Sea Levels Could Rise More Than 6 Feet by Century’s End, Experts Warn

Residents of Manila cross floodwaters after torrential rains caused heavy flooding in the Philippines on August 8, 2012. The Philippines are among the low-lying nations most at risk of flooding from rising sea levels. Visual: Dondi Tawatao / Getty Images

Among the many dangerous consequences of anthropogenic climate change is sea level rise, driven in part by added water from melting ice sheets and glaciers, and the expansion of existing seawater as it warms. According to a study published Monday in the Proceedings of the National Academy of Sciences, ice sheets in Greenland and Antarctica might be melting faster than once predicted, and, if emissions proceed unchecked, sea levels could plausibly rise 6.5 feet by 2100.

In contrast, the United Nations’ Intergovernmental Panel on Climate Change estimated in 2014 that the worst case warming scenario would raise sea levels by only around 1.7 feet to 3.2 feet over the same time period. At the time, the group’s report drew criticism for being too conservative in its predictions.

Using a method known as structured expert judgement, the researchers of the new study coordinated 22 experts on sea level rise and ice sheet dynamics, asked them to make predictions on sea level rise in several different warming scenarios, and combined their responses, taking into account how certain each scientist was about their own estimations.

If the Earth warms by 5 degrees Celsius — the so-called “business as usual” scenario in which carbon emissions continue unchecked as the population grows — the experts estimated an average of 1.6 feet of sea level rise due to melting ice sheets by 2100, but with a 5 percent chance that total sea level rise could exceed 6.5 feet.

“If we see something like that in the next 80 years,” lead author Jonathan Bamber of the University of Bristol told New Scientist, “we are looking at social breakdown on scales that are pretty unimaginable.” A rise of this magnitude could spell disaster for some of the world’s largest coastal cities including New York, Miami, Shanghai, Jakarta, Osaka, and Rio de Janeiro, as well as many small Pacific island nations like the Maldives, the Marshall Islands, and Tuvalu. The study estimates some 187 million people would be displaced.

While the researchers acknowledged in the study the “deep uncertainties” in making predictions about processes as complex as ice sheet dynamics several decades out, they hope their results will be “a source of complementary insights into the current state of knowledge.”

“This is part of the effort to do the best we can to provide information to the public and policymakers when we really can’t meet the normal standards,” Richard Alley, a geologist at Pennsylvania State University who was not involved in the research, told NBC.

Also in the news:

• More than a dozen child health research centers now face an uncertain future, as the U.S. Environmental Protection Agency (EPA) plans to cut off funding at the end of July. The country’s 13 Children’s Environmental Health and Disease Prevention Research Centers have historically been jointly funded by the EPA and the Department of Health and Human Services’ National Institute of Environmental Health Sciences (NIEHS). As first reported by Nature last week, one such center in New York City has tracked the effects of environmental pollutants on children since 1998, with long-term studies providing valuable insight into how early environmental exposures can affect health later in life. Research conducted by the center, for instance, suggests that the pesticide chlorpyrifos is harmful to child brain development — impacting Hawaii’s decision to ban its use in 2018. While the NIEHS has said they will focus on outreach surrounding the centers’ completed research, they emphasize that they cannot pick up the slack created by the EPA’s decision. (E&E News)

• Building managers have long acknowledged that office air conditioning settings are designed with male body temperatures in mind. The so-called “battle of the thermostat,” as The New York Times notes, means that most women keep a sweater handy at the office. But a study published in the journal PLOS One this week suggests that the issue might cause more than the occasional case of goosebumps. The researchers, studying a group of more 500 college students in Berlin, found that women performed cognitive tasks, such as math problems, significantly better if room temperatures were even slightly warmer. They also noted that men’s math performance dropped slightly as temperatures rose but “the increase in female performance in response to higher temperature” was significantly larger than corresponding decrease in male test results. As an example, an increase of one degree Celsius could improve women’s test scores by nearly 2 percent. Scientists suggested that in “gender-balanced” workplaces a more equitable temperature setting could be used to improve worker productivity. (The Atlantic)

• On Monday, the International System of Units officially adopted new definitions for four base units — the kilogram, ampere, kelvin, and mole. For more than 130 years, the world’s definition of a kilogram was based on a physical object housed in a subterranean vault on the outskirts of Paris: a gleaming cylinder of 90 percent platinum and 10 percent iridium known as “Le Grand K.” The unit had a tendency to shift over the years as the cylinder gained mass from airborne contaminants and loss mass via scratches and deep cleanings. Going forward, the world’s unit of mass will be defined not by a piece of metal, but by a fundamental property of nature known as Planck’s constant, which relates the energy of a particle of light to its frequency. “Unlike a physical object, a fundamental constant doesn’t change,” Stephan Schlamminger, a physicist at the National Institute of Standards and Technology in Gaithersburg, Maryland, told The Los Angeles Times. “Now a kilogram will have the same mass whether you are on Earth, on Mars, or in the Andromeda galaxy.” (The Los Angeles Times)

• A study published Wednesday in Nature attributes a mysterious spike in emissions of the banned ozone-depleting gas trichlorofluoromethane, or CFC-11, to two provinces in eastern China, likely from new industrial manufacturing. Once used to blow polyurethane into rigid insulating foam for use in refrigerators and other consumer goods, CFC-11, along with other chlorofluorocarbons (CFCs), was outlawed under the Montreal Protocol, a 1987 treaty to phase out production of CFCs internationally by 2010, after their ozone-depleting effects were discovered. Global monitoring showed that atmospheric levels of all CFCs were initially in steady decline, but in 2012 the global drop slowed significantly, and levels of CFC-11 begun once again to increase. Now researchers have zeroed in on one likely source of 40 to 60 percent of the CFC-11 emissions: the Chinese provinces of Shandong and Hebei. Investigations by the international Environmental Investigation Agency and Chinese authorities also discovered evidence of illegal CFC-11 use in manufacturing. The study found no evidence of emissions elsewhere in China. (Science News)

• Despite decades of overfishing, Mexico’s Gulf of California, also known as the Sea of Cortez, remains one of the country’s most productive fisheries. But in the northern reaches of the Gulf, communities of lifelong anglers are idle — caught up in a tangled story of endangered porpoises, haphazard government oversight, and dubious Chinese medicine, among other crisscrossing narratives. The porpoise is the vaquita, a rare species endemic to the northern Gulf and thought by some experts to be down to 20 or fewer individuals. National and international efforts to save the vaquita include closing off large expanses of sea to fishermen who have long made their livelihoods in the region. They were promised compensation payments, but many of them now say those payments have begun to dry up. And while they bide their time on shore, they must watch as organized poachers flagrantly plumb the very same waters in search of the prized (and distressed) totoaba fish, whose swim bladder is coveted as a fertility treatment, among other remedies, in China. Meanwhile, all sea life in the region is at risk from a thicket of illegal gillnets, many abandoned, that litter these waters. The collision of science, conservation, commerce, and regulation is far from being resolved: “These are dark days for those of us who fish legally,” one fisherman told Undark. “By law we cannot work, but those who fish illegally continue to do it, embargo or not.” (Undark)

• And finally: Washingtonians now have a new, environmentally friendly option for the afterlife. On Tuesday the state became the first in the U.S. to approve of composting as an alternative to burial and cremation for human remains. Starting in May 2020, licensed facilities in the Evergreen State can offer “natural organic reduction,” a procedure conceived by designer and entrepreneur Katrina Spade. Taking cues from a common practice for disposing of livestock, Spade found a way to coax human corpses into biodegrading in a matter of weeks. The procedure involves tumbling the corpse in a rotating compartment filled with woodchips, alfalfa, and straw. The resulting soil — about two wheelbarrows’ worth — is then returned to loved ones, who can spread it like ashes, or use it to grow a plant or tree. Some Washingtonians, however, pushed back against the new law. Senator Jamie Pedersen, who sponsored the legislation, told the Associated Press that he received angry objections from people saying the idea was undignified and disgusting. But the lawmaker insists that the composting process will be respectful. No one’s “going to toss Uncle Henry out in the backyard and cover him with food scraps,” said Pedersen. (Associated Press)