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Antarctic Ice-Sheet Collapse Could Trigger Rapid Sea-Level Rise

A study published in Nature finds that Antarctic ice-sheet collapse driven by greenhouse gas emissions could double the sea-level rise predicted for this century—from 3.2 feet according to a three-year-old United Nations estimate to upward of 6.5 feet by 2100. The research builds on the work of other recent studies pointing to an irreversible melting of the West Antarctic Ice Sheet as a result of human-caused climate change, but it suggests that sea-level rise could shift into high gear, becoming anexistential problem for low-lying coastal cities within the lifespan of current generations of people absent rapid emissions cuts to contain warming to within 2 degrees Celsius above pre-industrial levels.

The study findings are based on new computer simulations showing that warming of the atmosphere and the oceans makes the ice sheetvulnerable from above and below. By the 2050s, according to the simulations, the ice sheet would begin disintegrating, and parts of the higher, colder ice sheet of the East Antarctica would also eventually fall apart.

The climate model developed by the study authors accounts for ice loss through complex processes, including “hydro fracturing,” a process whereby meltwater on ice shelves causes huge chunks of ice to fall into the water. By reflecting these processes, the researchers were able tosimulate past geological periods in which sea levels were higher than today but carbon dioxide levels were about the same or even much lower. They projected sea-level rise using versions of their model that best simulated these periods—the first model to do so.

Why is reconstruction of past rises in sea level important? High sea levels during warm intervals, such as the Pliocene and Eemian eras, imply that the Antarctic Ice Sheet is highly sensitive to climate warming.

“In the past, when global average temperatures were only slightly warmer than today, sea levels were much higher,” said study co-author Rob DeConto, a geoscientist at the University of Massachusetts Amherst. “At the high end, the worst-case scenarios, with sort of business as usual greenhouse gas emissions … we will literally be remapping coastlines. North America is kind of a bull’s eye for impacts of sea level rise if it’s the west Antarctic part of Antarctica that loses the ice first. That’s the place that we’re worried about losing ice first.”

Study: Health Impacts of Climate Change Significant

The public health impacts of climate change on people in the United Stateswill be significant and wide ranging, according to a study by the U.S. Global Change Research Program. The study reflects data and analysis from eight agencies, led by the U.S. Environmental Protection Agency (EPA), the Department of Health and Human Services, and the National Oceanic and Atmospheric Administration, which said that “Nearly all of the health threats, from increases in our exposure to excessive heat to more frequent, severe or longer-lasting extreme weather events to degraded air quality to diseases transmitted through food, water, and vectors (such as ticks and mosquitoes)—even stresses to our mental health—are expected to worsen.”

Without rapid efforts to combat climate change, extreme heat alone will cause more than 11,000 additional deaths in the summer of 2030, the study suggests. Other risks include worsening allergy and asthma conditions and increased exposure of food to certain pathogens and toxins. But climate change will not just exacerbate existing risks—it will give rise to unprecedented health problems such as the spread of Lyme disease in new locations.

“Every American is vulnerable to the health impacts associated with climate change,” said White House Science Adviser John Holdren, adding that “Some are more vulnerable than others.”

These groups include pregnant women, children, the elderly, low-income people, communities of color and those with disabilities or pre-existing medical conditions.

Release of the findings coincided with the Obama administration’s announcement of several new initiatives to address those impacts, such as expanding the scope of a presidential task force on childhood risks to include climate change (subscription). Other actions include creating climate change and health curricula for schools and establishing a Climate-Ready Tribes and Territories Initiative, which will provide funding for prevention of climate-change-related health problems.

Paris Deal: Largest Polluters Agree to Sign

Last week, the White House announced that the United States and Chinawill sign the Paris Agreement to combat global climate change at a United Nations ceremony April 22.

“Our cooperation and our joint statements were critical in arriving at the Paris agreement, and our two countries have agreed that we will not only sign the agreement on the first day possible, but we’re committing to formally join it as soon as possible this year,” said President Obama. “And we urge other countries to do the same.”

Brian Deese, senior adviser to President Obama, said swift approval of the agreement would keep emissions reductions efforts on track. Noting congressional action last year to extend tax credits for wind and solar energy and asserting firm legal ground for the Clean Power Plan, Deese said that the United States has both “the capacity and the tools” to meet its international commitments.

United Nations Secretary-General Ban Ki-moon has said that he expects at least 120 countries will sign the agreement at the April 22 ceremony at the U.N.’s New York headquarters. To enter into force, that agreement needs at least 55 countries representing at least 55 percent of global emissions to formally accede to it. So far, three Pacific island nations have ratified the deal.

The Climate Post offers a rundown of the week in climate and energy news. It is produced each Thursday by Duke University’s Nicholas Institute for Environmental Policy Solutions.

Comments

  1. george moscatello
    April 13, 10:59 pm

    they make so much mention about co2 and that they believe it attributes to the warming of our planets surface but they don’t consider the ozone hole which allows a tremendous amount of unfiltered, lethal radiation,to enter our atmosphere and hit our planets surface,melting all of our planets ice ,which has nothing to do at all, with Co2.Co2 is absorbed by all the oceans on our planet and all the vegetation covering our planet ,where-by depleting the atmosphere of co2.the ozone layer above Antarctica, was always filtering out the suns radiation ,allowing a minimal amount of radiation to enter our atmosphere and hit our planets surface ,until the ozone layer got destroyed, by heavy concentrations of chlorine molecules, in the Antarctic atmosphere ,resulting in a hole developing in the ozone layer above Antarctica ,resulting in a tremendous amount of unfiltered ,lethal radiation from our sun,entering our atmosphere and hitting our planets surface and melting all of earths ice.the scientists have been attributing our planets heating to what they refer to as ,the”green-house effect”where-by, there claiming that the suns radiation, after bouncing off of our planets surface ,gets trapped in the atmosphere by Co2 ,heating the atmosphere and heating our planets surface ,melting our planets ice.the scientists were led to arriving at this green-house effect because they observed that the suns radiation ,after bouncing off of our planet`s surface was taking very long to pass through our atmosphere and go back out into space and they believed the radiation was getting trapped in the atmosphere by carbon dioxide and they refered to this phenomenon as the green-house effect,in which case Co2 would be trapping the suns radiation in the atmosphere.the scientists didn’t take into consideration ,that on account of the destruction of the ozone layer,resulting in a hole developing in the ozone layer,a tremendous amount more of unfiltered lethal radiation ,was entering our atmosphere through this opening and hitting our planets surface and melting all of earths ice.back in October 2015 the hole in the ozone layer was 10.9million square miles in diameter ,which is a larger square area than the entire north American continent.As the result of the destruction of the ozone layer ,where-by theres been a hole in the layer for decades,a tremendous amount of more unfiltered lethal radiation has been coming through the hole in the ozone layer and entering our atmosphere and hitting our planets surface .the scientists believe the radiation after bouncing off of earth is being trapped in the atmosphere by co2 and there not considering that theres just so much more radiation coming through the hole in the ozone layer,that its just taking longer for the radiation to go back out into space after bouncing off of our planets surface.when there was less it took a certain length of time but now theres 60 to 70% more so it would obviously take longer to go back into space after bouncing off of our planets surface.its not being trapped .theres just so much more that its taking longer.glad to share my conviction.