Tag: sea level rise

Climate: Antarctic ice shelf retreat may be irreversible

Yes, there is still lots of ice in Antarctica, but it's melting faster than ever. bberwyn photo.
Yes, there is still lots of ice in Antarctica, but it’s melting faster than ever. @bberwyn photo.

ESA satellites offer clues about climate change consequences

Staff Report

An analysis of data from European Space Agency satellites shows that Antarctic ice shelves may be losing their buttressing role as they get thinner and retreat inland.

The findings, announced in February, used ice velocity data to show that there is a critical tipping point at which the shelves act like a restraining band, holding back the the ice that flows toward the sea. In a dramatic press release, the ESA said that, if the ice is lost, it could be “point of no return” for Antarctica’s ice.

The ice shelves are huge and losing them would have serious implications for global climate, speeding the rise of sea level. The Ross Ice Shelf, for example, is the size of Spain and towers hundreds of meters above sea level. Continue reading “Climate: Antarctic ice shelf retreat may be irreversible”

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Crumbling Antarctic ice sheets could speed sea level rise

Fifty feet in 500 years?

Mountains of the Antarctic Sound.
New climate modeling suggests more significant melting of the Antarctic ice sheets and ice shelves driven by atmospheric warming. @bberwyn photo.

Staff Report

The edges of Antarctic ice sheets may crumble and collapse much faster than most existing climate models suggest, potentially raising global sea level by as much as 50 feet in the next 500 years, according to researchers from Penn State and University of Massachusetts, Amherst.

The scientists added new, previously underestimated processes to their projection after studying the role of Antarctic ice melting during the warm Pliocene era, about 3 million years ago when sea level rose by as much as 30 to 60 feet. Continue reading “Crumbling Antarctic ice sheets could speed sea level rise”

Climate: Jet stream shifts may speed Greenland meltdown

More sea level woes ahead?

Melting on the surface of the Greenland Ice Sheet.
Melting on the surface of the Greenland Ice Sheet. @bberwyn photo.
How will global warming affect the flow of the jet stream?
How will global warming affect the flow of the jet stream?

Staff Report

Scientists are tracking yet another global warming feedback mechanism that will have dire consequences for coastal communities around the world. Melting sea ice and overall rapid warming in the Arctic are factors in the development of so-called blocking high pressure systems — air masses spinning clockwise that block cold, dry Canadian air from reaching Greenland.

The highs tend to enhance the flow of warm, moist air over Greenland, contributing to increased extreme heat events and surface ice melting, according to the study. That circulation pattern leads to more melting of the Greenland Ice Sheet, according to new research published online in the Journal of Climate last month, co-authored by Jennifer Francis, one of the pioneers in studying how global warming is affecting the jet stream. Continue reading “Climate: Jet stream shifts may speed Greenland meltdown”

Climate: New study shows how warm ocean currents affect Antarctic ice shelves

Erosion from beneath could lead to more sea-level rise

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If floating Antarctic ice sheets disintegrate, land-based glaciers and ice sheets will flow much faster to the sea, speeding sea level rise. @bberwyn photo.

Staff Report

Oceans warming under a thickening blanket of greenhouse gases are licking at the edge of Antarctica and carving new channels in the bottom of ice shelves all around the frozen continent, researchers said this week in a new study led by scientists with the National Snow and Ice Data Center.

Those channels, characterized as “upside-down rivers” by the scientists, may make the ice shelves more prone to collapsing, which could speed up the flow of ice and the increase the rate of sea-level rise. Overall, some Antarctic ice sheets have thinned by about 18 percent and the rate of melting is accelerating, other research shows.

The findings, published in Nature Geoscience, are based on detailed photography and laser measurements showing that the basal channels also leave traces on the surface of the ice sheets. Continue reading “Climate: New study shows how warm ocean currents affect Antarctic ice shelves”

Antarctic ice sheets may be more sensitive to CO2 than we thought

New ice core study helps pinpoint global warming impacts

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Ice core samples suggest that Antarctic ice sheets may see big changes at lower levels of CO2 than previously thought. @bberwyn photo.

Staff Report

After studying a new ice core sample from McMurdo Sound, researchers say they’re a bit closer to one of the holy grails of climate science — understanding how Antarctic ice sheets will respond to increasing concentrations of atmospheric carbon dioxide.

The study, published in the Proceedings of the National Academy of Sciences, suggests that big changes could happen at lower levels of CO2 than previously thought.

The scientists looked at a 3,735-foot sediment core to reconstruct the Antarctic ice sheets’ history in an effort to create a climate model that mirrors conditions during the Miocene Era, when atmospheric CO2 levels were slightly higher, at 500 parts per million, than the 400 ppm level reached just last year, and global average temperatures were about 3 to 4 degrees Celsius higher than today. Continue reading “Antarctic ice sheets may be more sensitive to CO2 than we thought”

Policy makers must take long-term view of climate change

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Impacts of greenhouse gas emissions will last for thousands of years.

‘It is high time that this essential irreversibility is placed into the focus of policy-makers’

Staff Report

Today’s debates about global warming impacts are much too shortsighted, according to a new analysis, which warns that, at the current rate of greenhouse gas emissions, the Earth is likely to suffer irreparable damage that could last tens of thousands of years.

“Much of the carbon we are putting in the air from burning fossil fuels will stay there for thousands of years – and some of it will be there for more than 100,000 years,” said Oregon State University paleoclimatologist Peter Clark. “People need to understand that the effects of climate change on the planet won’t go away, at least not for thousands of generations,” said Clark, lead author of the article. Continue reading “Policy makers must take long-term view of climate change”

Climate study says West Antarctic Ice Sheet could melt quickly

The ice fields of Antarctica
How quickly will the West Antarctic Ice Sheet melt away under global warming? @bberwyn photo.

‘All signs suggest the ice from West Antarctica could disappear relatively quickly …’

Staff Report

An in-depth survey of Antarctica’s rugged Ellsworth Mountains suggests that the West Antarctic Ice Sheet could melt quickly under the influence of global warming, potentially raising global sea level by three meters.

“It is possible that the ice sheet has passed the point of no return and, if so, the big question is how much will go and how much will sea levels rise,” said Professor John Woodward, of the University of Northumbria. Continue reading “Climate study says West Antarctic Ice Sheet could melt quickly”