Kyoto2

How to Manage the Global Greenhouse

By Oliver Tickell

Zed Books Ltd

Copyright © 2008 Oliver Tickell
All rights reserved.
ISBN: 978-1-84813-025-8

Contents

List of boxes, vi,
Acknowledgements, vii,
Introduction, 1,
Kyoto2 summary, 8,
1 What’s the problem?, 17,
2 The policy response, 30,
3 The atmospheric commons, 68,
4 Applying market economics, 81,
5 Non-market solutions, 139,
6 Allocating resources, 169,
7 The Great Dying, 215,
8 Questions and answers, 224,
Notes, 250,
Glossary, 266,
Index, 280,

CHAPTER 1

What’s the problem?

‘The primary scarcity facing the planet is not of natural resources nor money, but time.’ International Energy Agency

‘We would be taking a great risk with future generations if, having received this early warning, we did nothing about it or just took the attitude: “Well! It will see me out!”‘ Margaret Thatcher

‘Society may be lulled into a false sense of security by smooth projections of global change.’ Tim Lenton

‘The doomsday clock of climate change is ticking ever faster towards midnight.’ Prince Charles

‘Moderate slowing of fossil fuel use will not appreciably reduce long-term human-made climate change. Preservation of climate requires that most remaining fossil fuel carbon is never emitted to the atmosphere.’ Jim Hansen

The Earth is heating up, and fast. The Intergovernmental Panel on Climate Change (IPCC) has reported that eleven of the last twelve years (1995–2006) rank among the twelve warmest years since 1850. Meanwhile greenhouse gases have been building up in the atmosphere faster than even the highest ’emissions scenarios’ put forward by the IPCC in 1995.

So have temperatures and sea level rises – as reported by Stefan Rahmstorf, Professor of Ocean Physics at Potsdam University, himself an IPCC lead author on the physical science of climate change. Sea levels have risen by an average of 1.8mm per year since 1961, rising to 3.1mm per year since 1993, as a result of melting glaciers, ice caps and the polar ice sheets, and the thermal expansion of ocean waters. Rahmstorf’s analysis of climate trends compared to the projections of the IPCC’s 2001 Assessment Report shows that temperature rise is at the top end of the predicted range, while sea level rise is significantly greater than even the highest predictions.

Thus ‘the climate system, in particular sea level, may be responding more quickly to climate change than our current generation of models indicates’, he writes, adding that the IPCC’s climate projections ‘have not exaggerated but may in some respects even have underestimated the change, in particular for sea level’.

One sign of this temperature rise is the rapid growth of the tropical climate zone – since 1980 it has expanded by 275 kilometres to north and south, as described by Dian Seidel of the US National Oceanic and Atmospheric Administration. Again, Seidel notes that the observed recent rate of expansion is greater than predicted by climate model projections. This could lead to ‘profound changes in the global climate system’. In particular the poleward movement of atmospheric circulation systems, such as jet streams and storm tracks, ‘could result in shifts in precipitation patterns affecting natural ecosystems, agriculture, and water resources’.

There are now many indications that the world is entering into a phase of accelerated global heating – one in which ‘positive feedback’ processes in the Earth’s climate system play an increasingly important role as drivers of further heating. This danger was highlighted by James Lovelock, originator of Gaia theory, at a packed Royal Society public lecture in which he spoke of the unprecedented melting of Arctic sea ice during the 2007 summer. Because ice reflects 80 per cent of the sun’s heat, while open water absorbs 95 per cent, the melting sea ice creates a positive feedback that leads to even more heating, which in turn leads to even more melting, and so on. Thus:

We have to understand that the Earth System is now in positive feedback and is moving ineluctably towards the stable hot state of past climates. I cannot stress too strongly the dangers inherent in systems in positive feedback. Imagine a wooden house whose occupants have built too large a fire to warm them and the furniture near the fire was smouldering. If they did not act immediately, positive feedback would ensure that the whole house was consumed by fire in minutes.

This heating is self-reinforcing and the effects carry over from year to year, as Jim Hansen – director of the NASA Goddard Institute for Space Studies and Professor of Earth and Environmental Sciences at Columbia University – explained to the Iowa Utilities Board. ‘As the warming global ocean transports more heat into the Arctic, sea ice cover recedes and the darker open ocean surface absorbs more sunlight,’ he said. ‘The ocean stores the added heat, winter sea ice is thinner, and thus increased melting can occur in following summers, even though year-to-year variations in sea ice area will occur with fluctuations of weather patterns and ocean heat transport.’

And the heating of the Arctic Ocean is especially dangerous as it will also heat up the Greenland Ice Sheet and cause it to melt faster than anticipated. This could cause some metres of sea level rise during this century, and would ultimately lead to 7 metres of sea level rise once its 3 billion cubic kilometres of ice have melted away. It has always been assumed that the melting or disintegration of this massive volume of ice would take millennia to occur, but recent observations show that this is not so. While it takes millennia for an ice sheet to build up, writes Hansen, it can give way with surprising speed since multiple positive feedbacks accelerate the process once it is under way. ‘Snow-covered ice reflects back to space most of the sunlight striking it. However, as warming causes melting on the surface, the darker wet ice absorbs much more solar energy. Most of the resulting melt water burrows through the ice sheet, lubricates its base, and thus speeds the discharge of icebergs to the ocean.’

Further positive feedbacks take place where ice sheets meet the sea or ocean. Warming sea water accelerates melting, and rising sea levels tend to lift the ice and destabilize it further: effects that may be at work at the massive Pine Island ice sheet in West Antarctica, where the British Antarctic Survey reports a surge in the speed of its seaward descent.

The rate of ice sheet melt in West Antarctica along the Bellingshausen and Amundsen seas has also increased by 59 per cent in ten years to reach an estimated 132 Gt/y (gigatonnes per year) in 2006, according to Eric Rignot, Principal Scientist for the Radar Science and Engineering Section at NASA’s Jet Propulsion Laboratory, while ice sheet losses on the Antarctic peninsula increased by 140 per cent to reach an estimated 60 Gt/y. ‘Losses are concentrated along narrow channels occupied by outlet glaciers and are caused by ongoing and past glacier acceleration,’ he reports. ‘Changes in glacier flow therefore have a significant, if not dominant, impact on ice sheet mass balance.’

Likewise in Greenland, ice sheets are melting away at unprecedented rates, as reported by Edward Hanna of Sheffield University’s Department of Geography. Summer 2003 was the warmest since at least 1958 in coastal southern Greenland, 2005 was the second warmest and 2006 the third warmest. In 2005 Hanna observed ‘the most extensive anomalously warm conditions over the ablation zone of the ice sheet, which caused a record melt extent’, and 2006 saw the third-highest run-off in forty-nine years from ice sheet melting. He and his co-authors ‘attribute the significantly increased Greenland summer warmth and Greenland Ice Sheet melt and runoff since 1990 to global warming’.

Hansen notes that these dramatic increases in polar ice melt have taken place under a warming of under 1°C since pre-industrial times. Thus ‘Global warming of several more degrees, with its polar amplification, would have both Greenland and West Antarctica bathed in summer melt for extended melt seasons.’ He concludes that we need to constrain greenhouse gas emissions far more sharply than is presently considered feasible by policy-makers. While recognizing that sea level changes from ice melt are inherently unpredictable, he writes,

I find it almost inconceivable that BAU [business as usual] climate change would not yield a sea level change of the order of meters on the century timescale. The threat of a large sea level change is a principal element in our argument that the global community must aim to keep additional global warming less than 1°C above the 2000 temperature, and even 1°C may be too great. In turn, this implies a CO2 limit of about 450 ppm, or less. Such scenarios are dramatically different than BAU, requiring almost immediate changes to get on a fundamentally different energy and greenhouse gas emissions path.

This view is supported by Rahmstorf, who projects a sea level 0.5m to 1.4m higher in 2100 than in 1990. He also believes that the uncertainties over future sea-level rise are larger than previously estimated. ‘A rise of over im by 2100 for strong warming scenarios cannot be ruled out,’ he argues, ‘because all that such a rise would require is that the linear relation of the rate of sea-level rise and temperature, which was found to be valid in the 20th century, remains valid in the 21st century.’ As such the very low sea-level rise values reported in the IPCC’s Third Assessment Report ‘now appear rather implausible in the light of the observational data’.

Arctic heating will also warm the tundra regions of the Canadian, Siberian and Alaskan Arctic, with the risk of emitting billions of tonnes of methane – a greenhouse gas some thirty times more powerful than carbon dioxide – presently locked up in the permafrost (see also Chapter 7). Indeed, this process may already be under way in western Siberia, which has warmed by 3°c over the last forty years, as reported by Fred Pearce in New Scientist:

An area stretching for a million square kilometres across the permafrost of western Siberia is turning into a mass of shallow lakes as the ground melts, according to Russian researchers just back from the region. The sudden melting of a bog the size of France and Germany combined could unleash billions of tonnes of methane, a potent greenhouse gas, into the atmosphere. […] The warming is believed to be a combination of man-made climate change, a cyclical change in atmospheric circulation known as the Arctic oscillation, plus feedbacks caused by melting ice, which exposes bare ground and ocean. These absorb more solar heat than white ice and snow.

Likewise in the interior of Alaska, reports F. Stuart Chapin, Professor of Ecology at Alaska University, warming has triggered pronounced ecological and social change. Since 1950 air temperatures have increased by 0.4°C per decade, and are projected to rise even faster in the future; the growing season has lengthened by 2.6 days per decade, and permafrost has warmed by 0.5°C per decade. A large part of the problem is that warming ‘is amplified at high latitudes as reflective sea ice, glaciers, and snow cover are replaced by heat-absorbing water, land, and forests’.

If these trends continue and spread to other Arctic regions, the ‘runaway greenhouse effect’ – in which cascades of positive feedback cycles become the main, and growing, drivers of heating – will be well out of control. And if that point is reached, humanity can reduce its greenhouse gas emissions to zero without making any difference: the ‘climate roller-coaster’ (to borrow a phrase from George Marshall’s Carbon Detox) will be well and truly under way, and we had better hold on tight.

Another positive feedback process now under way is that oceans are absorbing less of the CO that we put into the atmosphere. That leaves more in the atmosphere to contribute to global heating – the so-called ‘airborne fraction’. As Josep Canadell, Executive Director of the Global Carbon Project, reports, CO2 emissions are rising sharply thanks to a combination of economic growth and the increasing carbon intensity of the global economy since 2000, which means that ‘comparing the 1990s with 2000–2006, the emissions growth rate increased from 1.3% to 3.3% per year’.

But the trend is accentuated because oceans and forests are also taking up less of the CO2 we emit, leading to an increased airborne fraction. This is currently about 57 per cent, with the remaining 43 per cent absorbed in soils, oceans and biomass. Canadell cites convincing evidence of a long-term trend over the last fifty years of ‘a decline in the efficiency of CO2 sinks on land and oceans in absorbing anthropogenic emissions’. The effect is hard to quantify, but could be responsible for as much as a third of the increase in atmospheric CO2. ‘An increasing [airborne fraction] is consistent with results of climate-carbon cycle models,’ he concludes, ‘but the magnitude of the observed signal appears larger than that estimated by models. All of these changes characterize a carbon cycle that is generating stronger-than-expected and sooner-than-expected climate forcing.’

Specific information has emerged regarding the reduced absorption of CO2 by tropical forests, as reported by Kenneth Feeley, Fellow of Harvard University’s Center for Tropical Forest Science, with significant declines in stem growth rates at tropical forest sites in Panama and Malaysia. Changes in growth were ‘significantly associated with regional climate changes’, and growth rates went down as average mimimum temperatures went up. ‘While the underlying cause(s) of decelerating growth is still unresolved,’ he reports, ‘these patterns strongly contradict the hypothesized pantropical increase in tree growth rates caused by carbon fertilization.’

The findings are consistent, however, with a new coupled atmosphere-vegetation model of the world’s greatest tropical forest, the Amazon, by Kerry Cook and Edward Vizy of Cornell’s Department of Earth and Atmospheric Sciences, which also indicates that rising atmospheric CO2 will lead to significant declines in forest cover. If atmospheric CO2 levels rise to 757ppm, the model projects reduced rainfall, alterations in seasonal cycles and a weakening of tropical circulation systems, resulting in ‘a 70% reduction in the extent of the Amazon rain forest by the end of the twenty-first century and a large eastward expansion of the caatinga vegetation that is prominent in the Nordeste region of Brazil today’.

The role of the Southern Ocean as a carbon sink is also weakening, according to Corrine Le Quere, Professor of Environmental Sciences at the University of East Anglia, who estimates that its capacity to absorb carbon from the atmosphere is reducing at a rate of 80Mt (megatonnes) of carbon (about 300Mt of CO2) per year each decade. She puts this down to the increasing wind speeds over the Southern Ocean – itself a result of global warming. ‘Consequences include a reduction of the efficiency of the Southern Ocean sink of CO2 in the short term (about 25 years) and possibly a higher level of stabilization of atmospheric CO2 on a multicentury time scale.’

These are all examples of ‘tipping points’ in the Earth’s climate system – defined by Le Quere’s colleague at UEA, climate scientist Tim Lenton, as ‘critical thresholds at which a tiny perturbation can qualitatively alter the state or development of a system’. Thus, ‘at a particular moment in time, a small change can have large, long-term consequences for a system’.

‘Human activities may have the potential to push components of the Earth system past critical states into qualitatively different modes of operation, implying large-scale impacts on human and ecological systems,’ warns Lenton. ‘Our synthesis of present knowledge suggests that a variety of tipping elements could reach their critical point within this century under anthropogenic climate change. The greatest threats are tipping the Arctic sea-ice and the Greenland ice sheet, and at least five other elements could surprise us by exhibiting a nearby tipping point.’

These other tipping points include disruptions to ocean circulation – which could, for example, cause the North Atlantic Drift or Gulf Stream current, which warms northern Europe (including Britain), to submerge farther south than it now does. The failure of the Gulf Stream could bring glacial conditions to northern Europe, even while the rest of the Earth warms. And we know from analysis of ancient ice layers in the Greenland ice sheet that temperature swings of 8–10°C (known as ‘Dansgaard-Oeschger’ events) have taken place more than twenty times during the past glacial period. As Rahmstorf warns, ‘The Greenland ice contains a clear warning: the climate system is by no means a sluggish, good-natured sloth – it can react very abruptly and violently.’

The increasing evidence of positive feedback cycles in global warming leads Lovelock to conclude that reducing our carbon emissions is not enough. We also need to restore our increasingly damaged biosphere, since ‘by abrading the skin of our planet to provide farm land we have destroyed more than 40 percent of the Earth’s natural ecosystems and these were what previously served to sustain a stable climate’. He also believes that we must research ‘geoengineering’ solutions (see Chapter 6), because these may represent our final line of defence against the ‘runaway greenhouse effect’.

(Continues…)Excerpted from Kyoto2 by Oliver Tickell. Copyright © 2008 Oliver Tickell. Excerpted by permission of Zed Books Ltd.
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