Fiddling While The Climate Burns

Fiddling While The Climate Burns – Statistical Data Included

Peter Bunyard

PETER BUNYARD EXAMINES THE LATEST EVIDENCE OF CLIMATE CHANGE.

A REPORT FROM the UK Met Office, which largely vindicates what some called an ‘alarmist’ issue of The Ecologist on climate change, warns of severe weather effects to come. But it does not go far enough.

WITH JUST WEEKS to go before the new century, the catastrophic rains that swept as many as 20,000 to their deaths in Venezuela, and the 200km-per-hour winds that battered France could not have done more to bring the message home that nowhere in the world is safe from the impact of climate change. Now, to add weight to what is routinely referred to as ‘anecdotal’ evidence, the UK Meteorological (Met) Office has come out with an updated report: Climate Change and its Impacts: Stabilisation of [CO.sub.2] in the Atmosphere. It is a significant piece of work, but one which has to be read between the lines to get its full import.

We now emit some 7.5 billion tonnes of carbon a year into the atmosphere from the burning of fossil fuels and forest destruction, and emissions have been rising as countries get drawn into the global economy. According to the Met Office’s calculations, we could stabilise carbon dioxide levels 120 years from now if we kept growth in emissions down so that they peaked at 9 billion tonnes per year some 50 years hence and then gradually declined to 2.5 billion tonnes by the year 2250 — at 550 parts per million (ppm) in the atmosphere. The assumption behind this projection is that we will find alternatives to fossil fuels over the new century. A more pessimistic projection is that carbon dioxide emissions will peak at 12.5 billion tonnes per year by 2075 and then decline to about 4 billion tonnes per year by 2250 — at 750 parts per million.

But can we be so sure that a final stabilisation of [CO.sub.2] in the atmosphere at 750 ppm is the worst case scenario? An even starker alternative given in the report is ‘unmitigated’ or ‘business-as-usual’ emissions, in which no steps are taken to limit greenhouse gas emissions (the graphs on the opposite page show these three projections starkly). The current trajectory of greenhouse gas emissions, should they remain unmitigated, will take us to a near fivefold increase in atmospheric carbon one century from now (to 1,300 parts per million compared with the pre-industrial 280 ppm, and more than three times today’s 365 ppm). Indeed, given basic assumptions about global economic aspirations combined with population growth, we could be doubling [CO.sub.2] emissions in the atmosphere every 27 years.

Before we dismiss as ‘unbelievable’ the prospect of such a horrendous increase in greenhouse gas emissions, we should look at the facts. The Italian astrophysicist, Alberto di Fazio, at his Global Dynamics Institute in Rome, has shown from current trends in the growth of [CO.sub.2] emissions that even were we able to substitute natural gas for coal-burning across the globe, and improve efficiencies of energy use by a remarkable ‘close-to-the-limits’ 250 per cent, a century from now we would gain no more than five years’ grace before atmospheric carbon had reached the levels it would do under ‘business-as-usual’. None of that appears in the Met Office’s graphical presentation.

On the contrary, the Met Office leaves the ‘business-as-usual’ trend literally hanging in the air a century from now, so that we are left with the impression that to go along that trajectory is so unlikely (or that its consequences are too terrible to contemplate) that we need spend no more time on it. Instead, the validity of the Met Office’s conclusions as to what we might expect of future climate depends critically on the supposed stabilisation of carbon dioxide levels in the atmosphere over the next few centuries.

Yet from current trends, it looks as if the goal of stabilising atmospheric carbon dioxide at 550 ppm is a non-starter, especially when we consider the long-term marginal effect on emissions of substituting natural gas for coal and dramatically improving efficiencies. Even the 750 ppm scenario would require an aggressive turn-around from current practice, and, with governments still wrangling over the Kyoto Protocol on ‘carbon emissions trading’ and ‘clean development mechanisms’ there is little evidence to date that greenhouse gas emissions are being curbed. The US, if carbon trading is accepted as a legitimate mechanism, will be pushing out 10 per cent more carbon into the atmosphere over the next decade compared with 1990, while China alone will be burning more coal in 10 years’ time than all the OECD countries put together, and that includes the US, Europe, Japan. Add in the remorseless spread of consumerism across the globe and we have a recipe for runaway global warming.

There is more. The unpalatable truth is that we are destroying the world’s forests well ahead of the impact of future climate change. The destruction of tropical forests, in particular through burning, is having a significant effect on the transfer of energy from the tropics to the higher latitudes. The Amazon rainforest is responsible for pumping back into the atmosphere as much as half of the 12 million million tonnes of water that falls as rain. With the forests gone, 20 per cent less water vapour gets back into the atmosphere; a loss in energy terms equivalent to more than 20 times the total energy used by humanity. By destroying the forests we could be throwing a switch on climate which could result in dramatic changes to weather systems, including the unleashing of a spate of powerful El Ninos. None of this prospect is even hinted at by the Met Office.

Andrew White and Melvin Cannell of the Edinburgh-based Institute of Terrestrial Ecology have created a computer model which shows that unmitigated ‘business-as-usual’ emissions will cause a global vegetation ‘dieback’ over 4 million square kilometres — approximately the size of Brazil’s Amazon region and 20 times the size of the UK — within a century. Stabilisation of atmospheric [CO.sub.2] at 750 ppm leads ultimately to vegetation losses of 3 million square kilometres; stabilisation at 550 ppm to losses of one million square kilometres. As vegetation is lost through global warming, so too is the ‘carbon sink’ which currently takes up approximately 25 per cent of human-caused carbon emissions. Since the dieback of vegetation is exacerbated by global warming, which itself results from an ever-greater proportion of [CO.sub.2] remaining behind in the atmosphere, we have here a classic self-accentuating feedback. In essence, the worse the situation, the worse it becomes.

Of prime concern must be the impact of global warming on agriculture. As we would expect, the Met Office models show us that unmitigated carbon emissions seriously threaten agriculture across a broad swathe of the tropics, from South America, across Central Africa to India and South-East Asia. Stabilisation at 550 ppm leads to marginally better results, but the surprise is the conspicuous improvement in tropical yields under conditions which lead to 750 ppm. Yet to suggest an improvement in crop yields of 5 per cent right across South America is surely a nonsense. We know that most of the soils across the 5 million square kilometres of the Brazilian Amazon are washed out and grossly deficient in nutrients for sustaining productive agriculture.

For all such criticisms, the Met Office’s report is a step in the right direction. But we are still left with the suspicion that essential feedbacks — such as the impact of forest destruction on climate — are being left out of the equation. And because the results are so broad-brush in terms of average temperature rises, or changes in precipitation, we have no idea of the potential for damage caused by extreme events, such as the winds that blew over France in late 1999, or the floods that hit Venezuela. It might look on paper as if global warming will give the US and Britain just the right climate for a productive agriculture, but what if the rains fall in the wrong season, or crops get hit by a succession of searing heatwaves just when they are most vulnerable? In the UK, for example, we can expect 10 times more summer heatwaves by the middle of the next century compared with now.

But the key problem is that this report does not give us the sense of urgency that we must do everything in our power now to implement policies and practices that lead overall to the best scenario. It is now eight years since the Framework Climate Convention in Rio. We have little time left, and that means ‘crash’ programmes to improve efficiencies, to get renewable energy sources off the ground, to save and regenerate forests, to curb traffic and change patterns of wasteful consumerism and trade. The warnings are there in valuable scientific studies such as this is, for all its flaws. But still we fiddle on.

Peter Bunyard is co-founder and science editor of The Ecologist.

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