Wednesday, December 9, 2009

Two climate perpectives: Antarctic sea level rise vs the Maldives

Two recent articles and reports highlight the difficulty in forecasting impacts of a warming climate and the political response. As we've learned from the recent email 'scandal' from the University of East Anglia, the development and presentation of science and its interpretation into a policy context are two very different and complex issues. While the development of international peer reviewed science clearly points to human influence in driving climate change, the complexity of the system under study and the resultant uncertainties make simple messages or calls to action difficult to implement. This is magnified by the scale of the task at hand (ie. changing global patterns of consumption and behaviour) and the politics involved (domestic and geopolitical). While the science still has many questions to answer, particularly in finer scale forecasts of impacts, the political process is one that is - excuse the pun - heating up. Its a difficult but necessary process. In this context climate change has moved out of the realm of scientific debate and into to the realm of social discourse, and this in itself should be seen as a measure of the success of many scientists in bringing the issue to our attention. The science should and will, continue to ask and address the many questions that are raised about climate dynamics and impacts - as any scientific process should - but the key issue at hand is what form of action should domestic and international communities take. In terms of risk the evidence is there, but in terms of action, we have a long way to go and many perspectives to accommodate.

No wonder the task at Copenhagen is difficult.

Antarctic melting

Recently, the Scientific Committee on Antarctic Research (SCAR) reported that sea levels are likely to rise by about 1.4m (4ft 6in) globally by 2100 as polar ice melts, according to a major review of climate change in Antarctica.

The report - Antarctic Climate Change and the Environment - was written using contributions from 100 leading scientists in various disciplines, and reviewed by a further 200. SCAR's executive director Dr Colin Summerhayes highlights "The temperature of the air is increasing, the temperature of the ocean is increasing, sea levels are rising - and the Sun appears to have very little influence on what we see," he said.

Two years ago, the Intergovernmental Panel on Climate Change (IPCC) projected that the global average sea level would probably rise by 28-43 cm (11-16in) by the end of the century.But it acknowledged this figure was almost certainly too low, because it was impossible to model "ice dynamics". Lead editor John Turner from the British Antarctic Survey (BAS) suggested that observations on the ground had changed that picture, especially in parts of the West Antarctic ice sheet.

Warmer water is getting under the edges of the West Antarctic ice sheet and accelerating the flow of ice into the ocean. The Antarctic Peninsula has warmed by about 3C over the last 50 years, the fastest rise seen anywhere in the southern hemisphere, according to the report. But the rest of the continent has remained largely immune from the global trend of rising temperatures.Indeed, the continent's largest portion, East Antarctica, appears to have cooled, bringing a 10% increase in the sea ice extent since 1980.


A letter to the President of the Maldives - from the Spectator

Dear Mr President,

You are obviously very concerned about the effect that sea level rises may have on the Maldives. Your Cabinet has been photographed meeting underwater, and you have even declared that ‘we are going to die’ if the climate change summit in Copenhagen fails. I am now writing with what I hope will be some good news. The scientific side of the situation is quite different to that which you imagine. You are, in fact, not going to die.

Before I continue, I should perhaps state my credentials. I have been a sea-level specialist for 40 years. I launched most of its new theories in the 1970s, 1980s and 1990s. I solved the problem of the gravitational potential surface, the theory that it changes with time; the rotation of the earth, how it affected the redistribution of the oceans’ masses — and so on. Last year, I was awarded a prize from Algarve university for my ‘irreverence and contribution to our understanding of sea level change’.

We both know that the 1,200 islands of the Maldives are all low-lying with the highest point only some 2.5m (8ft) above sea level. Hence, your nation is vulnerable to extreme storms, tsunamis — and, of course, any possible sea level rise.

The IPCC vision is a rise that by the year 2100 may amount to between 30cm and 50cm. This is based on model calculations. Our figure is a 5cm rise, plus or minus 15cm. In a newspaper article, you have suggested that sea levels may rise by between one and eight metres. Those figures, however, do not concur with the physics and known rates of ice melting. So those figures must be dismissed as impossible.

I have been on no fewer than six different field expeditions to the Maldives. We worked in the lagoon, we drilled in the sea, we drilled in lakes, we looked at the shore morphology — many different environments. We have always found the same thing: a total stability for the last 30 years, preceded by a 20cm drop in sea level in the 1970s. We have presented a detailed documentation of the sea level changes in the Maldives over the past 4,000 years. The record of the last 500 years may be of special interest to the situation of your islanders. It shows:

The people of the Maldives had no problems surviving the 17th century, which was 50cm higher than now. Nor the last century, where it rose by 20cm. This bodes well for their prospects of surviving the next change.

I recently visited Bangladesh, a country cursed by floods. In the Sundarban delta, I documented very strong coastal erosion despite zero changes in sea level. So, even here, there is no global sea level rise going on today — just as in the Maldives, in Tuvalu and in Vanuatu, to mention a few famous sites claimed already to be in the process of becoming flooded.

By the end of this century, sea level may have risen by between 30cm and 50cm according to the various IPCC scenarios. Our records suggest a maximum of 20cm. Neither of those levels would pose any real problem — simply a return to the situation in the 17th and the 19th to early 20th centuries, respectively.

So why the scare-mongering? Could it be because there is money involved? If you inhabit a tiny island and can convince the world that its very existence is under threat because of the polluting policies of the West, the industrialised nations will certainly respond. The money is likely to flow in more quickly than the ocean will rise.

This is the fourth time I have written to you. Unfortunately, I think there is a problem with your email service because so far I have not received an acknowledgement. For this reason, I have decided to write this open letter in the pages of The Spectator.

Nils-Axel Mörner

Note from Susainable Seas Editor: What about storm surges and cyclones?

No comments:

Post a Comment