extremely unstable. And you have this sequence of abrupt climate changes that happen, basically, from one year to the next.” He says each cycle lasts “about a couple thousand years…. We had that 26 times in the last ice age.”…

    …He is concerned that human activities could be “tipping the climate into an intermediate period of climate changes…. We can face a climate change that happens just as fast as the financial crisis,” Steffensen says. In that case, agricultural activity worldwide could be adversely affected … “the weather will change, and it will not change back” quickly.

    We don’t know where the threshold is,” Steffensen says of the ongoing human “experiment” with climate change. “But we are rats inside the experiment.”...

  10. Cows may have contributed to recent uptick in atmospheric methane

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    • There has been an alarming uptick in atmospheric methane in recent years, following a flattening of concentrations from 2000 to around 2007
    • Just from livestock methane emissions, study’s revisions resulted in 11 percent more methane in a recent year than previously estimated– not the biggest contributor to the annual methane budget in the atmosphere, but it may be the biggest contributor to increases in the atmospheric budget over recent years

    By Chris Mooney September 29  2017 read full Washington Post article here

    When it comes to climate change, we know where the most important warming agent — carbon dioxide — is coming from….But the second-most potent greenhouse warming agent — the hard-hitting, if short-lived, gas known as methane — presents more of a mystery. There has clearly been an alarming uptick in atmospheric methane in recent years, following a flattening of concentrations from 2000 to around 2007. But the cause of this particular pattern has been hotly debated, with some blaming the fracked natural gas boom (natural gas is primarily composed of methane) and others pointing to causes such as agriculture.

    [Atmospheric levels of methane, a powerful greenhouse gas, are spiking, scientists report]

    Now, new research published Thursday in the journal Carbon Balance and Management …. point the finger at agriculture once again. And more specifically, at cattle and other livestock.

    “Just from livestock methane emissions, our revisions resulted in 11 percent more methane in a recent year than what we were previously estimating,” said Julie Wolf, lead author of the study who completed the work while a postdoc at the institute and now works at the Department of Agriculture. “It’s not the biggest contributor to the annual methane budget in the atmosphere, but it may be the biggest contributor to increases in the atmospheric budget over recent years…

    ….Cows and other ruminant animals release methane into the atmosphere as a result of a process called “enteric fermentation” — a technical term that basically refers to the digestive chemistry in the animals’ stomachs. As the Environmental Protection Agency explains, the methane produced in this process “is exhaled or belched by the animal and accounts for the majority of emissions from ruminants.”

    Furthermore, the animals’ waste also fills the atmosphere with methane depending on how it is handled, meaning that “manure management” is categorized as a separate source of methane emissions….

    Julie Wolf, Ghassem R. Asrar and Tristram O. West. Revised methane emissions factors and spatially distributed annual carbon fluxes for global livestock. Carbon Balance and Management. September 201712:16 https://doi.org/10.1186/s13021-017-0084-y

    • Our results suggest that livestock methane emissions, while not the dominant overall source of global methane emissions, may be a major contributor to the observed annual emissions increases over the 2000s to 2010s.