November News 2012



People have to adapt and mitigate global warming, expert says

According to JMU Professor Kristen St. John, “I would say it's [polar ice caps melting] definitely cause for concern.  As I understand it, there were not that many unusual changes this year that could account for this extreme change in sea ice.  So while much else was business as usual, why did this happen so, so much?  We’re seeing early clues to problems that really are global scale.  It should be getting our attention.”

Average temperatures in the Arctic region are rising twice as fast as they are elsewhere in the world. Arctic ice is getting thinner, melting and rupturing. The polar ice cap as a whole is shrinking.  Images from NASA satellites show that the area of permanent ice cover is contracting at a rate of 9 percent each decade. If this trend continues, summers in the Arctic could become ice-free by the end of the century.

Kristen St. John

Professor of Paleoceanography and Geoscience Education, James Madison University

stjohnke@jmu.edu

http://www.jmu.edu/geology/people/stjohnke.html

St. John is the author of Reconstructing Earth’s Climate History, which provides context for understanding global climate change today by studying the records of Earth’s past.  She also interacts with the geoscience education community as an associate editor of the Journal of Geoscience Education. In addition to her teacher education charge, Kristen maintains an active research program in marine sedimentology and paleoceanography. Her research primarily focuses on reconstructing Pleistocene ice-rafted debris histories. 

Quotes

“With the ice albedo effect, if we see some external reason for warming to occur, it is because of excess greenhouse gases.  Snow and ice have a very high albedo, it’s very reflective.  If something else is already causing the ice to melt, the excess greenhouse gasses, then, this other step kicks in. We’re shifting the type of surface which means we’re warming that water and absorbing more heat which will cause more ice to melt.  So it starts to accelerate the direction of change that we’re already going in.  It works the other way too.  If climate got colder more ice would form.  That ice has a more reflective surface than the ocean, which means it will make the overlying atmosphere even colder and more ice will form.”

“One perspective on this [extreme change in sea ice level] is that we may have crossed some threshold.  Threshold being that we are shifting into some climate state that is much more sensitive.  We’re talking about an area of the world that is very, very sensitive to climate change.  When we’re talking about global averages in reference to temperature change, the artic is always well above average.”

“It is very, very clear from the geological record that climate has been much more extreme - like 90 percent of Earth’s history was warmer than it is today, which totally seems to go against what they are saying in the news.  And this is not to take away from the fact that Earth is warming and this is a problem, but Earth overall will adapt.  It’s now people that need to figure out how to adapt to a warmer climate - we are causing it.”

“Some of it [reducing greenhouse gases] is a lifestyle change.  If you are really trying to reduce it you have to be less dependent on fossil fuels, less deforestation, and there are so many simple things like carbon calculators.  So, it’s a combination of doing things at an individual level and government regulation.  But also recognizing we need to adapt to some changes - it’s already happening.”

“Sea ice there is not shrinking around Antarctica.  We’ve got some really different things happening. The poles are desert like, it's more dry there than moist.  So desert doesn’t mean hot and cold, it means moisture, dry and moist.  If you shift the participation zone so that Antarctica is receiving more precipitation while it is still cool enough to make snow then it makes sense that it could grow.”

“You are also dealing with an ice sheet there that’s 2 to 3 kilometers thick, compared to sea ice in the Arctic that is 1 to 4 meters thick.  There are borders of magnitude in difference, and you will see a response in that thinner ice much more quickly than you will see in thicker ice.  There’s this delay time, so we wouldn’t expect to see big changes in Antarctica right now.”








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