Glaciers and ‘zombie ice’: study finds melting on both ends of Earth

As Earth’s ice melts, sea levels will rise, a prediction that began to come true long ago, when humans began pumping massive amounts of greenhouse gases into the atmosphere and industrial civilization was just emerging. However, the timetable for sea level rise is not entirely clear, nor do we really know how close our coastal cities are to facing damage from simultaneous flooding or high tides.

Now, a new study sheds light on a possible — and even possible — pathway by which sea-level rise could play a role on Earth and flood our coastal cities.

The first study — published in the journal Nature Geoscience — involved Thwaites Glacier, a natural wonder in West Antarctica about the size of Florida. As the widest glacier in the world, it has been nicknamed the “doomsday glacier” – because if it collapsed, the ensuing rise in global sea levels would displace millions of people. Researchers have determined that Thwaites Glacier is melting at dangerous levels, and this new study sheds light on the magnitude of the problem.

“Our greenhouse gas emissions are hitting the climate system with a figurative hammer.”

The researchers studied imprints on the seabed to determine the movement of Thwaites Glacier over the past century; therefore, they determined that the glacier shrank about 1.3 miles per year during this period. That’s twice the rate of contraction we see today, which means that while the current rate of melting isn’t unprecedented, the ice sheet is indeed capable of melting so fast that the Thwaites Glacier itself would collapse. If all the ice present in the upper Thwaites Glacier Basin melted, global sea levels would rise by more than two feet.

Dr Anna Wåhlin, professor of physical oceanography in Gothenburg, Sweden, said: “About 100 years ago, it was receding faster than it is now… You could say that’s good news because things are not that bad now compared to the past.” The university and the study’s co-authors told NBC News. “But you could also say it’s bad news because it could happen again.”

The second study, published in the journal Nature Climate Change, was led by Dr. Jason Box, a glaciologist at the Geological Survey of Denmark and Greenland. Greenland’s rapidly melting ice sheet will raise global sea levels by at least 10.6 inches (27 centimeters), the study found. That’s more than twice as fast than experts previously thought, and it’s propelled by “zombie ice,” or smaller bodies of ice that are still attached to the larger body, but are not constantly being fed by snow. Doomed to melt by the parent glacier.

As study co-author Dr. William Colgan explained to The Associated Press, “It’s dead ice. It melts and disappears from the ice sheet. No matter what climate (emissions) scenario we’re in, this ice has been destroyed by Ship to the ocean and take it now.”

That puts the new study in stark contrast to the Intergovernmental Panel on Climate Change (IPCC), a United Nations agency focused on tackling climate change. The IPCC last year estimated that by 2100, melting Greenland’s ice will only raise sea levels by 2 to 5 inches.

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Dr. Jim Hansen, director of the Climate Science, Awareness and Solutions Program at Columbia University’s Earth Institute, told Salon by email that the latest paper is an “incremental pushback” by scientists “to combat the IPCC’s institutionalized scientific silence.”

“Failed to properly warn the public, or even provide a little advice on the policies needed, for decades, the IPCC continues to pretend it is possible to keep global warming below 1.5°C and set emissions reduction targets,” Hansen explained. Climate science tells us that we have entered dangerous levels of greenhouse gases whose consequences will far exceed 10 inches of sea level rise.”

Sarah Pralle, Ph.D., an associate professor of political science at Syracuse University who specializes in environmental politics and policy, climate change and energy, also told Salon that the new research suggests that “our previous climate change impact models may have underestimated the magnitude and impact of major climate hazards such as sea level rise.” schedule.”

Dr. William Sweet, a scientist with the National Oceanic and Atmospheric Administration (NOAA), presented Sharon with the agency’s technical report on sea level rise. The report, released in February, appeared to reinforce concerns raised by two recent studies. The NOAA report predicts that sea levels along the US coastline will rise from 10 inches to 12 inches over the next 30 years, although this is an average figure. Along the East Coast, a rise of 10 to 14 inches is expected; for the West Coast, a rise of 4 to 8 inches is expected; and for the Gulf Coast, a rise of 14 to 18 inches is expected.

Needless to say, major metropolises from San Francisco to New York City could be severely submerged.

“Sea level rise is already affecting us here and now, and it will continue to intensify for decades to come.”

“These studies provide additional evidence for future sea level rise that the public needs to be aware of,” Sweet wrote in a letter to Sharon. “Sea level rise is already affecting us here and now, and it will continue to intensify for decades to come.” In the words of Dr. Ken Caldeira, senior scientist emeritus at the Carnegie Institution for Science, “For those who have been studying Earth’s geological past For climate change people, this type of research is not surprising.”

“Climate change studies in past geology paint a picture of a world changing much faster and more strongly than most modern climate models predict,” Caldera believes. “Our greenhouse gases Emissions are hitting the climate system with a figurative hammer. We have to expect the unexpected. If we think what is predicted is what we have to worry about, then we are living in a fantasy land. We are intervening in a “this system” Much more complex than any of our models. We can be sure that many things that we cannot predict will happen. “

Some scientists have criticized how the media presented the studies to the public.

Dr. Michael E. Mann, Distinguished Professor of Atmospheric Sciences at Penn State, wrote to Sharon about the new studies, where he discussed them with Dr. Richard Alley, “one of the world’s leading glaciologists.” They argue that the new study doesn’t change what we know about Thwaites Glacier, despite “suffocating headlines in NBC News article” (“‘Doomsday’ glaciers may melt faster than previously thought”).

“As Richard told me, ‘This information doesn’t really support any plausible claims about ice sheet instability or stability, there’s no fundamental change in our understanding,'” Mann explained. “To be clear, our current understanding is sufficient to be of concern. This suggests that we may be very close to locking in enough warming that we lost most of the West Antarctic Ice Sheet, enough ice to give us 10 feet or more of ice. A lot of ocean levels will eventually rise. But we know going in. This research doesn’t change our understanding in that regard.

Regarding the Greenland study, Mann again urged caution in the media covering it.

“This is a useful study, and the main conclusion — that the Greenland ice sheet could cause a foot rise in sea levels — seems entirely plausible,” Mann wrote. “But there’s also some misleading coverage here. The authors (as in the AP article) suggest that this will happen within this century, but they don’t actually provide any support for it, so it seems like some of their public commentary is lagging behind on what their science actually shows.”

Dr. Kevin Trenberth, a member of the Climate Analysis Section at NCAR’s National Center for Atmospheric Research, was critical of the way the reports were discussed publicly.

“The statements made about the two studies are misleading at best and often false,” Trembers wrote in a letter to Sharon. “Land-based ice melt has huge impact on sea level rise. Greenland study doesn’t set a timeline for ice loss: certainly not this century, but maybe [two] century. So it’s really a major long-term issue, but a lot of what’s been said in the report is wrong. “

He added: “The Thwaites paper is interesting and provides a mechanism for increasing glacier flow. It is less clear what it means for sea level rise and on what time scale. Again, this is the main long-term question, but …and many more buts.”

Some of the ice in question is already floating so it doesn’t affect sea levels when it melts, Trembos mentioned. It also doesn’t take into account “other things in other directions, such as increased snowfall in Antarctica, which would remove water from the ocean. So people should be concerned and welcome more and more information and understanding, but there are many other reasons why more How worried.”

Pointing to Pakistan as real evidence of climate-change-related flooding, Trenberth wrote: “The extensive flooding in Pakistan is partly the result of heavy rains, but also the result of rising sea levels that prevent land water from being lost.”

Some of the scientists Sharon spoke with also discussed potential policy solutions to the problem of human climate change.

“Policy makers and political leaders need to take heed and intensify and accelerate their responses to climate threats, giving us the best chance of avoiding the worst impacts of climate change,” Pralle argues. “Some of these changes will happen whether we reduce emissions or not, so we also need to adapt to changes that are ‘ripe’, so to speak. At the same time, we shouldn’t let stories/studies like this make us despair. Our commitment to reducing greenhouse gases Everything the emissions do helps, and the difference between some warming and a lot of warming is huge in terms of the scale and extent of the damage.”

Hansen specifically suggested raising the price of carbon products, noting that “economic science tells us we’re not going to start solving this problem until we have a steady increase in carbon prices.” He doesn’t think that will happen because “our politicians Don’t have the guts to do that, even if there are ways (carbon fees and dividends) to benefit most people economically. They’d prefer to subsidize this or that, which would have little impact on global emissions.”

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