Section: Media Monitor|
8 October 2005
The incredible shrinking ArcticEvery planet, including Earth, features what scientists call an Albedo. The Albedo is the capacity of a planet to reflect light, normally expressed in a percentage. Thus Earth's Albedo is roughly 39% - that is, 39% of the light striking the planet's surface (or cloud cover) is reflected back out into space. Since the amount of light reflected back into space is directly related to the proportion of heat energy lost by the planet, a rising or falling Albedo is an important factor driving global warming or cooling.
In relation to Earth's Albedo, there is a kind of Catastrophe Theory mooted by climatologists called the Albedo effect. The theory goes something like this. If a particularly harsh winter were to set in, and the polar ice caps were to advance, an increased surface area of the planet would become white. Since a white surface is a better reflector of light, the Albedo would be raised. More light would be reflected back into space, and thus more heat energy would be lost. The loss of heat would lower the planet's temperature, which, in turn, would induce more snowfall and thus a further increase in whitened surface area, which raises the Albedo further, and so on. From here, the process continues in a self-perpetuating feedback loop. In short, the theory postulates that if a bad winter ever passed a certain threshold of severity, another ice age would be unstoppable.
A report issued a few weeks ago informed us that the exact opposite effect is in fact taking place. The trouble is, this is not cause for relief but for alarm, for it portends the beginning of a climatological disaster that differs from the above scenario only in that the temperature is at the other extreme. For the Albedo Effect can also work catastrophically in reverse.
In last week's Guardian, George Monbiot reported that in late September the Snow and Ice Data Centre in Colorado released a report demonstrating that the surface area of the Arctic ice sheet is now at its most reduced in recorded history. In the wake of such findings, he surmises that
The Arctic could already have reached tipping point - the moment beyond which the warming becomes irreversible. As ice disappears, the surface of the sea becomes darker, absorbing more heat. Less ice forms, so the sea becomes darker still, and so it goes on.The next week, in the same publication, David Adam unpacked the looming disaster in more detail. Not only is last month's reduction of the polar ice mass the worst in recorded history (an extra 1.3 million square km was wiped out, 20% more than average), but it's merely a feature of an ice recession that is accellerating, and consistently.
Experts at the US National Snow and Ice Data Centre in Colorado fear the region is locked into a destructive cycle, with warmer air melting more ice, which in turn warms the air further. ...In the late sixteenth and early seventeenth centuries, English and Dutch explorers attempted to trace a 'north-east passage' to the Orient by sailing from northern Europe over Siberia. All attempts failed because they ran into an ice pack at the mouth of the Ob river which literally blocked their progress. Today, that passage of Arctic waters is ice-free for two months of the year. Similar changes have taken place in that part of the Arctic overhanging North America. It has been reported, for example, that the Danish navy has begun patrolling the Greenland Coast, marking its territory in the 'increasingly ice-free Northwest Passage' in anticipation of Canadian or US designs on the region. The deliquesence of Greenland's ice mass is a particularly disturbing development, since it threatens the stability of the Gulf Stream. As explained by Martin Rees:
The Gulf Stream is part of a so-called "conveyor-belt" flow pattern whereby warm water flows north-eastward towards Europe at the surface and returns, having cooled, at greater depths. The melting of Greenland's ice would release a huge volume of fresh water, which would mix with the salt water, diluting it and rendering it so bouyant that it would not sink even after it had cooled. This injection of fresh water could thereby quench the "thermohaline" circulation pattern (controlled by the ocean's salinity and temperature) that is crucial for maintaining the temperate climate of northern Europe. If the Gulf Stream were truncated or reversed, Britain and neighbouring countries could be plunged into near-arctic winters, like those that currently prevail in similar latitudes in Canada and Siberia.There is not a soul in the Western world unaware of the issue of climate change and what it portends even for the medium term. But knowledge is not the same thing as action. Needless to say, it will take more than airhead blockbuster movies from Roland Emmerich before we begin to make serious progress in motivating the world to prevent catastrophic climate change. A Waterworld scenario? On the basis of last month's evidence, don't rule it out.
I don't wish to dishearten further, but since writing this article, it has transpired that CryoSat, the very satellite that was intended to monitor the melting Arctic icecap, crashed into the ocean shortly after launch on 8 October. The second stage of the rocket it was launched on failed to decouple, and the entire apparatus crashed to Earth before entering orbit. The satellite cost UK£100m to construct and no backup model was built. The project took British scientists six years to construct.