Robin Bell is a senior scientist at Columbia’s Lamont-Doherty Earth Observatory. She’s led seven expeditions in Antarctica to study how our warming climate is changing polar ice sheets.
Robin Bell: To understand any process, you have to understand it from start to end. And what we want to be able to do with ice sheets is actually model how they grow and how they collapse.
She said three big changes have become evident in the last five years.
Robin Bell: We’re seeing the edges of ice sheets drop down. At the same time, they’re flowing towards the oceans faster. And the third signal, is one we’ve measured from space, is they’re actually weighing less.
Bell said it’s more difficult to figure out what’s actually going on inside the ice.
Robin Bell: That’s what matters a lot. It’s kind of like whether the floor is slippery or not. You have to image through all that ice sheet to be able to see what’s going on at the bottom. That’s the challenge that we’re still after, is understanding the physics at the bottom of ice sheet.
She said understanding the physics of ice sheets will help scientists predict how much ice will melt into the ocean as global temperature increases, and how sea level will rise.
Robin Bell: This is likely to be a period of increasingly rapid rising sea level, and we need to know how we need to change around the edges of our world.
Dr. Bell expanded on the three big changes scientists are seeing in the polar ice sheets.
Robin Bell: The changes that have occurred in the polar regions in the past few years have been remarkable. Mostly, we’ve seen them from satellites. We’re seeing the edges of ice sheets drop down, so they’re sort of getting lower. At the same time, we’ve measured that they’re speeding up, so they’re flowing towards the oceans faster. And the third signal, is one we’ve measured from space, is they’re actually weighing less.
She said that before scientists began a concentrated effort to study the poles, no one knew much about how ice sheets function.
Robin Bell: Our understanding of how ice sheets change is improving. But the problem is, some of the critical processes are hard to see. We have hard time seeing what’s going on in the bottom of the ice sheet. That’s what matters a lot. It’s kind of like whether the floor is slippery or not. You have to Image through all that ice sheet to be able to see what’s going on at the bottom. That’s the challenge that we’re still after, is understanding the physics at the bottom of ice sheet. Bell’s current research project, called Operation ICE Bridge, will fly over the edges of ice sheets. Instruments strapped to the belly of the plane will measure how thick the ice is, and where the rock lies underneath.
It is a scientific fact(law)that ice cannot melt when the temp is below 32 so someother process is at work. Resonance frequencies can break up ice. After all it brought down the Tacoma-Narrors bridge. Sublimination of ice cannot be ruled out.
I think the pressing thing confronting us is how to tackle with it efficiently, after admitting this fact.
If the ice sheets are flowing into the oceans faster, they are growing, not shrinking. In fact, we know that ice is building in Antarctica. Also, I am of the understanding that the average temp down there is around -40. A 3 degree rise in global temps will not cause any melting. If the north pole melts, there will be zero rise in sea levels as the ice is already in the water.
Since we have less than one hundred years of data, we know almost nothing about what long term averages are. This is bogus “science” being used to frighten people. And nature doesn’t care. the earth has been cooling since 1998. How much cooler will it get? How long will the cooling last? How will agriculture in the higher latitudes fare in this time of cooling? Remember, the little ice age was literally a killer of humankind.
Thank you for your sensible comment. When I read articles like that I always wonder whether the satellite photos they claim showing “shrinking” ice are taken at the same time of year. If one studied photos from July and again from January the amount of ice would be significantly different. The Antarctic Circumpolar Current is fed by the Atlantic, Pacific and Indian oceans and may be receiving warmer water than in the recent past…maybe. The Antarctic bottom water is formed from seawater that cools and drops so it is not warmer than before. Here is a link to the 1975 “scientific” Newsweek article claiming a global freeze in the near future http://www.denisdutton.com/cooling_world.htm. We now know what baloney that prediction was.
There are many well-meaning comments on this post but some are misleading.
AP and Ben, air temperatures in the Antarctic summer – along the coasts – can and do swing up high enough high enough to melt ice. The ice in Antarctica flows outward toward the coasts, and warmer temps at the coasts would affect that flow. That’s partly what Robin Bell and other scientists are trying to measure – the flow of ice streams toward the ocean surrounding Antarctica. You can’t just consider air temps, by the way. The temperature of that surrounding ocean itself also plays a role in melting ice. Ben, I’ve asked you several times but still have not seen your evidence for global cooling. I ask again: what is your evidence?
Bill, the photos I’ve seen of the changing size of polar ice sheets are from the Arctic, not Antarctic, and yes they are taken at the same time of year. Arctic ice behaves very differently from Antarctic ice because it is just frozen ocean – while Antarctica is an actual land continent.
Mainly what strikes me here is your lack of trust for scientific expertise. These scientists are studying these complex systems – trying to understand them. They have prepared all their lives to be able to conduct these studies. But you know better than them? I admit … it baffles me.
Best,
Deborah
Two heads are better than one.
Portuguese Proverb~ A rich widow weeps with one eye and signals with the other.
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