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Lakes on Greenland Ice Sheet Drain in Chain Reaction, Destabilizing Sheet and Raising Sea Levels
A research team led by the University of Cambridge found that the lakes of meltwater that form on the ice sheet in the summer drain in a chain reaction that increases the flow of the ice sheet, destabilizing it and increasing sea level rise, the University of Cambridge reported in a press release.
It had long been known that these lakes could drain quickly on an individual basis. They can last months, then drain through more than one kilometer (approximately 0.621 miles) of ice within hours.
However, this study used a combination of observation and three-dimensional modeling to show that the lakes do not drain in isolation. Instead, the melting of one lake can trigger the melting of lakes up to 80 kilometers (approximately 49.71 miles) away.
The process begins when a lake drains and the water it contained ends up on the bottom of the ice sheet. This causes the sheet to flow faster, which destabilizes it and leads to the formation of more fractures. Other lakes then drain through these new fractures in a chain reaction that can speed the flow of the ice sheet by up to 400 percent.
A model of the lake-melting chain-reaction process. Nature Communications
Researchers observed 124 lakes drain within a span of five days, and found evidence for crevices opening 135 kilometers (approximately 83.9 miles) inland from the ice sheet's edge, which is farther than thought possible.
The study therefore contradicts the findings of the Fifth Assessment Report by the Intergovernmental Panel on Climate Change, published in 2014, which held that melt water on the surface of the ice sheet did not impact its flow.
"This growing network of melt lakes, which currently extends more than 100 kilometres inland and reaches elevations as high as 2,000 metres above sea level, poses a threat for the long-term stability of the Greenland ice sheet," the study's lead author and member of Cambridge's Scott Polar Research Institute Dr. Poul Christoffersen said in the press release.
This isn't the first study in recent years to suggest the Greenland ice sheet is in more trouble than previously believed. In 2016, scientists found the ice sheet was melting 7 percent faster than they had thought.
While the Polar Portal reported that the ice sheet actually gained a small amount of mass in 2017 due to heavy winter snows and a cool summer, the National Oceanic and Atmospheric Administration calculated that the sheet could only regain the mass it has lost since 2002 after 80 years like this one.
According to Global Citizen, the ice sheet, which is seven times the size of the United Kingdom and two miles thick, is currently contributing to global sea level rise at a rate of one millimeter (approximately 0.04 inches) per year. If all the ice in the sheet were to melt, it would raise sea levels by more than 20 feet.
This is unlikely to happen any time soon, but that doesn't mean there's nothing to worry about.
"When we say the ice sheet is melting faster, no one saying it's all going to melt in next decade or the next 100 years or even the next 1,000 years but it doesn't all have to melt for more people to be in danger," Dr. Joe Cook, a glacial microbiologist at Sheffield University, told Global Citizen. "Only a small amount has to melt to threaten millions in coastal communities around world."
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‘Companies Should Not Be Allowed to Use Hazardous Ingredients in Products People Use’: Michelle Pfeiffer Speaks Up for Safer Cosmetics
The beauty products we put on our skin can have important consequences for our health. Just this March, the U.S. Food and Drug Administration (FDA) warned that some Claire's cosmetics had tested positive for asbestos. But the FDA could only issue a warning, not a recall, because current law does not empower the agency to do so.
Michelle Pfeiffer wants to change that.
The actress and Environmental Working Group (EWG) board member was spotted on Capitol Hill Thursday lobbying lawmakers on behalf of a bill that would increase oversight of the cosmetics industry, The Washington Post reported.
By Julia Conley
Scientists at the United Nations' intergovernmental body focusing on biodiversity sounded alarms earlier this month with its report on the looming potential extinction of one million species — but few heard their calls, according to a German newspaper report.
The climate crisis is a major concern for American voters with nearly 40 percent reporting the issue will help determine how they cast their ballots in the upcoming 2020 presidential election, according to a report compiled by the Yale Program on Climate Change Communication.
Of more than 1,000 registered voters surveyed on global warming, climate and energy policies, as well as personal and collective action, 38 percent said that a candidate's position on climate change is "very important" when it comes to determining who will win their vote. Overall, democratic candidates are under more pressure to provide green solutions as part of their campaign promises with 64 percent of Democrat voters saying they prioritize the issue compared with just 34 percent of Independents and 12 percent of Republicans.
President Donald Trump has agreed to sign a $19.1 billion disaster relief bill that will help Americans still recovering from the flooding, hurricanes and wildfires that have devastated parts of the country in the past two years. Senate Republicans said they struck a deal with the president to approve the measure, despite the fact that it did not include the funding he wanted for the U.S.-Mexican border, CNN reported.
"The U.S. Senate has just approved a 19 Billion Dollar Disaster Relief Bill, with my total approval. Great!" the president tweeted Thursday.