Ecology, Climate Change and Related News

Conservation Science for a Healthy Planet

Category Archive: Climate Change

  1. U.S. Coastal Cities Will Flood 40x More Often by 2050 and More Severely, Study Warns

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    • Major coastal flooding—expected to occur only once every 100 years—will inundate coastal cities an average of 40 times more often by 2050
    • Researchers took a detailed look at the risks as sea level rises. Their conclusion? Get ready now

    Cities lining the U.S. coasts should brace for a lot more flooding — from “nuisance” floods that shut down streets during high tides to deluges that take lives and wipe out infrastructure. In a new study published Wednesday, researchers from Princeton and Rutgers universities warn that the current flooding predictions, including those widely used by policy makers, don’t accurately reflect the frequency and types of floods that are likely to challenge American cities in the coming decades as global temperatures and sea levels rise.

    Their research found that major coastal flooding—expected to occur only once every 100 years—will inundate coastal cities an average of 40 times more often by 2050, likely overwhelming the cities’ abilities to protect themselves.

    After 2050, the picture looks worse. Major flooding could slosh through the streets of New York City every other month by the end of the century, while major floods could sweep into Seattle nearly every week

    Maya K Buchanan1,4, Michael Oppenheimer1,2 and Robert E Kopp3 Amplification of flood frequencies with local sea level rise and emerging flood regimes Published 7 June 2017 © 2017 IOP Publishing Ltd  Environmental Research Letters, Volume 12, Number 6

    Abstract The amplification of flood frequencies by sea level rise (SLR) is expected to become one of the most economically damaging impacts of climate change for many coastal locations. Understanding the magnitude and pattern by which the frequency of current flood levels increase is important for developing more resilient coastal settlements, particularly since flood risk management (e.g. infrastructure, insurance, communications) is often tied to estimates of flood return periods. The Intergovernmental Panel on Climate Change’s Fifth Assessment Report characterized the multiplication factor by which the frequency of flooding of a given height increases (referred to here as an amplification factor; AF). However, this characterization neither rigorously considered uncertainty in SLR nor distinguished between the amplification of different flooding levels (such as the 10% versus 0.2% annual chance floods); therefore, it may be seriously misleading. Because both historical flood frequency and projected SLR are uncertain, we combine joint probability distributions of the two to calculate AFs and their uncertainties over time. Under probabilistic relative sea level projections, while maintaining storm frequency fixed, we estimate a median 40-fold increase (ranging from 1- to 1314-fold) in the expected annual number of local 100-year floods for tide-gauge locations along the contiguous US coastline by 2050. While some places can expect disproportionate amplification of higher frequency events and thus primarily a greater number of historically precedented floods, others face amplification of lower frequency events and thus a particularly fast growing risk of historically unprecedented flooding. For example, with 50 cm of SLR, the 10%, 1%, and 0.2% annual chance floods are expected respectively to recur 108, 335, and 814 times as often in Seattle, but 148, 16, and 4 times as often in Charleston, SC.

  2. CO2 ‘tipping point’ triggered abrupt warming during glacial periods; gradual CO2 rise can lead to sudden change

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    Scientists throw light on mysterious ice age temperature jumps

    June 19, 2017 Cardiff University

    Scientists believe they have discovered the reason behind mysterious changes to the climate that saw temperatures fluctuate by up to 15°C within just a few decades during the ice age periods. In a new study published today, the researchers show that rising levels of CO2 could have reached a tipping point during these glacial periods, triggering a series of chain events that caused temperatures to rise abruptly.

    The findings, which have been published in the journal Nature Geoscience, add to mounting evidence suggesting that gradual changes such as a rising CO2 levels can lead to sudden surprises in our climate, which can be triggered when a certain threshold is crossed

    Previous studies have shown that an essential part of the natural variability of our climate during glacial times is the repeated occurrence of abrupt climate transitions, known as Dansgaard-Oeschger events….”These findings add to mounting evidence suggesting that there are sweet spots or ‘windows of opportunity’ within climate space where so-called boundary conditions, such as the level of atmospheric CO2 or the size of continental ice sheets, make abrupt change more likely to occur….

    Xu Zhang, Gregor Knorr, Gerrit Lohmann, Stephen Barker. Abrupt North Atlantic circulation changes in response to gradual CO2 forcing in a glacial climate state. Nature Geoscience, 2017; DOI: 10.1038/ngeo2974

  3. California, Southwest see record temperatures amid heat wave

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    June 21 2017

    Extreme Heat Seared the Southwest This Week; Daily record highs were set Wednesday in Needles, California (123 degrees), Las Vegas (114 degrees), Phoenix (117 degrees), Tucson, Arizona (115 degrees), Redding, California (110 degrees – tie), and Palm Springs, California (118 degrees – tie). The 115 degree high on Wednesday allowed Tucson to set a new record for longest streak of 115 degree temperatures, with three days….

    It’s so hot in Phoenix that airplanes can’t fly…..The National Weather Service broke out the magenta — a color category little known to the rest of the country — to illustrate parts of Arizona that would be under “rare, dangerous, and very possibly deadly” heat for the rest of the week.

    An all-time record in San Diego County: The temperature hit 124 degrees on Tuesday in Ocotillo Wells — the highest reading ever recorded in San Diego County, according to the National Weather Service.

    SF hits 88, breaking ’93 record, as heat wave hits Bay Area

    Heat records were broken all over the Bay Area today, according to the National Weather Service. Photo: National Weather Service

  4. Scientists stunned by Antarctic rainfall and a melt area bigger than Texas

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    • An area of West Antarctica more than twice the size of California partially melted in 2016 when warm winds forced by an especially strong El Nino blew over the continent.
    • Harbinger of future in Antarctica?

    Chris Mooney Washington Post  June 15 2017  see full article here

    ….In the Antarctic summer of 2016, the surface of the Ross Ice Shelf, the largest floating ice platform on Earth, developed a sheet of meltwater that lasted for as long as 15 days in some places. The total area affected by melt was 300,000 square miles, or larger than the state of Texas, the scientists report.

    That’s bad news because surface melting could work hand in hand with an already documented trend of ocean-driven melting to compromise West Antarctica, which contains over 10 feet of potential sea level rise.

    “It provides us with a possible glimpse of the future,” said David Bromwich, an Antarctic expert at Ohio State University and one of the study’s authors. The paper appeared in Nature Communications.

    “You probably have read these analyses of West Antarctica, many people think it’s slowly disintegrating right now, and it’s mostly thought to be from the warm water eating away at the bottom of critical ice shelves,” Bromwich continued. “Well, that’s today. In the future, we could see action at the surface of these ice shelves as well from surface melting. So that makes them potentially much more unstable.”…

    From ScienceDaily: Widespread snowmelt in West Antarctica during unusually warm summer Posted: 15 Jun 2017 05:46 AM PDT

    Julien P. Nicolas et al January 2016 extensive summer melt in West Antarctica favoured by strong El Niño Nature Communications 8, Article number: 15799 (2017) doi:10.1038/ncomms15799

    Abstract: Over the past two decades the primary driver of mass loss from the West Antarctic Ice Sheet (WAIS) has been warm ocean water underneath coastal ice shelves, not a warmer atmosphere. Yet, surface melt occurs sporadically over low-lying areas of the WAIS and is not fully understood. Here we report on an episode of extensive and prolonged surface melting observed in the Ross Sea sector of the WAIS in January 2016. A comprehensive cloud and radiation experiment at the WAIS ice divide, downwind of the melt region, provided detailed insight into the physical processes at play during the event. The unusual extent and duration of the melting are linked to strong and sustained advection of warm marine air toward the area, likely favoured by the concurrent strong El Niño event. The increase in the number of extreme El Niño events projected for the twenty-first century could expose the WAIS to more frequent major melt events.

  5. 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
  6. 2nd warmest May (by a fraction), 2nd warmest spring on record, despite no El Nino

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    May Continues a Ridiculous Warm Streak for the Planet

    By Brian Kahn  June 15th, 2017  Climate Central

    Another month is in the global temperature record books. While May just missed setting a record, the data is another reminder that climate change is making the world hotter and pushing it into a new state.

    This May was the second-warmest May on record, according to NASA data released on Thursday. The planet was 1.6°F (0.88°C) warmer than normal last month, trailing 2016 by just a 10th of a degree.

    …With May in the record books, NASA data also shows that this was the second-warmest spring on record, again trailing only 2016. NASA climate researcher Gavin Schmidt said the first five months of the year make it likely that this will be the second-hottest year on record trailing only, you guessed it, 2016.

    Last year’s record heat got a boost from El Niño. The absence of El Niño this year in some ways makes the planetary heat even more shocking, though it certainly fits a pattern.

    After all, May marked an all-time monthly peak for carbon dioxide levels in what’s become an annual rite of passage. Scientists found that carbon dioxide at Mauna Loa Observatory, the marquee measuring station, reached 409.65 parts per million (ppm) last month. That coupled with the second-hottest May on record are major markers of the current state of the world’s climate.

    This May was the second-hottest May on record. Credit: NASA GISS

  7. 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

  8. Marine reserves help mitigate against climate change, say scientists

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    June 5, 2017 University of York  full ScienceDaily article here

    Highly protected marine reserves can help mitigate against the impacts of climate change, a study by a team of international scientists has concluded….The study….evaluated existing peer reviewed studies on the impact of marine reserves around the world.Currently, only 3.5 per cent of the ocean has been set aside for protection with just 1.6 per cent fully protected from exploitation. International groups are working to raise the total to 10 per cent by 2020, while delegates to the International Union for the Conservation of Nature’s 2016 World Conservation Congress agreed that at least 30 per cent should be protected by 2030.

    Scientists say Marine Reserves and Marine Protected Areas (MPAs):

    • Protect coasts from sea-level rise, storms and other extreme weather events
    • Help offset climate-change induced declines in ocean and fisheries productivity
    • Provide refuges for species as they adjust their ranges to changing conditions
    • Can help combat acidification

    Callum M. Roberts, Bethan C. O’Leary, Douglas J. McCauley, Philippe Maurice Cury, Carlos M. Duarte, Jane Lubchenco, Daniel Pauly, Andrea Sáenz-Arroyo, Ussif Rashid Sumaila, Rod W. Wilson, Boris Worm, and Juan Carlos Castilla. Marine reserves can mitigate and promote adaptation to climate change. PNAS, June 2017 DOI: 10.1073/pnas.1701262114

  9. Global warming could push Earth’s rains northward, exacerbate stressed water supplies in West

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    • As the Northern Hemisphere warms faster than the Southern, Earth’s rain belts may shift to the North
    • Implications for areas where water supplies are already stressed including Western US

    By Andrea Thompson, Climate Central on May 31, 2017  read full article here

    The Earth’s rising temperature is expected to knock the global water cycle out of whack, but exactly how it will change is uncertain. Scientists, though, can look for clues as to what the future might bring in the major climate swings that have happened in the past.

    A new study that does just that suggests that Earth’s rain belts could be pushed northward as the Northern Hemisphere heats up faster than the Southern Hemisphere. That shift would happen in concert with the longstanding expectation for already wet areas to see more rain and for dry ones to become more arid.

    ….These changes in rain distribution could have implications for future water resources, particularly in areas where water supplies are already stressed, such as the western U.S. and parts of Africa…

  10. Larsen C Iceberg on Brink of Breaking Off

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    By Brian Kahn Published: May 31st, 2017  full ClimateCentral article here

    …the Larsen C crack is… in the final days of cutting off a piece of ice that will be one of the largest icebergs ever recorded….The crack has spread 17 miles over the past six days, marking the biggest leap since January.

    …The vast majority of ice shelves are losing volume due to rising ocean and air temperatures. That’s helped prime parts of West Antarctica for what might be unstoppable melt that could raise sea levels at least 10 feet. Researchers also recently found meltwater ponds are much more common than previously thought. They even discovered a roaring seasonal waterfall on the Nansen Ice Shelf.

    These and other findings make clear that the Larsen C crack is just one of many changes happening to Antarctica. Global warming has pushed temperatures up to 5°F higher in the region since the 1950s and they could increase up to 7°F further by the end of the century, putting more stress on ice…