Climate: What if Arctic sea ice doesn’t form in winter?

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Arctic sea ice is on a downward spiral. Visit this NASA Earth Observatory website for information on this image.

New models look at year-round ice-free conditions to find parallels with Pliocene epoch

By Summit Voice

FRISCO — As atmospheric concentrations of carbon dioxide start to hover around 400 parts per million, climate scientists have been looking back about 3 to 5 million years, to the Pliocene Epoch — the last time heat-trapping greenhouse gases were at a similar level.

But temperatures during the Pliocene were about 3.5 to 9 degrees Fahrenheit warmer than today and the sea level was 65 to 80 feet higher. Until now, scientists have assumed that there’s a time lag between atmospheric CO2 levels and the subsequent temperature increases that melt ice and drive ocean levels up. Continue reading

Global warming: 70 feet of sea level rise?

 2 to 3 feet of sea level rise expected this century

A relatively small increase in ocean temps could trigger a meltdown of the West Antarctic ice shelf, resulting in a significant rise in sea levels.

By Summit Voice

SUMMIT COUNTY — Scientists continue to grapple with the question of how global warming will affect sea levels, looking at evidence of past climate change to try and determine how the future will play out.

In one of the latest studies, researchers from Rutgers University looked at rock and soil cores in Virginia, Eniwetok Atoll in the Pacific and New Zealand, dating back to the Pliocene epoch, 2.7 million to 3.2 million years ago — the last time concentrations of carbon dioxide in the atmosphere were as high as they are now, and atmospheric temperatures were 2 degrees C higher than they are now.

“The natural state of the earth with present carbon dioxide levels is one with sea levels about 20 meters higher than at present,” said Kenneth G. Miller, professor of earth and planetary sciences in the School of Arts and Sciences at Rutgers University. “The current trajectory for the 21st century global rise of sea level is 2 to 3 feet (0.8 to1 meter) due to warming of the oceans, partial melting of mountain glaciers, and partial melting of Greenland and Antarctica.” Continue reading

Fossilized coral reefs offer global warming clues

Coral reef biodiversity likely to take a big climate change hit.

Free-floating coral likely to survive; structured reefs will probably disappear

By Summit Voice

SUMMIT COUNTY — Fossilized coral reefs more than 2 million years old are providing some clues about how global warming may affect existing reefs.

Scientists from the University of Miami are analyzing reefs from Pliocene era, when carbon dioxide levels and mean global temperatures were similar to conditions expected in the next 100 years.

“If the coming century truly is a return to the Pliocene conditions, corals will likely survive, while well-developed reefs may not,” said University of Miami geology professor James Klaus. “This could be detrimental to the fish and marine species that rely on the reef structure for their habitat.” Continue reading

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