Saturday, November 1, 2014

Climate Central - News

Climate Central is a nonprofit science and media organization created to provide clear and objective information about climate change and its potential solutions.
  1. Picture This: Amazing Antarctic & Halloween Treats

    The weather news this week was dominated by remembrances of Hurricane Sandy and the impact it is still having on rebuilding and resiliency efforts, as well as climate research. A brewing storm that could bring snow to parts of the East was also much Tweeted. But the most impressive pictures came from weather and climate-related events happening elsewhere around the globe, from a cyclone spinning over the Arabian Sea, to NASA research planes flying over the icy expanse of Antarctica to study seasonal ice melt. And then, of course, there were the signs of the season, from fall leaves and a frosty pumpkin, to some Halloween tricks and treats.

    Awe-inspiring Antarctica

    NASA kicked off the Antarctic leg of the 2014 Operation IceBridge campaign earlier this month, flying long missions over the southernmost continent in their DC-8 research plane.

    The IceBridge campaign’s aim is right in its name: It is bridging the gap between the termination of the ICESat satellite in 2009 and the expected 2016 launch of ICESat-2, its successor. IceBridge planes spend the Northern and Southern hemisphere summers collecting data from the Arctic and Antarctic, respectively, to maintain continuity between the two missions.

    The also take some truly spectacular photos.

    So far during the Antarctic campaign, their photographers aboard the plane have snapped images of the rugged Shackleton Range (named after an early 20th century Antarctic explorer, Ernest Shackleton):

    The mountains of Antarctica's Shackleton Range seen during IceBridge's survey of Recovery Glacier on Oct. 25, 2014.
    Click image to enlarge. Credit: NASA / Jim Yungel

    Along with the stark white expanse of the Antarctic Peninsula, one of the fastest warming places on the planet (air temperatures there have risen by about 5°F in the last 50 years):

    Antarctic Peninsula on the way back to Punta Arenas with @NASA_ICE

    — Ellen Stofan (@EllenStofan) October 29, 2014

    And then this stunning shot showing the shadow of the plane on sea ice rimming the continent, which reached a record high 20 million square kilometers (7.7 square miles) this winter. The rapid growth of Antarctic sea ice in recent years is more than offset by the precipitous decline of Arctic sea ice, and may be linked to global warming, which could be altering winds around the continent and melting more of the ice at the continent’s edge, providing a stable water layer for sea ice to form in:

    New video: #IceBridge on the trail of a sea ice mystery.

    — NASA ICE (@NASA_ICE) October 29, 2014

    Arabian Sea Storm

    Hurricane season may be winding down in the Atlantic Ocean basin, but elsewhere it’s still going strong. In the Arabian Sea this week, Cyclone Nilofar spun up to Category 4 status on Oct. 28, the strongest storm in the sea since Phet in 2010.

    NASA’s Terra satellite took an image of the storm that day, with it’s 14-mile-wide eye clearly visible:

    NASA's Terra satellite captured Tropical Cyclone Nilofar moving north in the Arabian Sea on Oct. 28, 2014.
    Credit: NASA Goddard MODIS Rapid Response Team

    Before reaching northwest India, the cyclone was torn apart by wind shear, helping those areas dodge the worst effects, though heavy downpours and flooding were still a threat.

    Happy Halloween!

    We couldn’t resist showing some of our favorite weather-related Halloween pics that popped up on Twitter today.

    First up, a Jack-o-lantern that got some impromptu decoration thanks to an overnight snowfall in Wisconsin:

    MT @JeffLast RT @WeatherHolley: #Snow on the pumpkin in Wausau, WI.

    — Jonathan Erdman (@wxjerdman) October 31, 2014

    Find out here if your city has had snow on Halloween before.

    One weatherman had fun with his green screen, giving folks a spine-tingling forecast:

    Let the kids watch @WDRBNews this morning. Bones Redfield will be showing up soon! They will love it!

    — Jude Redfield (@JudeRedfield) October 31, 2014

    And one tyke should surely win any costume contest he enters, dressing up as the man synonymous with hurricane coverage, Jim Cantore:

    The mouth wide open is a slam dunk smile MT @ShawnRTV6: Best. Costume. Ever. Mini @JimCantore @weatherchannel

    — Jim Cantore (@JimCantore) October 31, 2014

    Give that kid extra candy! And have a Happy Halloween! 

  2. Sandy Motivates NY to Explore Microgrids

    In many ways, the Rockaways is the end of the line.

    In essence, it’s the edge of America — a spindly peninsula acting as a barrier island exposed to the ravages of the Atlantic on the eastern edge of New York City. An hour from Manhattan on the subway, it’s the terminus of the A Train, the only rapid transit access to the rest of the city for the 100,000 people who live there.

    New York City's recovery effort at the Rockaways following Hurricane Sandy in 2012.
    Credit: New York City Dept. of Transportation/flickr

    The Rockaways is also where Long Island’s power lines end.

    That’s one of the reasons New York City officials singled out the Rockaways as the ideal place for a microgrid experiment after the spit of land was thrashed by Hurricane Sandy two years ago. The megastorm killed at least 9, stranded more than 34,000 without power, and submerged homes in seawater as the Atlantic surged around them.

    It underscored New York’s vulnerability to nature’s wrath as a low-lying coastal city and it is at the root of why the city government issued a climate change response plan called “A Stronger, More Resilient New York.”

    Deep within that report, the city suggested that the Rockaways were an excellent candidate for a microgrid for several reasons. The peninsula is vulnerable to hurricanes and storm surge. Extreme weather is almost guaranteed to keep the Rockaways in the dark for days or weeks. And, being at the tail end of Long Island Power Authority’s grid means it could be easily separated from the grid and operate autonomously under its own power.

    A microgrid — which can take many forms, but is basically a self-contained power grid with its own electric and/or battery-powered generators — would link together critical services such as hospitals, schools, grocery stores and gas stations, etc.

    When the main grid goes down in a storm, the generators can power emergency rooms, classrooms and supermarkets, mitigating a storm’s devastation and keeping emergency services available.

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    While New York City called for a study to contemplate a microgrid in the Rockaways, the state is moving more aggressively on microgrids there and elsewhere throughout the state.

    Management of the Rockaways’ power grid has been taken over by PSEG Long Island, part of Public Service Enterprise Group, which in early October issued an updated plan called Utility 2.0 that aims to modernize the company’s electric system and may open the door to a microgrid project, said Jackson Morris, formerly of Pace University’s Energy and Climate Center and now director of eastern energy for the Natural Resources Defense Council.

    Utility 2.0 proposes a $76 million investment in unspecified ways to help reduce and more effectively manage energy use at the Rockaways so the company can wait to upgrade transmission lines connecting the peninsula within New York City to Long Island.

    “It’s basically infrastructure deferment, but there’s a good chance a lot of the proposals that would come forward would have microgrids,” Morris said.

    Microgrids are the focus of a new New York State program called NY Prize, a $40 million competition announced in August challenging communities and entrepreneurs around the state to design community microgrid projects.

    Sunset over a Sandy-ravaged Rockaways in New York City in December 2012.
    Credit: Cgc76/flickr

    NY Prize, administered by NYSERDA, the New York State Energy Research and Development Authority, challenges communities throughout the state to make themselves more able to withstand extreme weather.

    Mark Torpey, NYSERDA director of research and development, said he hopes 30 to 40 proposals would be entered in the contest, and 10 or so would be given money to develop their proposals. The best would get funding for implementation.

    “Microgrids for critical facility resiliency — many folks here think that this type of microgrid could be very helpful if it’s done right,” Torpey said. “If you have shop and school assets serving a public good, and you’ve got the ability to keep the lights on when the grid is down, you’ve got the ability to provide critical services.”

    Further details about the NY Prize competition and how to submit proposals will be announced later this fall.

    New York State is also trying to work out some regulatory challenges that might face microgrid projects through a plan called “Reforming the Energy Vision,” announced in 2013.

    Morris said Reforming the Energy Vision, or REV, proposes to find ways to transform the way electric power is distributed in New York so renewables, microgrids and other innovations can be more effectively integrated into the system. It also aims to make power distribution facilities more nimble in response to outages in extreme weather.

    The proposal would help smooth the way for new projects such as Con Edison’s Brownsville demand management project in Brooklyn, which aims to use microgrids and battery storage to more effectively manage the use of electricity there, helping to save energy in a fast-growing area.

    If New York state regulators approve the REV plan, it will take years to transform the state’s power distribution system. Even so, the plan is a start toward preventing tens of thousands or maybe millions of New Yorkers from being stranded without power for weeks, even if those efforts aren’t ready before the next hurricane takes aim at New York City.

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  3. Ozone Hole Recovery Continues, Albeit a Little Slower

    The ozone hole is a gash in the stratosphere, like a festering wound high above the earth’s surface. Scientists first diagnosed the problem in the mid-1980s and recommended a course of action to treat the problem. And today, NASA announced that recovery has continued, though slightly slower this year compared to years past.

    An animation showing the ozone hole in October, the month usually following the ozone hole minimum, from 1979-2014.

    “This is a good story for ozone. If you look back to 1998-2006 period, the last couple years are better than what we saw back then. We see that in size, the aerial coverage of the ozone hole and depth of ozone hole,” said Paul Newman, chief scientist for atmospheres at NASA's Goddard Space Flight Center.

    This year’s ozone hole maximum topped out at 9.3 million square miles, or roughly the size of North America. That might sound bad, but it’s 2.2 million square miles smaller than the single-day record set in 2000. This year’s maximum is about on par with last year’s maximum, something Newman said is more likely due to year-to-year variability than a turn for the worse.

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    The ozone layer’s thickness also continues to grow since bottoming out in 1994.

    At its minimum thickness this year, ozone was 114 Dobson units, up from a single-day minimum of 73 Dobson units in 1994.

    Not familiar with Dobson units? How odd. In plain English, that means if you took the ozone layer from the stratosphere and brought it to the ground, this year’s minimum would measure a little more than a twenty-fifth of an inch thick or roughly the thickness of that credit card in your wallet.

    Ozone concentrations on September 11, 2014, the day the ozone hole reached its peak size this year.
    Click image to enlarge. Credit: NASA Goddard Space Flight Center

    That impossibly thin layer performs an immensely important function of keeping harmful ultraviolet radiation at bay. Though the ozone hole is an issue over Antarctica, it’s impacts can spill into other parts of the stratosphere, the second layer of the earth’s atmosphere.

    “When the ozone hole breaks up, it get smeared and mixed into other parts of the stratosphere. Think of it as a bucket of white paint. If you put a red dollop in the middle and stir it and everything turns pink,” Newman said.

    That can increase the chances of harmful ultraviolet radiation reaching the ground over other parts of the globe, particularly the Southern Hemisphere.

    Shifts in the size and thickness of the ozone hole also have an impact on the climate (though it bears repeating, the ozone hole is not equivalent with climate change). Some research has tied the ozone hole with shifts in Antarctic wind patterns and subsequent growth of sea ice in the region, though Newman said what's happening with Antarctic ice is still being actively researched. Those wind shifts have also likely masked some of the warming effects greenhouse gases have had on the rest of the planet. As the ozone hole continues to heal, temperatures could rise in the region, posing a bit of a double-edged sword.

    The ozone hole was first reported by scientists in 1985 with the main cause linked to certain ozone-destroying chemicals, mostly used as refrigerants. In 1987, countries around the world created the Montreal Protocol, a plan to phase out those chemicals and restore the ozone to a clean bill of health. The plan appears to be working, though Newman said that more research is needed to determine the exact factors at play.

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  4. Extreme Halloween: Ghoulish Weather Records

    By Climate Central

    Hopefully your pumpkin is carved, the candy bowl is full and you haven't overdosed on candy corn yet because Friday is Halloween. This year's holiday has already set one record for the number of costumes that Americans purchased, including a whopping $350 million on pet costumes. But we happen to be interested in some other records, specifically the trick or treat of weather extremes.

    Find your city in the drop-down menu below to see just how hot or cold it has gotten on the most ghoulish day of the year. And if you're in a cold weather locale, be sure to see how much snow has graced the ground on All Hallows' Eves past.

    This year, some locations could be in store for some weather tricks. The National Weather Service has issued freeze warnings in the central Midwest and winter storm warnings in California's Sierra Nevada (though many there might consider precipitation there a treat).

    While the impacts of climate change are difficult to detect against the variability of a single day’s climate, regionally averaged observations show that falls are getting warmer in the U.S. and the first frost of the season is coming later. The amount of warming differs by region, but across the entire country this time of year is getting warmer. 

    Check out the Halloween climate extremes in your city:  

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  5. Snow! Or Not. Why Snow Is Hard to Forecast

    Maybe you saw the maps making the rounds on Twitter and elsewhere on the web: “Snow!” some shouted. Inches of it blanketing the Northeast this weekend, thanks to a brewing storm.

    Maybe you also saw the responses from seasoned meteorologists warning those projections should be taken with a healthy grain of rock salt.

    Possible precipitation (including chances of snow in some areas) due to a storm brewing off the East Coast this weekend.
    Click image to enlarge. Credit: NOAA/NWS

    The reason, of course, is that the forecasting of when, where and how much snow falls is difficult to accurately pin down, particularly several days in advance. But why is that?

    Some of the difficulty comes from the inherent uncertainty involved with any forecast more than about 4-5 days out, meteorologists say. On top of that, precipitation is trickier to forecast than temperature trends, with snow being a particularly finicky precipitation that requires the right combination of factors.

    “Everybody likes to dream of a big storm,” said Steve DiRienzo, a meteorologist with the National Weather Service Office in Albany, N.Y., who said with a hint of exasperation that they had been fielding calls about the potential snow since last weekend.

    Imperfect models

    In general, it’s hard to make specific forecasts for things like snow events, especially the further away from the event you get. “There’s more that can go wrong” within the models that guide those forecasts, said Bob Oraveck, a lead forecaster with NWS’s Weather Prediction Center in College Park, Md.

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    A lot of what can happen with a given day’s weather, especially when something like a snowstorm is involved, depends on the little details that can have big effects over time. If the model has one of those little details wrong at the beginning, its projection of what will happen several days out can become more and more off base.

    “The skill in the details gets worse and worse with time,” Oraveck told Climate Central.

    Some of this has do to inherent limitations. Models are run using current atmospheric conditions, gathered by sampling efforts like weather balloons launched from NWS offices to see what’s happening in the atmosphere at a certain time. But those sampling efforts don’t cover the whole planet, and the Earth’s atmosphere is a large, interacting system — what’s happening on the West Coast today will affect the East Coast a few days later, for example.

    “If we could sample the entire globe perfectly, we’d have a perfect forecast,” Oraveck said. But meteorologists can’t do that, so they’re left with the imperfect simulations they can get.

    Those issues aren’t unique to snowstorms though, as a forecast for summer rains can easily go bust. There’s just something about snow that makes people sit up and pay attention in a way they might not during balmier times of the year.

    “It becomes more visual when it’s snow,” Oraveck said. “You don’t really notice it as much when it’s rain.”

    Rain vs. Snow

    Rain on its own can even be a pain to forecast compared to high and low temperatures, in part because of  “the scale of the phenomena that you’re forecasting,” Oraveck said. You may know it’s supposed to be colder than average over the entire eastern half of the country and that there’s some potential for snow over some part of it, but “the actual size of the precipitation area is going to be smaller than the” below-temperature area, he said, and smaller areas are always harder to resolve in models and forecast for.

    Also, “it takes the right combination of atmospheric events” just to get precipitation to fall, “but then it has to be cold enough for snow,” DiRienzo said.

    In the dead of winter, that’s not an issue. But late October-early November “is a transition time,” DiRienzo said. “So you’re always unsure about how cold it’s going to be.”

    Main impacts from weekend storm will be strong winds/minor coastal flooding. Accum. snow unlikely. Please retweet.

    — NWS Boston (@NWSBoston) October 30, 2014

    And it doesn’t just need to be cold at the ground: the whole temperature profile of the atmosphere is key. “It’s critical because if you have any warm layers in there you can end up with more mixing and even rain,” said Eric Schwibs, a meteorologist at the NWS office in Portland, Maine.

    The ocean is also warmer this time of year, mitigating temperatures, especially near the coast, and the ground isn’t frozen yet, making it harder for any snow that does fall to stick.

    At a transition time of year like this, where snow falls and sticks is often dependent on elevation, with snows more likely to fall on mountains than on the valleys between them. Lakes can also ramp up snowfall — the infamous eponymous lake effect — by providing more moisture. So snowfall amounts can be highly localized.

    A slight change in temperature or location then can mean the difference between several inches of snow, a mix of snow and rain, or just a cold, soggy day.

    This storm

    So all that said, you probably still want to know what’s going to happen this weekend, huh?

    This won’t be a surprise if you’ve paid attention, but that’s still somewhat up in the air. Each run of the weather models has been pushing the low-pressure center at the heart of the storm further out to sea, making snow less and less likely for much of the Northeast.

    Schwibs said that southern Maine, particularly higher elevations, could see some snow in the air, but it’s uncertain whether or not it will stick. Currently most snow showing up in the models is only in northern Maine, though flurries elsewhere aren’t out of the question (and recent runs have put some snow in higher elevations of the Southeast).

    Meanwhile, up to a foot of snow coming to the mountains of NC. Get ready for #snOMG video.

    — Eric Fisher (@ericfisher) October 30, 2014

    But if model runs today and tomorrow shift the storm back to the coast, then the picture could change. Essentially, the storm’s track is “critical,” Schwibs said.

    Of course, snow isn’t the only hazard the storm could produce. It is expected to affect weather from Atlanta to Maine, and will bring high winds to some areas and much colder temperatures than have been in place in recent days. It could also bring coastal flooding and high waves at sea, DiRienzo said.

    “It’s a very big, powerful storm. I think it bears watching,” he said. “So we’ll have to just see what happens.”

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  6. An Ill Wind Blows in Antarctica, Threatens Global Flooding

    Foreboding winds of change are blowing over the already gale-swept South Pole, threatening to hasten Antarctic melting and worsen flooding around the globe.

    The Southern Ocean’s legendary winds have been blowing more fiercely and in a more poleward direction since the 1950s. Temperature observations are sparse around the hostile continent, but scientists recently modeled the ocean current knock-on effects of these wind changes, which have been caused by ozone thinning and by the buildup of greenhouse gases.

    The scientists were blown away by the vicious climate change feedback that they unearthed.

    Antarctic tempest.
    Credit: Eli Duke/flickr

    The researchers reported that the shifting winds “produce an intense warming” just below the surface of the ocean. The wind changes were found to be heaving warm currents from deeper waters up into a zone where the Antarctic ice sheet is vulnerable to melt and crumble from beneath — the area where towers of ice sit atop submerged ground.

    “It’s a very simple mechanism that we’re identifying,” said Stephen Griffies, a National Oceanic and Atmospheric Administration scientist who contributed to the modeling research, which was published in Geophysical Research Letters. “You raise the warm water to the depth of the ice shelves through the wind changes.”

    The 8 inches of sea level rise produced by global warming so far has worsened the tolls of storm surges, including those caused by Hurricane Sandy, and subjected coastal cities to high tide flooding of unprecedented frequency. But the effects of those 8 inches pale when compared with the several feet of additional flooding expected as the century progresses.

    The world’s biggest reserves of above-water ice are in Antarctica, and understanding the rate at which the ice sheet will slough into the sea could help researchers refine sea level rise forecasts. Current projections would see 2.6 percent of the world’s population living in areas that regularly flood by century’s end. If Antarctica proves less stable than hoped, the catastrophe could be even worse than currently anticipated.

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    The effects of wind changes, which were found to potentially increase temperatures in the Southern Ocean between 660 feet and 2,300 feet below the surface by 2°C, or nearly 3.6°F, are over and above the ocean warming that’s being caused by the heat-trapping effects of greenhouse gases. “We’re not even adding heat to the ocean,” Griffies said of the modeling effort.

    The discovery accompanies more bad news for the future of Antarctica’s ice, which was published a month ago in Nature Communications. A cold layer of freshwater that’s sitting at the ocean surface around Antarctica, caused by melting ice and contributing to the expansion of sea ice, was found through climate modeling to be preventing warm water from reaching the surface, where it would normally cool. Instead, that warm water, which is shuttled south by underwater currents from the tropics, is being thrust against Antarctica’s ice sheet and its ice shelves, exacerbating melting and hastening sea level rise.

    “The pattern and magnitude of warming shown in this [Geophysical Research Letters] study is alarming,” said Nick Golledge, a Victoria University of Wellington researcher who led the Nature Communications study. “Since they use a very high-resolution model, they are able to capture behavior that most models cannot simulate, so it's a great piece of work.”

    Richard Alley, a Penn State geosciences professor who wasn’t involved with the new study, said far more work is needed to understand the effects of wind and ocean changes in the Southern Hemisphere’s most frigid stretches. “A huge difficulty in all of this is that the Southern Ocean is big, deep, complex, hard to study, and in general less known than most of the world ocean,” he said. But he said the new research provides a “useful contribution” to improving our understanding of the Southern Ocean, its winds and its currents.

    “The main result supports and extends earlier work, showing that human forcing contributes to changing winds that contribute to subsurface ocean warming, affecting some grounding zones of the ice sheet,” Alley said.

    Those cascading effects might be difficult to comprehend, let alone see, for coastal communities hundreds or thosuands of miles away from the inhospitable continent. But they threaten to worsen the sinking feelings felt by those communities for years to come.

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  7. Two Years On: Sandy Inspires Storm of Climate Research

    By Andrea Thompson and Brian Kahn

    The two years that have passed since Hurricane Sandy crashed into the New Jersey shoreline have not been enough time for scientists and researchers to make much headway on the hows and whys of the Northeast’s epic storm. But that’s not because they aren’t trying.

    Damage on Staten Island in the immediate aftermath of Sandy. 
    Credit: Somayya Ali/NASA GISS

    In fact, Sandy has spurred an unprecedented amount of research, attempting to tackle the questions about what role climate change might have played in producing or worsening the storm, how global warming might influence similar storms in the future, and why the storm caused so much damage — $19 billion in the New York City area alone.

    “It’ll be one of the most studied storms,” said Gary Lackmann, an atmospheric scientist at North Carolina State University who has looked into the role warming might have played in guiding Sandy’s track and intensity.

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    Here, Climate Central takes a look at some of those research avenues exploring the role climate change played in Sandy and how the so-called superstorm impacted our evaluation of current and future coastal risks.

    Of Sea Level Rise and Storm Surge

    The clearest connection between climate change and Sandy’s impacts is sea level rise. Warming oceans and melting land ice have contributed in large part to the nearly 12 inches of sea level rise in the New York area over the past 100 years, a rate faster than the global average of about 8 inches.

    Sea level rise is contributing to coastal erosion in some places such as the Jersey Shore, but Philip Orton, an oceanographer at the Stevens Institute for Technology in Hoboken, N.J., said that how it interacted with storm surge — the wall of water that hurricanes and other storms push ashore — is what helped drive much of Sandy’s damage. And the future 1-2 punch of storm surge and sea level rise could further reshape the physical and social landscape around New York and New Jersey.

    “Sea level rise is very uncertain so that’s part of the problem for long-term planning,” Orton said.

    Of course there’s no uncertainty whether it’s going to happen, it’s just a question of how high seas will go. The New York City Panel on Climate Change report released last year shows that by the 2050s, mid-range sea level rise estimates could be from 11-24 inches in the region.

    A view of downtown Manhattan.
    Credit: Brian Kahn

    “The answer is definitely, ‘Yes,’” when it comes to questions of whether future sea level rise would increase the risk of Sandy-like flooding, said Adam Sobel, a hurricane modeler at Columbia University’s Lamont-Doherty Earth Observatory. That raises the question of how to adapt to those increasing risks, whether it be building sea walls or reinforcing natural defenses or planning a retreat from the sea.

    “We know we have at least the height of 100-year storm we weren’t ready for,” Orton said. “So it’s getting to the point, there’s a certain height of sea wall we need that’s a little higher than we currently have and the tough question is how high do you actually go.”

    Beyond the height of sea walls is also the question of what the future has in store for the city’s outer neighborhoods. Raising neighborhoods and adding dunes and berms offer protection in the present but rising seas could eventually claw away at those gains.

    “We know that there’s already many feet of sea level rise baked in because of the heat and carbon dioxide in atmosphere. It’s going to be there, it’s not going to disappear,” Orton said.

    Role of Warming

    The role of warming in other aspects of Sandy’s landfall and lifecycle, including the unusual track it took and the strength it achieved are much harder to pin down.

    Inspired by that unprecedented path, Lackmann looked at how warming might have influenced it and Sandy’s intensity. Using computer simulations to mimic warming and greenhouse gas levels before 1900 and after 2100, he found that the amount of warming to date only slightly strengthened Sandy and caused it to have a more northerly landfall.

    “The past to current just didn’t change things as much as maybe would be expected,” he told Climate Central.

    But the future Sandy was considerably stronger and made landfall even further north, along Long Island.

    The study was what Lackmann called “a thermodynamic experiment,” looking to see what role warming temperatures and the associated increase of water vapor in the atmosphere may have played by a process known as condensational heating (or the heat released when water vapor condenses in the atmosphere). The experiments kept the atmospheric situation that guided Sandy (with a low-pressure area over the U.S. and a high pressure dome over Greenland). The results of the study were detailed online recently in the Bulletin of the American Meteorological Society.

    In principle, a more holistic look at the role warming played in Sandy could be done in a similar way — as it has been for other extreme events — running computer model simulations with and without the warming induced by greenhouse gases, but because Sandy was such a rare event, the amount of computer time and expense involved are prohibitive for the time being, Sobel said.

    “I think that if someone really wanted to do it now, with a storm like Sandy, which the models can resolve pretty well,” they could, he told Climate Central, but for the places that possess such models, it would mean dropping all other work. And being able to find the signal of warming in such an effort would depend on how strong the warming effect was — a large, robust effect would show up with fewer model runs, but a small effect would take much longer to parse out.

    Overall, though, the lack of studies showing a clear role from warming in Sandy “doesn’t mean that there is no climate change role, it just means that the science isn’t there,” Sobel said.

    Hybrid Storm

    Adding to the difficulty of evaluating the role of warming in a storm like Sandy was the transition it made from a tropical to an extratropical cyclone, and the way it merged with low-pressure systems to become a “hybrid” storm.

    There is much more research suggesting that tropical cyclones will become more intense, but the research into extratropical cyclones hasn’t really been looked at from this angle, Sobel said.

    “We do not have anywhere near the number of historical records of such events as we do pure tropical hurricanes, and our understanding of hybrids is also not at the same level as our understanding of hurricanes,” said MIT’s Kerry Emanuel, one of the main scientists who has researched the link between tropical cyclones and climate change.

    “Sandy has catalyzed new research on hybrids, but our current climate models are probably not up to the task of simulating them, so we cannot use them with confidence to project how they might change with changing climate,” Emanuel told Climate Central in an email. “But I would bet that we will know much more about hybrids in another 10 years or so.”

    The tracks that hurricane Sandy might have taken in the past under less warming (green), today under current warming (blue) and with future warming (red), compared to the National Hurricane Center's estimation of Sandy's actual track.
    Credit: Lackmann/BAMS

    Strange Track and Arctic Influence

    The strange track taken by Sandy, moving northward along the east coast of the U.S. before making a sharp turn westward and slamming into New Jersey, was one of the aspects of the storm that generated particular research interest.

    Sobel, along with colleague Timothy Hall of NASA’s Goddard Institute for Space Studies, used computer models to simulate millions of “synthetic” hurricanes, and worked out that Sandy’s track was a 1-in-700-year event.

    The unusual track also piqued the interest of another scientist, Jennifer Francis of Rutgers University. “There were so many interesting things about Sandy that got my antennae quivering,” she said in an email.

    What caused Sandy to take its left-hand turn into the U.S. was what is known as a blocking pattern, where kinks in the jet stream — which normally guides storms from west to east — get stuck. In this case, a high-pressure ridge in the jet became stuck over Greenland, which forced Sandy to the west.

    Francis had just published work suggesting that the amplified warming of the Arctic and associated sea ice melt there was forcing the jet stream into the wavier, blocking patterns. As the Arctic warms, she and her colleagues argue, the temperature difference between the Arctic and the tropics is reduced, and because that temperature difference is what fuels the jet stream, the Arctic warming leads the jet stream to slow and get stuck.

    “We were just coming off of a record-smashing low sea-ice year in 2012,” Francis said. “The block that played such a key role in Sandy's ‘weirdness’ seemed like an amazing coincidence.” And an amazing research opportunity that Francis and some colleagues immediately began to explore.

    Other researchers aren’t yet sold on this link between Arctic amplification and blocking events, as climate models don’t seem to clearly produce it. But whether the models are wrong or if the link doesn’t pan out is something more research will surely look into.

    Risky Business But Also Opportunities

    Parsing the underlying climate factors that drove Sandy to its fateful encounter with the Northeast is important, but ultimately how that knowledge is used to prepare for the next storm is what really matters.

    “Maybe 10 years ago I would’ve asked how do I layer my power infrastructure data over my transportation data over my population and then put a hurricane on top,” said David Titley, a retired Navy Rear Admiral. “Now what people are looking for is the nonlinear relationships between those dynamic systems so when I put a hurricane on top of this, I can better understand the cascading failures.”

    Sandy damage in the Rockaways neighborhood of Brooklyn.

    Titley now runs the Center for Solutions to Weather and Climate Risk at Penn State, a relatively new research endeavor, which is focused on solutions and opportunities offered by weather and climate predictions and data to planners across a variety of sectors.

    Sandy’s rampage coincided with what many see as the rise of big data, with streams of information being returned from weather buoys, cell phones, security cameras, population surveys and other sensors that permeate our daily lives. That wealth of data is available to scientists and decision makers to pinpoint where failures in responding to the storm broke down and consequently need to be shored up.

    Some of the findings reinforce longstanding knowledge, such as the fact that poor and underserved communities were disproportionately affected by the storm. But data on those and other impacts coupled with climate projections can help pinpoint how to best spend some of the billions of money available for rebuilding and strengthening the city’s response to future storms.

    “If I had $50 million and I know what that buys me, then I need to understand what the best use is,” Titley said.

    The other big challenge is bringing this approach to the Akron, Ohios and Laredo, Texases of the world — smaller cities that might not have as many resources or sophisticated disaster response systems as New York. Titley said the ultimate goal is to provide targeted and contextual climate information to city planners, but in the short term, he said the goal is to “give people the basic knowledge so they can at least know what to ask for and know how to ask it.”

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  8. Hydropower May Be Huge Source of Methane Emissions

    Imagine nearly 6,000 dairy cows doing what cows do, belching and being flatulent for a full year. That’s how much methane was emitted from one Ohio reservoir in 2012.

    Reservoirs and hydropower are often thought of as climate friendly because they don’t burn fossil fuels to produce electricity. But what if reservoirs that store water and produce electricity were among some of the world’s largest contributors of greenhouse gas emissions?

    Harsha Lake, a large reservoir near Cincinnati, Ohio, emitted as much methane in 2012 as roughly 5,800 dairy cows would have emitted over an entire year. Credit: Firesign/flickr

    Scientists are searching for answers to that question, as they study how much methane is emitted into the atmosphere from man-made reservoirs built for hydropower and other purposes. Until recently, it was believed that about 20 percent of all man-made methane emissions come from the surface of reservoirs.

    New research suggests that figure may be much higher than 20 percent, but it’s unclear how much higher because too little data is available to estimate. Methane is about 35 times as potent a greenhouse gas as carbon dioxide over the span of a century.

    Think about man-made lakes in terms of cows passing gas: Harsha Lake, a large reservoir near Cincinnati, Ohio, emitted as much methane in 2012 as roughly 5,800 dairy cows would have emitted over an entire year, University of Cincinnati biogeochemist Amy Townsend-Small told Climate Central.

    Methane emissions from livestock are the second-largest source of methane emissions in the U.S., behind crude oil and natural gas, according to the U.S. Environmental Protection Agency. But the EPA’s greenhouse gas emissions estimates do not yet account for methane emissions coming from man-made reservoirs.

    Part of the reason is that, generally, very little is known about reservoirs and their emissions, especially in temperate regions, such as in the U.S., where few studies have been conducted.

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    In 2012 study, researchers in Singapore found that greenhouse gas emissions from hydropower reservoirs globally are likely greater than previously estimated, warning that “rapid hydropower development and increasing carbon emissions from hydroelectric reservoirs to the atmosphere should not be downplayed.”

    Those researchers suggest all large reservoirs globally could emit up to 104 teragrams of methane annually. By comparison, NASA estimates that global methane emissions associated with burning fossil fuels totals between 80 and 120 teragrams annually.

    But how much reservoirs contribute to global greenhouse gas emissions is “still a big question mark,” because the issue remains relatively unstudied and emission rates are highly uncertain, said John Harrison, an associate professor in the School of the Environment at the Washington State University-Vancouver whose research focuses on how reservoirs can be managed to reduce greenhouse gas emissions.

    “So I don’t think we really know what the relative greenhouse gas effect of reservoirs is compared to other sources of energy in the U.S.,” he said.

    Research at Harsha Lake may help scientists better understand how reservoirs contribute to climate change.

    In a study published in August, Townsend-Small and researchers from the EPA found that Harsha Lake emitted more methane into the atmosphere in 2012 than had ever been recorded at any other reservoir in the U.S.

    “When you compare the annual scale of the methane emission rate of this reservoir (Harsha Lake) to other studies, it’s really much higher than people would predict,” EPA research associate and Harsha Lake study lead author Jake Beaulieu told Climate Central.

    Scientists have long thought reservoirs in warmer climates in the tropics emitted more methane than reservoirs in cooler climates, but the research at Harsha Lake shows that may not be the case, Townsend-Small said.

    “We think this is because our reservoir is located in an agricultural area,” she said.

    Methane is generated in reservoirs from bacteria living in oxygen-starved environments.

    “These microbes eat organic carbon from plants for energy, just like people and other animals, but instead of breathing out carbon dioxide, they breathe out methane,” Townsend-Small said. “These same types of microbes live in the stomachs of cows and in landfills, which are other sources of methane to the atmosphere.”

    Runoff from farmland around Harsha Lake provides more nutrients in the water, allowing algae to grow, just like numerous other reservoirs surrounded by agricultural land across the country.

    Lake Travis near Austin, Texas.
    Credit: Bobby Magill

    Methane-generating microbes feed on decaying algae, which means that lakes catching a lot of nutrient-rich agricultural runoff generate a lot of methane.

    “There are a very large number of these reservoirs in highly agricultural areas around the U.S.,” Townsend-Small said. “It could be that these agricultural reservoirs are a larger source of atmospheric methane than we had thought in the past.”

    Emissions from reservoirs in all climates could be underestimated because of a discovery Beaulieu’s team found at Harsha Lake: The area where a river enters a man-made lake emits more methane than the rest of the lake overall.

    Nobody has measured that before, Beaulieu said.

    Most other research studying reservoir methane emissions doesn’t account for how emissions may vary across the surface of a lake, he said.

    The EPA is about to begin a more comprehensive study measuring methane emissions from 25 reservoirs in a region stretching from northern Indiana to northern Georgia, with sampling beginning next year, Beaulieu said.

    That study will help the EPA eventually include reservoir methane emissions in its total estimates of human-caused methane emissions.

    Until that and other studies are complete, scientists can only speculate on the impact hydropower is having on the climate.

    “We’re still in the very early days here of understanding how these systems work with respect to greenhouse gas production,” Harrison said.

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  9. Australia Blasted by Record Heat — Again

    Strange early-season temperatures again dogged sweaty Australians over the weekend, with Saturday’s continent-wide average maximum topping 97°F — a record for October.

    Spring heat waves that have been baking the continent in recent weeks are “consistent” with the modeled effects of global warming in Australia, said Tom Knutson, a National Oceanic and Atmospheric Administration climate modeler.

    But global warming alone couldn’t explain the unseasonably hot weather. It’s likely that climate change has juiced natural heat waves, raising their temperatures and worsening their effects, Knutson said.

    Temperature anomoloies on Saturday.
    Click image to enlarge. Credit: Australian Bureau of Meteorology

    Knutson led research, published a month ago in the annual extreme-weather issue of the Bulletin of the American Meteorological Society, that found human-caused global warming contributed about 1.5°F to Australia’s unusual temperatures in 2013. That was in addition to 1.2°F of additional heat, over and above typical temperatures, that was produced by natural variability. 

    Together, greenhouse gases and natural fluctuations created a scorching hot year Down Under that left previous records in its dust. The temperatures were so high last year that the Australian government was forced to develop new colors for its weather maps.

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    While Knutson hasn’t conducted any modeling to try to explain the most recent bouts of extreme Australian heat, he says a similar contribution from anthropogenic warming was likely, combined with a larger contribution from natural variability.

    “For the recent event,” Knutson says, “the contribution from natural internal variability I'm sure is much greater than the anthropogenic contribution.”

    Here’s a quick trip across some of Australia’s most sunscorched places of late, featuring pore-opening data provided to the Sydney Morning Herald and Australian Broadcasting Corporation by the Australian Bureau of Meteorology:

    Credit: Ars Electronica/flickr

    St. George, Queensland

    This agricultural outpost routinely experiences the types of furnace-mimicking temperatures for which southwestern Queensland, where the small town is located, is well known. But when the mercury topped out at more than 108°F on Sunday, the town broke its previous record for October heat.

    Wanarring, New South Wales

    The 100-odd resident of this outback village, 600 miles northwest of Sydney, endured a record-breaking eight consecutive days this month in which the mercury exceeded 95°F.

    Bidyanga, Western Australia

    Temperatures in this Aboriginal community in the Kimberley region exceeded 113°F on Oct. 9, which was two weeks earlier than that benchmark had been reached in recorded history. (113°F might sound like an odd benchmark, but it makes more sense once you realize it’s equivalent to 45 degrees Celsius, which is the temperature measurement of choice in Australia.)

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  10. Drying Amazon Could Be Major Carbon Concern

    The lungs of the planet are drying out, threatening to cause Earth to cough up some of its carbon reserves.

    The Amazon rainforest inhales massive amounts of carbon dioxide from the atmosphere, helping keep the globe’s carbon budget in balance (at least until human emissions started throwing that balance off). But as a new study shows, since 2000 drier conditions are causing a decrease in lung capacity. And if the Amazon’s breaths become more shallow, it’s possible a feedback loop could set in, further reducing lung capacity and throwing the carbon balance further out of whack.

    Aerial view of the Amazon rainforest near Manaus, the capital of the Brazilian state of Amazonas, Brazil.
    Credit: CIFOR/Flickr

    The study, published in the Proceedings of the National Academy of Sciences on Monday, shows that a decline in precipitation has contributed to less healthy vegetation since 2000.

    “It’s well-established fact that a large part of Amazon is drying. We’ve been able to link that decline in precipitation to a decline in greenness over the last 10 years,” said Thomas Hilker, lead author of the study and forestry expert at Oregon State University.

    Since 2000, rainfall has decreased by up to 25 percent across a vast swath of the southeastern Amazon, according to the new satellite analysis by Hilker. The cause of the decline in rainfall hasn’t been pinpointed, though deforestation and changes in atmospheric circulation are possible culprits.

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    The decrease mostly affected an area of tropical forest 12 times the size of California, as well as adjacent grasslands and other forest types. The browning of that area, which is in the southern Amazon, accounted for more than half the loss of greenness observed by satellites. While the decrease in greenness is comparatively small compared with the overall lushness of the rainforest, the impacts could be outsize.

    That’s because the amount of carbon the Amazon stores is staggering. An estimated 120 billion tons of carbon are stashed in its plants and soil. Much of that carbon gets there via the forest flora that suck carbon dioxide out of the atmosphere.

    Worldwide, “it essentially takes up 25 percent of global carbon cycle that vegetation is responsible for,” Hilker said. “It’s a huge carbon stock.”

    Dry years can lead to huge carbon losses. During a severe drought in 2005 — an El Niño year — the Amazon lost an estimated 1.6 gigatonnes of carbon, slightly less than Russia’s annual carbon dioxide emissions.

    Hilker and his colleagues identified El Niño years like 2005 as particularly “down” years for vegetation, with the opposite being true for La Niña years.

    Some future projections indicate that climate change could make “super” El Niños twice as likely, which could increase the odds of drought. Hilker cautioned that more research is needed to fully understand the connection between El Niño and drought, since his team only analyzed data covering 2000-2012. He also said that while the drought currently affecting Sao Paulo's water supplies certainly fits with the broader pattern, it wasn't included in the study itself so it was hard to draw any definitive conclusions.

    The study does note that because the poles are warming faster than the tropics, it could pull the band of rain that waters the Amazon and other parts of the tropics further north, increasing the odds of Amazonian drought and, with it, an uptick in carbon emissions.

    “An Amazon already responding to drought is big news for climate. Maybe a small part of that signal is actually due to deforestation, but that still implies a loss of forest productivity that influences how the Amazon forest impacts climate globally,” said Abigail Swann, a climate and ecosystems researcher at the University of Washington.

    The driving reason for the study is a longstanding disagreement between ground observations and satellite data, Hilker said. Ground observations at specific field stations have shown this drying trend. However, satellite data hasn’t provided as clear a picture, in part because of how cloudy the region is. By taking a new approach to processing that satellite data, Hilker’s analysis provides a clearer view through the clouds.

    “The authors are able to retrieve more data than before, which gives them greater statistical power to draw conclusions from,” Swann said, who wasn’t associated with the study.

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