ICE Satellite Maps Profound Polar Thinning 245
xp65 writes "Researchers have used NASA's Ice, Cloud and Land Elevation Satellite to compose the most comprehensive picture of changing glaciers along the coast of the Greenland and Antarctic ice sheets. The new elevation maps show that all latitudes of the Greenland ice sheet are affected by dynamic thinning — the loss of ice due to accelerated ice flow to the ocean. The maps also show surprising, extensive thinning in Antarctica, affecting the ice sheet far inland. The study, led by Hamish Pritchard of the British Antarctic Survey in Cambridge, England, was published September 24 in Nature."
Re:Good-bye ice, it was nice knowing you. (Score:4, Informative)
That would be sensationalism. So far, it is measured in cm; by the turn of the century (90 years from now) it is projected to be a few meters,
Re:Do they know if this is unusual? (Score:2, Informative)
FTFA:
Which... is sort of what healthy glaciers do. Thick, healthy glaciers flow quickly due to the pressure they exert on the deeper portions, giving the lower ice under pressure more plasticity. This could be construed as abnormally healthy glacial activity, but IANAAG (i am not an artic geologist).
I should note my liberal bias, democratic registration, and belief in global warming, else I get modded as a troll or flamebait (it happens a lot if I don't specify my political leanings, sadly, note my posting history...).
Re:Do they know if this is unusual? (Score:4, Informative)
Re:Does it? (Score:3, Informative)
Re:What is the net effect? (Score:5, Informative)
The last article I read in Science [pik-potsdam.de] compared model prediction of sea level rise, and found that observations showed the sea levels rising even faster than the models predicted. Perhaps this was just short-term weather, though: more recent measurements may indicate agreement with the models.
Re:National Post rebuttal (Score:2, Informative)
Re:Don't matter... (Score:4, Informative)
Okay, yes. Technically I agree. The political/economic ramifications of our response to climate change aren't completely within the domain of physical science, so they're not facts in the way that the anthropogenic origin of abrupt climate change is a fact. For example, our technology could suddenly jump forward very quickly, rendering adaptation very simple and cheap.
But we're talking about the future of the human race here. Let's choose the safest option, and try to avoid the worst effects by moving from coal power to modern nuclear power. As technology advances, solar, wind, tidal and geothermal power can play an increasing role. We've stagnated and become complacent in a world powered by cheap oil; another industrial revolution is long overdue.
Re:Do they know if this is unusual? (Score:3, Informative)
Double check your terminology there. The article specifically states glacier flow, not glacier melt in Antarctica. Glacier flow only occurs when you have lots of extra ice pushing more ice down the slope. Flow != Melt! It's way, way too cold in Antarctica for glaciers to melt anywhere on the actual landmass. Thinning ice shelf in this case is specifically due to improved glacial flow, pushing more ice out to where it can melt - in the sea.
Re:Don't matter... (Score:3, Informative)
When I said "moderately stable equilibrium" I was talking about the amount of energy that entered out atmosphere. This was not very clear in my post, and I apologize for that.
Yes, over very large periods of time, the amount of energy that has then been radiated away from our atmosphere has varied as glaciation will increase the bleed off by reflecting this.
But, when we then start to burn off fuels that are the accumulation of energy over hundreds of thousands if not millions of years inside a span that is a few hundred years, that will have an effect. What that effect will be in the long is very difficult to determine.
Maybe the increase in energy will merely result in a slightly higher average temperature resulting in slightly higher water levels and then that becomes the basis for a new equilibrium.
Maybe the increase in temperature will result in more clouds which in turn will reflect more sunshine away and dropping the temperature resulting in larger temperature fluctuations over a span of multiple years like a sinusoid with an average temperature of what we have now just with a larger amplitude.
Maybe it'll run amok from a human perspective, raising average global temperatures 10 C, raise the sea levels 3 meters (10 feet) and make Scandinavia a lush tropical jungle. Hell, I live in mid-Sweden, 120 meters above sea level - what the fuck do I care if Los Angeles, New York, London, Paris, Hamburg, Tokyo and probably a billion people end up drowning or having to move somewhere else? And since it won't happen in my lifetime and I don't have kids, I really don't have a reason to care.
Maybe it'll go the other way. Ten thousand years ago the sea levels were 40 meters (120 feet) below what they are today. That kind of change would also result in some very serious geo-political tensions, as nations that were previously separated by hundreds of miles of sea would now have a land-bridge between them. Not to mention the consequences for fishing. To give you an idea what that might look like, I encourage you to read about The Aral Sea [wikipedia.org]. Or look at Venice. That wasn't a city that was built in the middle of a lagoon. Nor was it something that happened at the pace we're facing here.
Granted, those are the extremes, but increasing or decreasing the sea levels by a meter is going to have some serious consequences we aren't prepared for. They will happen on their own over time, but then we're talking about geological time periods of thousands of years, not the span of a few decades or a single century.
I honestly believe that from where we're sitting, we're on the cab of a run away freight train. We don't have a chance of stopping it before something "bad" happens (compared to the status quo), but we can at the very least lift the foot of the accelerator. Getting there sooner is not always a good thing.
Re:Don't matter... (Score:4, Informative)
Yes, 2008 and 2009 had smaller ice extent minima [uaf.edu] than 2007. But the point is that climate models had previously predicted [demon.co.uk] larger ice extent minima than were observed in 2007. So the last several years tend to confirm that the previous measurements were due to short-term weather variability rather than a flaw in the climate models.
Ask, and you shall receive [uiuc.edu]. No serious scientist is actually "guessing" that the decline has been constant, and no climate model that I'm aware of makes that prediction. Short term variability is expected, but the data shows a clear downward trend over the last 30 years.
Re:Do they know if this is unusual? (Score:5, Informative)
I've discussed [dumbscientist.com] this claim before. Short version: there hasn't been a cooling trend over the last ten years, major or minor.
The climate varies naturally on long timescales but Meehl 2004 [ucar.edu] shows the current warming can't be accounted for by natural forcings. Greenhouse gas emissions are the only way we can explain the temperatures over the last ~40 years.
Re:Good-bye ice, it was nice knowing you. (Score:3, Informative)
Re:What is the net effect? (Score:4, Informative)
Re:What is the net effect? (Score:5, Informative)
They have never been able to accurately predict what the weather will be tomorrow. It is arrogant for Al Gore (who incidentally also invented the Internet) to claim he knows what the effect will be decades from now. The largest cause of CO2 emissions is natural activity. The most abundant greenhouse gas is water vapor. http://en.wikipedia.org/wiki/Greenhouse_gas#Greenhouse_effects_in_Earth.27s_atmosphere [wikipedia.org]
3 myths in one go? Not bad. First link on google for climate myths gives 3 rebuttals: Chaotic systems are not predictable [newscientist.com], CO2 isn't the most important greenhouse gas [newscientist.com] and finally CO2 isn't the most important greenhouse gas [newscientist.com]
Re:Do they know if this is unusual? (Score:3, Informative)
(And that's a big assumption given the major cooling trend we have been in for the last 10 years.)
Oh please. Take a look at the graph [www.dmi.dk] and tell me what cooling trend you see? I know that 1998 was exceptionally warm, but one years does not make a trend.
Re:Don't matter... (Score:3, Informative)
We have been warned for years on end that coastal inundation would be the direct effect of polar melting.
But inundation should not be a delayed effect. It should appear immediately, and in direct proportion to the melting.
So where is it?
Two South Pacific islands have disappeared beneath the waves, as climate change raises sea levels to new heights. [bbc.co.uk]
Tuvalu, soon to be no more. [earthtimes.org]
World's deltas subsiding, says study. [google.com]
Re:What is the net effect? (Score:4, Informative)
According to a recent survey [people-press.org], about 10% of scientists believe that the current warming is natural, 4% believe there is no warming, and 84% believe the current warming is caused by humans. So, yeah, some scientists are skeptical of global warming.
But stop trying to count heads on each side of the debate. As I've repeatedly stressed in that last link, science isn't democratic. It's about evidence. When I see some convincing evidence against the existence of abrupt climate change, then I'll be interested.
And of course the IPCC doesn't conduct original research. They compile previously peer-reviewed research into reports that summarize the best scientific evidence available.
Re:What is the net effect? (Score:3, Informative)
Or maybe you could re-read my point that the natural carbon cycle is a closed cycle. That means any CO2 emitted by respiration and decomposition was very recently absorbed from the air as the plant grew. So it doesn't change the overall concentration of CO2 in the atmosphere. Another independent line of evidence is that the isotopes in vegetative CO2 don't match the current isotopes of CO2 in the atmosphere. The CO2 in fossil fuels, on the other hand, has been locked underground for millions of years and has the same isotope ratios as the CO2 in the atmosphere.
Make no mistake; the current skyrocketing [www.ipcc.ch] CO2 concentration is due to human emissions.
Re:What is the net effect? (Score:3, Informative)
You're absolutely right that peer-reviewed journal articles are far superior to pop science sources. But the New Scientist articles he quoted accurately reflect the science in those peer-reviewed journals, which I've linked [dumbscientist.com] extensively so you can compare.
Huh? What in the full paper [pik-potsdam.de] led you to that bizarre conclusion?
Re:What is the net effect? (Score:3, Informative)
Oh, the global cooling myth, how quaint! Haven't heard that one for a while. I see you have gotten the one where decades and 100 of decades are mixed up. The trick is to count the zeros! ;)
Seriously, how can anyone be surprised that the outlook 10000 years ahead is different from 100?
There is also a different global cool myth, which claims that the scientist agreed that such was in store for us around 1970. Hope I didn't steal your thunder ;)
Re:"man made" (Score:4, Informative)