Oceanography

Ancient carbon trapped in Arctic permafrost is extremely sensitive to sunlight and can release climate-warming carbon dioxide gas into the atmosphere faster than previously thought if exposed to the surface when long-frozen soils melt and collapse..

They studied places in Arctic Alaska where permafrost is melting and is causing the overlying land surface to collapse, forming erosional holes and landslides and exposing long-buried soils to sunlight, and found that sunlight increases bacterial conversion of exposed soil carbon into carbon dioxide gas by at least 40 percent compared to carbon that remains in the dark.


There are projections that coral reefs will decline due to global warming but evolution disagrees. A number of coral species survive at seawater temperatures far higher than estimates for the tropics during the next century. 

We associate coral reefs with tropical seas of around 28 degrees so in that mindset even slight warming can have devastating effects on corals. But in the Arabian/Persian Gulf, corals survive seawater temperatures of up to 36 degrees Celsius every summer, heat levels that would kill corals elsewhere. Corals have adapted. 


A new study details changes in Earth's climate from more than 100,000 years ago and indicates that the last interglacial, the term for the periods between "ice ages", was warmer than previously thought. 

The research findings also indicate that melting of the massive West Antarctic ice sheet may have contributed more to sea-level rise at that time than melting of the Greenland ice sheet.


Arctic sea ice has not only declined over the past decade but has also become distinctly thinner and younger - mainly thin, first-year ice floes which are extensively covered with melt ponds in the summer months where once meter-thick, multi-year ice used to float.

Researchers have now measured the light transmission through the Arctic sea ice for the first time on a large scale, enabling them to quantify consequences of this change. They come to the conclusion that in places where melt water collects on the ice, far more sunlight and therefore energy is able to penetrate the ice than is the case for white ice without ponds.


Reconstructions of atmospheric CO2 concentrations and sea level over the past 40 million years show that greenhouse gas concentrations similar to the present (nearly 400 parts per million) were associated with sea levels at least nine meters above current levels. 

They determined the 'natural equilibrium' sea level for CO2 concentrations ranging between ice-age values of 180 parts per million and ice-free values of more than 1,000 parts per million.  Of course, it takes centuries for equilibrium to be reached so they don't try to predict any sea level value for the coming century but it can help illustrate what sea level might be expected if climate were stabilized at a certain CO2 level for several centuries. 


A new paper that uses the

temperature record from Byrd Station, a scientific outpost in the center of the West Antarctic Ice Sheet (WAIS),

 says that the western part of the ice sheet is experiencing nearly twice as much warming as previously thought.

The temperature record from Byrd Station shows an increase of 4.3 degrees Fahrenheit in average annual temperature since 1958, three times faster than the average temperature rise around the globe.  If those older temperature readings are accurate, this temperature increase is nearly double what previous examinations have suggested.


 A large problem in making predictions about Antarctic melting is that we currently have insufficient knowledge about the ocean circulation near large glaciers in West Antarctica. This means that researchers cannot predict how water levels will change in the future with any large degree of certainty. 

What is known is that the ice sheet in West Antarctica is melting faster than expected, and new observations published by oceanographers in Nature Geoscience may improve the ability to predict future changes in ice sheet mass. 


Temperature rises are consistent with projections made in the IPCC's fourth assessment report (AR4) but satellite measurements show that sea levels are rising at a rate of 3.2 mm a year compared to the best estimate of 2 mm a year in the report, about 60 percent faster, says a new report. 

They used an analysis of global temperatures and sea-level data over the past two decades, comparing them both to projections made in the IPCC's third and fourth assessment reports. Results were obtained by taking averages from the five available global land and ocean temperature series.


Alaska's Columbia Glacier, an iconic glacier featured in the documentary "Chasing Ice" and one of the fastest moving glaciers in the world, will cease retreating around 2020, according to a study by the University of Colorado Boulder.

Their computer model predicts the retreat of the Columbia Glacier will stop when the glacier reaches a new stable position, about 15 miles upstream from the stable position it occupied prior to the 1980s.   


While New Yorkers (and others on the east US coast) prepare to deal with hurricane Sandy and the possible water surge resulting from the very strong winds and low pressure of the system, a similar situation is expected in Venice on Wednesday; unlike New Yorkers, Venetians are rather accustomed to the phenomenon - familiarly called "acqua alta" (high water) by residents. However, when the level of water is exceptionally high, normal protection systems to shops, offices, and ground floors of homes prove insufficient.

That is probably going to be the case in the evening of October 31st, when the tide is expected to reach to the level of +1.40 meters above average sea level, due to a combination of factors -low pressure, full moon, winds.