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Tag Archive: temperature

  1. Chillier Winters, Smaller Beaks

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    • researchers found no correlation with summer temperatures but a clear one for winter — the coldest winters were associated with the smallest beaks, whereas warmer winters were associated with larger beaks.

    Posted: 13 Jul 2017 05:20 AM PDT see full ScienceDaily article here

    …in the 1990s, researchers began to explore a new question concerning the relationship between climate and the evolution of beak size…..[before this study]… feeding habits were believed to be the greatest driving force in beak evolution…

    …[comparing] differences between individuals of the same species that are living in wildly different conditions…. the researchers found no correlation with summer temperatures but a clear one for winter — the coldest winters were associated with the smallest beaks, whereas warmer winters were associated with larger beaks.

    …Allen’s Rule, which states that warm-blooded animals living in cold climates will have shorter limbs and appendages than those that live in warmer climates. The biological mechanism behind this rule is thermoregulation — more body surface area helps animals to shed heat better whereas less surface area helps them to conserve it. Since a bird’s beak plays a large role in thermoregulation — it has lots of blood vessels and is not covered in feathers — researchers wondered whether hotter climates beget larger beaks and colder climates beget smaller ones. Indeed, studies revealed that climate has influenced beak size, but not which type of climate had more of an overall impact….

    Nicholas R. Friedman, Lenka Harmáčková, Evan P. Economo, Vladimír Remeš. Smaller beaks for colder winters: Thermoregulation drives beak size evolution in Australasian songbirds. Evolution, 2017; DOI: 10.1111/evo.13274

     

  2. Deadly heatwaves expected to continue to rise

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    • Half of the world’s population will be affected even with aggressive emissions reductions

    June 19, 2017  University of Hawaii at Manoa Science Daily full article

    Seventy-four percent of the world’s population will be exposed to deadly heatwaves by 2100 if carbon gas emissions continue to rise at current rates, according to a new study. Even if emissions are aggressively reduced, the percent of the world’s human population affected is expected to reach 48 percent.
    “We are running out of choices for the future,” said Camilo Mora, associate professor of Geography in the College of Social Sciences at the University of Hawaii at Manoa and lead author of the study. “For heatwaves, our options are now between bad or terrible. ….. The human body can only function within a narrow range of core body temperatures around 37oC. Heatwaves pose a considerable risk to human life because hot weather, aggravated with high humidity, can raise body temperature, leading to life threatening conditions.”
    …For example, by 2100 New York is projected to have around 50 days with temperatures and humidities exceeding the threshold in which people have previously died. That same year, the number of deadly days for Sydney will be 20, 30 for Los Angeles, and the entire summer for Orlando and Houston….
    Camilo Mora, Bénédicte Dousset, Iain R. Caldwell, Farrah E. Powell, Rollan C. Geronimo, Coral R. Bielecki, Chelsie W. W. Counsell, Bonnie S. Dietrich, Emily T. Johnston, Leo V. Louis, Matthew P. Lucas, Marie M. McKenzie, Alessandra G. Shea, Han Tseng, Thomas W. Giambelluca, Lisa R. Leon, Ed Hawkins, Clay Trauernicht. Global risk of deadly heat. Nature Climate Change, 2017; DOI: 10.1038/NCLIMATE3322
  3. Small climb in mean temperatures linked to far higher chance of deadly heat waves

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    An increase in mean temperature of 0.5 degrees Celsius over half a century… more than doubled the probability of a heat wave killing 100+ people in India, according to researchers

    June 7, 2017 University of California – Irvine See full story here

    …They found that when mean summer temperatures in the South Asia nation went from 27 to 27.5 degrees Celsius, the probability of a heat wave killing more than 100 people grew from 13 percent to 32 percent — an increase of 146 percent….

    Omid Mazdiyasni et al. Increasing probability of mortality during Indian heat waves. Science Advances, June 2017 DOI: 10.1126/sciadv.1700066

  4. Breeding pairs of plovers cooperate to resist climate change

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    June 5, 2017 FECYT – Spanish Foundation for Science and Technology with Point Blue contribution   See full ScienceDaily article here

    Most bird chicks need parental care to survive. In biparental species the chicks have greater chances of success if both parents participate in this task, especially under hostile situations. An international team of scientists has revealed that when temperatures rise, males and females in pairs of plovers shift incubation more frequently….The paper…analysed the behaviour of 36 populations of 12 plover species. Its results reveal that male plovers assist the females during daytime incubation. “Males’ participation in daytime incubation increases both with ambient temperature and with as the variability of maximum temperatures during the incubation period,” the expert stresses. The research demonstrates that a rise in temperature changes these bird pairs’ behaviour and their daily routine in terms of nest attendance….The conclusion of this new paper is that climate variations strongly influence parental cooperation.

    Orsolya Vincze, András Kosztolányi, Zoltán Barta, Clemens Küpper, Monif Alrashidi, Juan A. Amat, Araceli Argüelles Ticó, Fiona Burns, John Cavitt, Warren C. Conway, Medardo Cruz-López, Atahualpa Eduardo Desucre-Medrano, Natalie dos Remedios, Jordi Figuerola, Daniel Galindo-Espinosa, Gabriel E. García-Peña, Salvador Gómez Del Angel, Cheri Gratto-Trevor, Paul Jönsson, Penn Lloyd, Tomás Montalvo, Jorge Enrique Parra, Raya Pruner, Pinjia Que, Yang Liu, Sarah T. Saalfeld, Rainer Schulz, Lorenzo Serra, James J. H. St Clair, Lynne E. Stenzel, Michael A. Weston, Maï Yasué, Sama Zefania, Tamás Székely. Parental cooperation in a changing climate: fluctuating environments predict shifts in care division. Global Ecology and Biogeography, 2017; 26 (3): 347 DOI: 10.1111/geb.12540

  5. 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.

  6. Can Meadows Rescue the Planet from CO2?

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    An unusual research project is determining whether restoring California’s meadows can reduce atmospheric carbon dioxide

    By Jane Braxton Little on May 11, 2017 Scientific American

    …Scientists and land managers are heading into the mountains to measure the greenhouse gas activity at 16 hand-picked meadows—some recently restored, others degraded from a century of grazing and logging.

    The four-year study is part of California’s pioneering effort to reduce carbon emissions. The project is designed to determine whether restored meadows hold more carbon than those that have been degraded. The outcome could prove pivotal for California and the planet. Worldwide, soils store three times more carbon than vegetation and the atmosphere combined. If the research shows restored meadows improve carbon storage, it could stimulate meadow restoration around the world….

    A December study published in Nature… found rising temperatures are stimulating a net loss of soil carbon to the atmosphere. Warmer soils accelerate the flux, sending more carbon into the ground and more carbon dioxide back out into the atmosphere. As warmth increases microbial activity, decomposition and respiration outpace photosynthesis, particularly in the world’s colder places. …” The changes could drive a carbon–climate feedback loop that could accelerate climate change.”…

    …The research covers meadows from the base of Lassen Peak in the north to areas nearer to Los Angeles. The meadows range in elevation from 3,045 to nearly 8,700 feet; they include granitic, volcanic and metamorphic soils. A critical facet of the partnership is developing precise procedures for when and how to measure and analyze meadow greenhouse gases.

    ……a limited study conducted by the University of Nevada, Reno (U.N.R.). Scientists collected soil samples at seven meadows in the northern Sierra restored between 2001 and 2016, pairing restored sites with similar, adjacent unrestored sites….found an average of 20 percent more soil carbon in restored meadows, with one site recording an increase of over 80 percent. Meadows immediately begin storing carbon following restoration, with significant increases over 15 years, says Cody Reed, a research assistant working with Ben Sullivan, a U.N.R. soil scientist and assistant professor. The investigation seems to show restored meadows add soil carbon and also slow losses to the atmosphere.

    …[In another study] they found surprised them: Carbon dioxide emissions were unaffected by soil moisture content, and methane sequestration was prevalent, particularly on the dry side of wet meadow. The 2014 study also found plant species richness and soil carbon concentration appeared more important than soil moisture in explaining carbon fluxes.

     

  7. Warmer temperatures cause decline in runoff ratio and water supply

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    Finding could improve water supply forecasting

    May 11, 2017 National Center for Atmospheric Research/University Corporation for Atmospheric Research  (from ScienceDaily)

    …The study paints a detailed picture of how temperature has affected the runoff ratio — the amount of snow and rain that actually makes it into the river — over time, and the findings could help improve water supply forecasts for the Rio Grande, which is a source of water for an estimated 5 million people. The study results also suggest that runoff ratios in the Upper Rio Grande and other neighboring snow-fed watersheds, such as the Colorado River Basin, could decline further as the climate continues to warm.

    “The most important variable for predicting streamflow is how much it has rained or snowed,” said NCAR scientist Flavio Lehner, lead author of the study. “But when we looked back hundreds of years, we found that temperature has also had an important influence — which is not currently factored into water supply forecasts. We believe that incorporating temperature in future forecasts will increase their accuracy, not only in general but also in the face of climate change….

    Current operational streamflow forecasts depend on estimates of the amount of snow and rain that have fallen in the basin, and they assume that a particular amount of precipitation and snowpack will always yield a particular amount of streamflow.

    In recent years, those forecasts have tended to over-predict how much water will be available, leading to over-allocation of the river…”The effect of temperature on runoff ratio is relatively small compared to precipitation,” Lehner said. “But because its greatest impact is when conditions are dry, a warmer year can make an already bad situation much worse.”…

    Flavio Lehner, Eugene R. Wahl, Andrew W. Wood, Douglas B. Blatchford, Dagmar Llewellyn. Assessing recent declines in Upper Rio Grande River runoff efficiency from a paleoclimate perspective. Geophysical Research Letters, 2017; DOI: 10.1002/2017GL073253

  8. Global climate risk reduced significantly with aggressive emissions reductions

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    • takes less than 20 years for risk of extreme heat to halve from start of aggressive emissions reductions
    • climate payback with major GHG reductions comes faster than previously thought

    Posted: 03 Apr 2017 09:33 AM PDT  ScienceDaily article here

    Climate scientists have shown the early mitigation needed to limit eventual warming below potentially dangerous levels has a climate ‘payback’ much earlier than previously thought.

    Ciavarella and the team discovered that it takes less than 20 years in many regions for the risk of extreme seasonal temperatures (one-in-ten-year extreme heat events) to halve following the start of aggressive emissions reductions.

    Andrew Ciavarella added: “We show that the global exposure to climate risk is reduced markedly and rapidly with substantial reductions of greenhouse gas emissions. It had been thought previously that most of the benefits of mitigation would have been hidden by natural climate variability until later in the century.”…

    Andrew Ciavarella, Peter Stott, Jason Lowe. Early benefits of mitigation in risk of regional climate extremes. Nature Climate Change, 2017; DOI: 10.1038/nclimate3259

  9. Large Sections of Australia’s Great Reef Are Dead Due to Ocean Warming, Scientists Find

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    Washington Post March 19 2017  See full article here

    THE MEASURED warming of the planet is not hypothetical. Nor are its effects, which are happening now, not decades from now. An ecological catastrophe is unfolding off Australia’s coast: Humans are killing the Great Barrier Reef, one of the world’s greatest natural wonders, and there’s nothing Australians on their own can do about it. We are all responsible.

    An ocean water temperature spike last year caused a massive “bleaching” event, in which colorful corals turned an antiseptic, sickly white. Scientists believe that the reef will never be the same.

    The chances of the northern Great Barrier Reef returning to its pre-bleaching assemblage structure are slim given the scale of damage that occurred in 2016 and the likelihood of a fourth bleaching event occurring within the next decade or two as global temperatures continue to rise,” a major new study in the journal Nature reported last week….

    ….Alarmingly, but perhaps not surprisingly, the Australian government reports that sections of the reef are getting slammed again this year….

    There is little doubt that temperature is the culprit. Reefs far away from human runoff and other local risks are suffering. Corals in pristine water bleached just like those in dirty water. The Nature study quantified a relationship between exposure to warm water and the severity of observed bleaching.

    “Immediate global action to curb future warming is essential to secure a future for coral reefs,” the study warned. “Water quality and fishing pressure had minimal effect on the unprecedented bleaching in 2016, suggesting that local protection of reefs affords little or no resistance to extreme heat. Similarly, past exposure to bleaching in 1998 and 2002 did not lessen the severity of bleaching in 2016.”…

  10. Making cows more environmentally friendly

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    Posted: 29 Mar 2017 09:26 AM PDT ScienceDaily summary here

    An important discovery surrounding plants used to feed livestock has been released by scientists. They report that plants growing in warmer conditions are tougher and have lower nutritional value to grazing livestock, potentially inhibiting milk and meat yields and raising the amount of methane released by the animals. Higher amounts of methane are produced when plants are tougher to digest — an effect of a warmer environment. Methane is a potent greenhouse gas, around 25 times better at trapping heat than carbon dioxide. More than 95% of the methane produced by cows comes from their breath through eructation (belching) as they “chew the cud.”

    “Our research has shown that cultivating more nutritious plants may help us to combat the challenges of warmer temperatures. We are undertaking work at Kew to identify the native forage plants that are associated with high meat and milk production and less methane, attempting to increase their presence on the grazing landscape. We are also developing our models to identify regions where livestock are going to be exposed to reductions in forage quality with greater precision. It is going to be important to put plans in place to help those countries exposed to the most severe challenges from climate change to adapt to a changing world” said Dr Mark Lee.

    Mark A. Lee, Aaron P. Davis, Mizeck G. G. Chagunda, Pete Manning. Forage quality declines with rising temperatures, with implications for livestock production and methane emissions. Biogeosciences, 2017; 14 (6): 1403 DOI: 10.5194/bg-14-1403-2017