Wake up and smell the climate change

THE OBSERVER , LONDON
Robin Mckie
Jun 17, 2006



Strange days have reached Ny-Alesund, Europe's most northerly research station. Perched at the very edge of the continent, in Svalbard, Norway, a mere 1,000km from the North Pole, the center's international scientists have been experiencing weather that is becoming increasingly unpredictable.

The archipelago was balmy and calm at the end of April, when it should should still have been gripped by ice and screaming winds. In May, Vigdis Tverberg of the Norwegian Polar Institute, reported that waters in the Kongsfjorden -- the long strip of water that pokes eastwards into mainland Svalbard at Ny-Alesund -- were now 2oC warmer than they used to be a few years ago.

Two degrees may seem a modest rise, but the effects are profound, as Tverberg stressed: "Normally, the temperature in the fjord would be close to freezing. This winter the cooling of the water has probably never been close enough to produce an ice cover."

Thus a major strip of water, on a latitude parallel to the northernmost tip of Greenland, failed to produce a covering of ice this year. The inference is clear, say researchers. Global warming, driven by increasing levels of carbon dioxide in the atmosphere, is not only increasing air temperatures, it is causing the oceans to warm alarmingly.

Neither is Kongsfjorden unique. According to Tverberg's colleague, Sebastian Gerland, all the other fjords on this normally ice-locked coastline have remained open, thanks to the startling warming of their waters. Polar ice is not so much dwindling, as scientists once suggested might happen, it is disappearing before our eyes.

The implications are deeply worrying, as Graham Shimmield, director of the Dunstaffnage Marine laboratory, in Scotland, points out. His researchers have just finished a survey of Kongsfjorden in a bid to find out the effects of climate change on its marine life.

"There is a very carefully delineated food chain in the Arctic," he said. "Plankton are eaten by fish, which are eaten by seals, which are eaten by polar bears. It has been a very stable supply for a long time. Now the whole chain is changing and we have no idea what the consequences will be. For the polar bear, which is already suffering because it has less pack ice to hunt on, the problem is particularly worrying."

The likely impact on wildlife is clearly disturbing. But the issues go far beyond concerns for polar creatures. They sound an alarm bell for the entire planet.

For years, scientists have stressed the Arctic and the Antarctic are the most climatically sensitive parts of our planet. Global warming was always going to hit the poles with disproportionate severity, they said. Now those predictions are being proved correct, not just in the warming polar waters.

In the case of Greenland, scientists at NASA and the University of Kansas reported this year that previous estimates of the rate of melting of Greenland's glaciers had been too low and too optimistic in assuming it would take centuries to heat and melt its massive ice shield.

Instead, when NASA's Eric Rignot, and Pannir Kanagaratnam, of Kansas University, studied Greenland's glaciers, they uncovered an unexpected effect. As air temperatures have risen -- roughly 3oC in the Arctic over the past two decades -- the resulting meltwater has poured to the bases of glaciers and acted as a lubricant. Thus the marches to the sea of these great rivers of ice are being accelerated, raising the amount of ice dumped in the Atlantic each year from 100km3 in 1996 to 220km3 last year.

Neither is the Antarctic exempt. In March, scientists from the University of Colorado at Boulder, using satellites to monitor tiny fluctuations in Earth's gravity, concluded that the continent is now losing similar amounts of ice, about 150km3 a year.

This will have several profound consequences, say scientists. First, it will help to increase the rate at which sea levels are now rising. At present, the figure is about 2mm a year, but it is destined to increase considerably over the coming decades. For countries such as Holland, a quarter of which currently lies below sea level for low-lying Bangladesh and for coral island nations such as the Maldives, Tuvalu, and Vanuatu, it is a deeply worrying prospect, particularly as climatologists also predict increased numbers of major storms as another consequence of global warming.

All these places will become increasingly vulnerable to massive sea surges sweeping over their strained ocean defenses. Already the world's coral reefs and islands are suffering: swamped by rising waters, battered by storms and bleached by seas becoming increasingly acidic from the carbon dioxide they are absorbing.

It is a grim prospect. Yet there may be even more worrying, more serious effects triggered by the disappearance of the polar ice caps.

Those vast sheets of bright, white ice make near-perfect mirrors that shine back 80 percent of the sunlight that falls on them. Thus they help to keep our planet cool. This measure of reflectivity is known as "albedo" (from the Latin word for whiteness). A perfect reflector would have an albedo of 1.0; the albedo for polar ice is around 0.8.

By contrast, the albedo for sea water is around 0.07.

The difference between these two figures is stark. Ice has one of the highest albedos of any substance on Earth, sea water has one of the lowest, so we are replacing our planet's best reflector with one of the worst. In this way, more and more solar energy is being absorbed as ice cover is lost, causing the oceans to heat up even more -- which, of course, will trigger even further losses of ice.

Thus a nudge provided by modestly increased carbon dioxide levels is amplified into a major change.

The bad news doesn't stop here, however. There is the issue of the melting of the planet's permafrost, the thick layer of frozen soil covering much of the ground in the high latitudes of the northern hemisphere.

The trouble, as Elizabeth Kolbert points out in her newly published analysis of Earth's woes, Field Notes from a Catastrophe, is that the permafrost acts as a repository for greenhouse gases. One estimate suggests there are 450 billion tonnes of the stuff locked up in the world's perm-afrost. "As the climate warms, there is a good chance that these gases will be released into the atmosphere, further contributing to global warming," she says.

These two effects, loss of albedo, and the release of permafrost gases, are known as tipping points. Once passed, reversal becomes nigh impossible. As Kolbert says, the climate is like a rowing boat.

You can tip it and it will return to an even keel. You can tip it again, and once more it will return to its original state. But if you tip just a little too far, it will capsize.

That is the danger Earth now faces: the overturning of our climate system, from its relatively stable, moderate status to one in which we have recreated the climate of the Cretaceous era, when there were crocodiles at the poles and the planet cooked.

The question is: how did the planet reach its current status? More importantly, what can be done to halt our seemingly relentless passage towards the Cretaceous? The answer to the first question is, of course, the easier. It can be traced to the moment, in 1765, when James Watt -- wandering across Glasgow Green -- conceived of the idea of a separate condenser for the steam engine. Patented in 1769, his invention made steam power feasible and economic. It unleashed the Industrial Age the burning of Earth's fossil reserves of coal, oil and gas and the injecting of much carbon dioxide into the atmosphere.

In those days, there were approximately 280 parts per million of carbon dioxide in the atmosphere. That level has inexorably increased, indeed it has accelerated, until today, when there are about 380. And most scientists do not envisage this rise flattening out until it reaches 500 to 550 parts per million, a prospect that has deeply unsettling implications. Carbon dioxide -- like all other greenhouse gases -- absorbs the solar energy that perpetually beats down on our world, holds it, then radiates some back to Earth. The effect is to heat up the atmosphere.

This is not necessarily a bad thing. If there were no greenhouse gases, our world would be a decidedly chilly one, as the pion-eering British physicist John Tyndall realized almost 150 years ago. Were it not for heat-trapping gases such as carbon dioxide, solar radiation would be reflected straight back into space.

"The warmth of our fields and gardens would pour itself unrequited into space," he wrote. "The sun would rise upon an island held fast in the iron grip of frost."

On the other hand, if you get too much of the stuff, problems arise, as is revealed through the example of our sister planet Venus.

Although its orbit is relatively close to Earth's, and its size is almost identical, conditions there are as near to hell as you could envisage because its atmosphere is mostly carbon dioxide. The greenhouse effect there generates surface temperatures of 450oC, hot enough to melt lead.

No scientist is predicting such a fate for the Earth, of course. Nevertheless, our world cannot avoid disruption even if it could limit global warming to an increase of only a few degrees. The issue is: how can we mitigate the changes we have unleashed? More importantly, have we the political will to carry out the industrial makeover needed to flatten out that curve of rising carbon emissions before our viability as a species is threatened?

There are many eminent scientists and experts who remain optimistic. Equally, there are those who feel the prospects for our planet are hopeless. Both are united on one issue, however: no matter how bleak our position, there can be no excuse for inaction.

It is a point stressed by the US anthropologist Jared Diamond. In his recent book Collapse: How Societies Choose to Fail or Succeed he outlines examples of societies -- such as the Vikings in Greenland -- who refused to changes their ways and perished as climate change swept their Arctic colonies. By contrast, there is the example of the people of Tikopia, in the Pacific, who when faced with environmental devastation caused by pigs, their favorite source of protein, that were rooting up and destroying their farmlands, acted with commendable decisiveness. They slaughtered every pig on the island.

Our prospects and our choices may not be quite as stark as that -- at least not yet. On the contrary we have many courses of action. We are still in control of our own fate.

As Diamond stresses: "Because we are the cause of our environmental problems, we are the ones in control of them, and we can choose or not choose to stop causing and start solving them. We don't need new technologies to solve our problems while new technologies can make some contribution, for the most part we just need the political will to apply solutions already available. Of course, that's a big `just.' But many societies did find the necessary political will in the past."