According to ever more extreme forecasts, temperatures may rise by up to five, eight, eleven… degrees Celsius over the next hundred years, disrupting agriculture, plant and animal life and our vacation plans. In Britain, we don’t know whether to laugh or cry: ‘The Med may get too hot for holidays’, but, there again, ‘Norfolk to be the new Med’.4 But in already arid regions of the world the effects would be dire. The rising temperatures will melt the polar icecaps, raising sea levels by half a metre, a metre, 7 metres, 70 metres… The heat will push climate systems into overdrive, producing longer, drier droughts, heavier downpours, more sudden floods, more vicious storms… No wonder there’s now a ‘coalition of environment, development, faith-based, women’s and other organisations’ piteously terming itself Stop Climate Chaos.
The cause of all this is believed to be the increasing concentration of greenhouse gases in the atmosphere, most notably carbon dioxide (CO2) produced by humankind’s burning of fossil fuels. Believed, that is, by virtually all scientists – and disbelieved by a small minority who hold either that there is no trend of rising temperatures, or that if there is it is due to terrestrial natural causes or else solar effects.5 However, the balance of likelihoods now leans very strongly towards man-made carbon dioxide, as we shall see.
In a trenchant 1995 sceptics’ handbook, But Is It True?, Aaron Wildavsky quoted a 1981 paper in the journal Science by James Hansen of NASA’s Goddard Institute of Space Studies in New York predicting that ‘potential effects on climate in the twenty-first century include the creation of drought-prone regions in North America and central Asia as part of a shifting of climatic zones, erosion of the West Antarctic ice sheet with a consequent worldwide rise in sea level, and opening of the fabled Northwest Passage’. Hansen added that evidence of warming due specifically to man-made carbon dioxide ‘should emerge from the noise level of natural climate variability by the end of the [twentieth] century’.6 Wildavsky’s purpose in 1995 was to mock the fanciful nature of these visions. Yet in 2007 they are all happening. As late as 2003, the Sunday Telegraph gloated that climatologists’ disastrous predictions for the Arctic icecap were falling ‘foul of reality’: ‘The latest research points to a deepening of the polar freeze,’ the article assured us. Since then, melting has accelerated faster than even many scientists were predicting.
It’s a good instinct to doubt, and a better one to test for yourself. Try checking the temperature records where you live. Check the national records. Or maybe you don’t think that temperatures measured here and there are a reliable indicator of the heat received by the Earth. Then ask gardeners and birdwatchers whether they’ve noticed any changes. Ask alpine ski resort managers how business is. Ask English viticulturists.
Ask yourself about the 2,000 or more scientists who contribute to the United Nations Intergovernmental Panel on Climate Change, the body that makes the most influential predictions in the field. Is it just a ‘quango-cum-travel-agency for those whose salaries depend on keeping the world worried about global warming’, as some columnists think? The vast majority work for universities or national institutions dependent on government funding. Half of them owe their salaries to the American taxpayer. How can the IPCC be a conspiracy when its findings so clearly do not suit the governments that support it? Wouldn’t governments arrange matters so as to hear better news?
From chemical analysis of rock samples and ice cores which contain historically trapped gas, scientists believe that the concentration of carbon dioxide in the Earth’s atmosphere was rather stable at around 280 parts per million (ppm) for more than 20 million years. In 1958, Charles Keeling of the Scripps Institution of Oceanography began taking direct readings at the summit of Mauna Loa in Hawaii, far from any source of pollution. Allowing for the carbon dioxide taken up by oceans and vegetation, each year showed a small, steady rise by an amount corresponding closely with the quantity of carbon-based fuel burned around the globe. When Keeling died in 2005, his employer called his figures ‘the single most important environmental data set taken in the 20th century’.7
Carbon dioxide in the atmosphere was constant until about 1800. The rise began modestly in the nineteenth and early twentieth centuries at a rate of 0.25 ppm a year. When Keeling began his work it stood at 315 ppm. Now the annual rise is at least 1.5 ppm. When the figure was announced for 2006 – 383 ppm – the London Metro, armed with a quote from David King, made a poorly judged attempt to heighten the alarm: ‘CO2 levels “hit 30m year high” ’. But the drama is not in comparison with the state of affairs long before the evolution of the human species, it is in the inexorable increase since the beginnings of industrialization.
None but the most recalcitrant petrolhead would contest these data or the deduction that this carbon dioxide must be man-made. But what about temperatures? The long view was laid out in 1999 by Michael Mann, a statistical climatologist at the University of Virginia. He pooled data gathered by modern instruments with temperatures going back a thousand years ‘reconstructed’ from analyses of tree rings, corals and ice cores. The resulting graph has become known as the hockey stick because of its sharply upturned right-hand end, representing recent rising temperatures after a long period of stability. It drew fire from climate sceptics for its use of proxy data gathered from disparate sources. But in the absence of anything better, it would surely be remiss not to attempt such a study at all – and besides, economists and politicians routinely use this method. Despite criticism, Mann’s graph has been substantially confirmed by more recent studies, and the 2007 report of the IPCC features an improved version of the same basic trend line. This latest report expects temperatures to rise by between 1.0 and 6.3°C by 2100, with around 4°C judged most likely.
The hockey stick graph of actual and predicted rising temperatures and that for the concentration of carbon dioxide in the atmosphere look remarkably similar, strongly suggesting (though not proving) a correlation between the two. However, because the upturns in the two graphs are so recent – seen in only the last few decades over a span of ten centuries – there remain uncertainties about the extent to which temperatures will follow the rising carbon dioxide trend and the time delay in their doing so. These have vital implications, not only for understanding the scale of global warming, but also for deciding how to deal with it.
Climate studies indicate that if carbon dioxide emissions ceased tomorrow it would still be ten to twenty years before the last molecules of the gas were effectively distributed through the atmosphere to exert the maximum greenhouse effect. It would be another thirty to fifty years before the infrared radiation they absorbed was passed on via other constituents of the air to produce heating at the Earth’s surface – although ice core studies of earlier increases in carbon dioxide suggest that the full temperature effect might not be felt for a thousand years.
Add to this uncertain wait the greater uncertainties (but potentially greater risks) associated with what have become known as tipping points – phenomena of positive feedback where an effect produced by warming in turn promotes further, perhaps sudden, warming. The list seems ever-growing: as polar ice melts, reflective snow is replaced by dark sea which absorbs more heat; as peat in the soil warms it releases methane, another greenhouse gas; if plants die from overheating, they cease to absorb carbon dioxide or, worse still, release it if they are consumed in forest fires; and so on. If we pass these points, it is claimed, it will be impossible to reverse the damage no matter what we do.
Let us be more positive.
First of all, will things actually get worse? Newspapers always emphasize the negative, so front-page headlines warning, say, of ‘The century of drought’ are to be expected. Potentially increased crop yields or reduced winter deaths in other parts of the world go unremarked. Nevertheless, there are sound reasons to expect that the human situation will become overall more acute, if not as desperate as the media portrays – reasons such as net loss of stable, temperate climate zones, a more energetic climate system powering extreme w
eather events and, not least, the upheaval of change itself. Smaller environmental changes than those we may be confronting have been sufficient to destroy local civilizations during the past several thousand years of relative climate stability. This time, we face either ‘quick and possibly costly adaptation’ or migration, ‘which has become difficult or, in some cases, impossible in the modern crowded world’.8
Despite this, the Earth as a whole remains highly habitable, much of its surface amply adapted to human life. The parts that are best adapted will doubtless shift a little, but climate change over the next century need not be a catastrophe and could prove no more than a moderate inconvenience for most people. Other parts will become less genial, but it’s not as if this is a novelty. Enough societies struggle to survive today in areas already maladapted to human life, whether due to natural forces or human intervention.
How do we adapt? The odd bedfellows of the Stop Climate Chaos campaign group reflect the uncertainty: do we go back to nature, do we try progress, do we just pray? Climate change is an issue that affects us all, and there is an understandable feeling that we should all contribute towards resolving it. But the present focus of personal effort on using low-energy light bulbs and switching off appliances on ‘standby’ seems woefully at odds with the scale of the problem. It may even be unhelpful. James Hansen has warned that without a government hand on the tiller, ‘conservation of energy by individuals merely reduces the demand for fuel, thus lowering prices and ultimately promoting the wasteful use of energy’.9
We need to think bigger. Faced with a large problem, it sometimes helps to break it into more manageable chunks. In 2004, Stephen Pacala and Robert Socolow, an ecologist and an engineer at Princeton University, looked at the upward graph of carbon dioxide emissions, projected to rise to 14 billion tonnes of carbon burned per year by 2054, and the horizontal line if levels could be held where they are at present, at 7 billion tonnes a year. They divided the fat wedge between the two lines into seven equal thinner wedges, each representing a reduction of 1 billion tonnes a year by 2054. They then identified not seven but fifteen existing technologies that could each account for a wedge of carbon.10 From staring disaster in the face, we were suddenly shown to have the luxury of choice in how to avoid it. The ideas are split between reducing energy demand (halving car miles, doubling car fuel efficiency, improving building insulation, for example), substituting carbon-free energy sources (nuclear, solar, wind), and capturing carbon dioxide (planting trees, sequestering power station emissions). What Pacala’s proposal makes clear in its unideological way is that the solution to the problem is unlikely to be either entirely technological or entirely the self-denying ordinances of the dark green environmentalists. It’s a mnemonic more than a prescription, but it shows that a start can be made.
How much it will cost to make such wholesale changes is anybody’s guess. There will in any case still be an additional cost to adapt to climate change already on the way that mere stabilization of carbon dioxide emissions (as opposed to a cut) does nothing to forestall. And of course, doing nothing also carries an economic cost. However, there is in fact reasonable agreement among estimates of the cost of addressing climate change arrived at by sources ranging from Friends of the Earth to multinational accountancy firms. (There is, as you might expect, greater divergence in estimates of the cost of doing nothing, although this cost is reckoned to be at least as great as, and by some very much more than, the cost of mitigation.)
As climate change becomes a political and economic issue, and as it is increasingly realized that some climate change is inevitable, the phrase ‘dangerous climate change’ has entered the lexicon. But this is a largely meaningless concept. Norfolk’s ‘new Med’ is presumably not ‘dangerous climate change’, but then Norfolk’s new Med may be the Med’s new Sahara. It is not sensible therefore to attempt to put a price on preventing dangerous climate change. However, economists do agree on the cost of limiting the global average temperature increase. Capping the rise at 2°C will come out at between 1 and 2 per cent of global GDP. This puts the price tag in the area of $500 billion to $1 trillion a year, or around a hundred dollars, euros or pounds per person per year – hardly unmanageable, especially if the load is distributed more equitably towards the rich countries responsible for the emissions.
Pigs Might Swim
‘London-on-Sea: the future of a city in decay’ Daily Telegraph
With its white beaches, scattered palm trees and lightly clad inhabitants, the tiny country of Tuvalu in the South Pacific Ocean looks in newspaper photographs like an island paradise. But there is trouble in paradise. The eight little atolls that make up Tuvalu rise only 5 metres above sea level and are in the front line of global climate change. While their politicians tour the world lobbying unsuccessfully for cuts in carbon emissions, Tuvaluans wait nervously for the next high tide that will wash salt water over their crops and round the trotters of their grazing pigs.
‘Sinking islanders are facing mass evacuation’, intoned one recent British newspaper headline, although of course neither the islanders nor their islands are actually sinking. It is the sea that is rising. According to Mark Lynas’s colourful tour d’horizon of parts of the world already feeling the effects of climate change, High Tide, Tuvaluans now face the unenviable choice of whether to move and live ‘cultureless and uprooted in a foreign country, or stay on the land of their forefathers and die’.1
Sea levels have risen by about 20 centimetres over the last century. They are rising on average (the effect is not evenly spread around the world’s oceans) by 2 to 4 millimetres a year at the moment. The 2001 report of the UN’s Intergovernmental Panel on Climate Change (IPCC) predicted that sea levels might rise by 49 centimetres by 2100.2
There are a number of sources of sea-level rise, although the relative contributions of each to the overall effect are still the subject of scientific debate. Probably the greatest contribution, though the one likely to be forgotten by most of us, comes from the thermal expansion of the oceans due to global warming. This is thought to account for about 60 per cent of the currently observed rise. Then there is the more theatrical effect of melting Arctic and Antarctic ice. Melting ice floes do not alter the sea level as they already displace water, but the ice sheets and glaciers on land that melt and run off into the sea make up the remaining 40 per cent. However, these ice sheets and glaciers are thawing faster than was once predicted, and over the next hundred years melting of the Greenland icecap alone could add at least as much again. As white ice melts into blue sea, the Earth’s surface becomes that much darker, and so absorbs more sunlight, producing a greater global warming. In some scientists’ view the reduced reflectivity of the Earth is now beginning to contribute more to global warming than our injection of carbon dioxide into the atmosphere.
A negligible additional factor in rising sea levels is due to melting mountain glaciers in temperate and tropical regions, such as the Himalayas, Andes and the fabled snows of Kilimanjaro, which some have predicted will disappear within as little as ten years. These add 100 cubic kilometres a year to the total, which may be ‘more than the entire volume of Lake Geneva’, but is still almost literally a drop in the ocean in terms of sea-level rise.3 This melting is more significant for the fact that it jeopardizes the water supply upon which many mountainside communities depend. As much as 40 per cent of the world’s population depends ultimately on Himalayan melt-water for its drinking supply, for example.
These figures seem modest: 49 centimetres is about up to the knees, and it’ll take a hundred years, a slow rising tide by any measure. Certainly these figures are not scary enough for the media. Time magazine, in a special report on global warming in April 2006, explained these causes of sea-level rise, but the figure it chose to quote in its text for any actual rise was the 7 metres due to the melting of the entire Greenland ice sheet, ‘swallowing up coastal Florida and most of Bangladesh’. (Elsewhere, a graph presented the accepted IPCC projections without inte
rpretation.)
Fred Pearce, the veteran environment writer for New Scientist, chose the same lurid figure for an article in the magazine in 2000 based on the then forthcoming 2001 report of the IPCC. The piece ran under the preposterous headline ‘Washed off the map: Better get that ark ready because sea levels are gonna rise.’ Former United States presidential hopeful Al Gore’s film, An Inconvenient Truth, spared us the ark but also could not resist the 7-metre deluge.
When the content of the story fails to provide drama, the art department is often happy to help. For instance, the Daily Telegraph in December 2006 reported the view of Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research that sea levels might rise by a metre more than is generally expected over the next century. The article was generously illustrated with montages of sodden London landmarks. One showed water lapping gently against the masts of the Millennium Dome – at least 20 metres above ground level, never mind the usual high tide.
Even a 7-metre rise in sea level will not happen for quite some hundreds of years under the most pessimistic scenario. But this has not stopped even level-headed scientists from joining the more excitable media and showing us what the world would look like in this eventuality – a simple matter of plugging the relevant topographical data into a computer graphics package. The results – typically showing the coasts of Florida or East Anglia or the Netherlands – impose sea levels projected for hundreds of years hence on top of present-day cities and take no account of protective measures that would surely have been implemented during the passing centuries in these wealthy regions.
The morbidly curious might like to know at this point that if all the ice in the world were to melt it would raise the ocean level by 70 metres – a calamity that requires temperatures far in excess of even the most apocalyptic forecasts and even then would take thousands of years to transpire. Although there is not the remotest prospect of this happening, this too is a factoid routinely thrown in to juice up stories on rising sea levels and featured in the recent special reports of Time and The Economist.
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