Worry.....
A few weeks ago, in a posting on sea level rise, Eli pointed out that sea level rise lags warming by a considerable extent. This accounts for a 500 year delay between when you stop emitting CO2 and the final sea level.
(click to enlarge)
To repeat the top figure is the prediction for increasing CO2 by 1% a year for 70 years and then holding it constant, the bottom is for increasing CO2 by 1% a year for 140 years and then holding it constant. But, as was pointed out, there is a caveat to this prediction, that glaciers respond slowly to external forcings.
A recent feature article in The Earth Observer, v. 18(3), p. 8, 2006 casts strong doubt on that article of fate. The authors, Leigh Stearns and Gordon Hamilton report on measurements by others on two glaciers in southeast Greenland, Kangerdlugssuaq and Helheim. The flow has speeded up greatly, the calving front has rapidly retreated, and the ice surfaces are 100 m lower.
The 11-14 km/yr flow speed cannot be accounted for by internal pressure on the ice and the associated deformation.
The scientists speculate that warmer summer temperatures observed in this part of Greenland are melting increasing amounts of water that is subsequently stored in surface ponds. This melt water eventually reaches the glacier bed, lubricating the ice-rock interface, leading to acceleration. Kangerdlugssuaq and Helheim glaciers are not the only glaciers in Greenland known to be undergoing recent rapid changes. Jakobshavn Isbræ, a tidewater glacier at a comparable latitude (69º N) in west Greenland accelerated 30% between 2000 and 2003 [Joughin et al., 2004] and retreated more than 3 km over the same period [Thomas et al., 2003]. The picture emerging from these observations is one in which large changes in ice dynamics can occur on short timescales of a few years. If the mechanism triggering the changes of Kangerdlugssuaq, Helheim and Jakobshavn affects other Greenland outlet glaciers, which currently show stable ice dynamics [Stearns et al., 2005], the mass balance of the ice sheet will become increasingly negative, unless balanced by an equal increase in snow accumulation, and rates of sea-level rise will increase much faster than current models predict.Oh well.
Update: If you have not already read Jim Hansen's article in the New York Review of Books do so. The base of his argument is the catastropic scenerio discussed in this posting.
Update II: The LA Times publishes a front page article on Greenland glaciers in a perfect storm of articles in the yellow press. And, for the calmer heads we have an earlier post from Real Climate. ThLA Times article was picked up by Political Animal, and other blogs (follow the trackback)
Update III: And to close the circle, Real Climate answers Eli's request for more within the hour. Good going guys:)
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1 comment:
Hi Eli, I return to the analogy of lungs (planet & human). A smoker may continue all his life with no apparent or observable harm other than the visible ageing of skin, and staining of teeth. But doctors and radiologists know the physical realities of cardio thoraxic and respiratory diseases.
The fact that one man may smoke 60 a day with no apparent hindrance, just means he has not tried to play soccer or run a marathon lately. The evidence is there: physical, chemical and biological, of theaccumulation of nicotines and tar in the lungs. By enlarge the individual will be unaffected in his daily life, but he would not ultimately be defined as a fit or healthy individual.
And if he does not give up or moderate consumption, tobacco and smoke inhaled will 'reduce' his lifespan. As a smoker my usual reply to this 'reality' is well we all have to die of something. But it would not occur to me to suggest that smoking is fine or encourageable, which incidentally is what the tobacco industry still does, because it is profitable. The final and cynics irony being, well that way we have to pay less pension for less people for less time.
The same analogy applies to the planet or 'earth' Because nature appears to recycle our CO2 and because we are not plagued by smog as London and other cities were plagued during the industrial revolution, and because we overcame the dirty industry era, all appears fine on the surface.
The reality of course is different even at ground level, take Athens, Shanghai or any other densely populated with high pollution levels evident in the air. Most nations still have one or two major cities in these conditions with increases in respiratory diseases. But with the onset and growth of modern medicine and surgery, people live under the illusion of indestructibility, of course ignoring the fact people die in hospitals (or at home) everyday from made made diseases.
So can nature, the atmosphere and rain forests continue to soak up any excess CO2. Do vested interests and the Oil industry like the tobacco industry carry on fooling people that everything is fine. Keep smiling! profits are up so everything must be ok. hmmmm.
No imminent glazier or icecap melt, and floods, no imminent global warming, no imminent worries and man's innate faith in technology, yeah well tell the dead or the dying about it.
Tell me, if people did not protest at logging of the Amazon, would we even have what's left of the Amazon forest. The Rain forests are the lungs of the planet. Can forests in Scandinavia & Canada replace them, hmmm does climate and temperature not affect where CO2 accumulates?
But I guess in the end, it will take a man made disaster for people to listen. But by the time a patient is aware he has respiratory problems the damage is done, and the damage is irreversible.
If you overfish & do not protect breeding stocks, you have no fish tomorrow.
If you overpollute and do not moderate CO2 emissions and greenhouse gases, you have consequences. That is not only logical, but factual and hence scientific even if not 99.97 per cent accurate or verifiable proof.
So is the universe 14 billion or 17.3 billion years old, both answers cannot be 99.97% accurate factual or verifiable proof. Supposing either answer is/was in the first place. But pollution today is, and can be counted in gallons, barrels of oil, tonnes of coal, cubic metres of gas, and tonnes or cubic metres of CO2. Even the Oil industry would be fools to deny or argue the facts. All they can argue is the verifiability or not of the effects on our atmosphere and climate. Q
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