Part 10 (1/2)

Scenario values This scenario is premised on: * achieving a safe climate in the interests of all people, all species, and all generations; * a low acceptance of risk, as found in best-practice engineering; and * applying the principle of 'double-practicality' - action must happen in the real world and that must fully solve the problem - and the att.i.tude that 'failure is not an option'.

The conundrum At a practical and physical level, the scenario is based on a conclusion that has been drawn from the science that a safe-climate future is not possible if the Arctic icecap is permanently absent during the northern summer.

It is estimated that, to restore the Arctic ice, the global temperature needs to drop by at least 0.3 degrees from the 2008 level, and that the long-term level of greenhouse gases in the air needs to be in the range of 300325 per million parts of carbon dioxide. To achieve this cooling, we need to set a greenhouse-gas emissions target at zero, and take other significant measures as well. In total, we need to draw about 200 billion tonnes of carbon out of the atmosphere, in order to reduce the heating effect of excess carbon dioxide already in the air, which will in turn fully restore the Arctic icecap in summer.

However, as we cut carbon dioxide emissions, we also reduce the release of aerosols that accompany fossil-fuel combustion. Aerosols, on average, act as a cooling agent in the atmosphere, but are washed out of the lower atmosphere within two weeks; on the other hand, carbon dioxide is only removed from the atmosphere very slowly, and acts as a warming agent for hundreds of years. So if we stop burning fossil fuels, there will be a once-off temperature increase of at least 0.7 degrees, because the acc.u.mulated effect of past carbon emissions continues at the same time as the cooling effect of recently emitted aerosols is rapidly lost.

This spike in temperature could be partially, but not fully, offset if a major effort is made to reduce the emission of short-lived greenhouse gases, such as methane and releases of black carbon.

The removal of atmospheric carbon dioxide can be accomplished by growing bioma.s.s, converting it to biochar (which is largely carbon), and sequestering it in agricultural soils; or it can be accomplished by fully combusting the bioma.s.s, and sequestering the carbon dioxide in geological structures. Simply regrowing forests as a way of storing carbon will not produce enough cooling. Even large-scale biochar production, or combustion and sequestration methods, could take a large number of decades - perhaps as long as a hundred years or more - to initiate effective cooling. As more of Greenland melts and rising temperatures prompt other warming effects, even a transition of decades will prove to be too slow.

What action should we take?

At the time of writing, there were no scientific estimates in the peer-reviewed literature stating exactly how quickly the industrial restructuring and climate-system-change process would take to achieve a safe climate. The Climate Code Red scenario a.s.sumes that the industrial transformation needs to be as fast as can be made possible, for the following reasons: * the planet is already too hot, as is now particularly evident in the Arctic; * high rates of temperature increase will tear apart natural ecosystems; * extreme weather events and climate changes are already debilitating many people and nations; and * there are many unpredictable possibilities that could arise as a result of current greenhouse-gas levels and near-term temperatures: they may destabilise the tropical rainforests and cause their collapse after severe fire; they may destabilise the West Antarctic ice sheet and lead to a catastrophic release of ice into the oceans; and they may cause natural-system warming feedbacks so strong that human efforts to orchestrate cooling will no longer countervail the warming forces.

The fastest restructure of a modern economy occurred during the Second World War, and it seems likely that, with full mobilisation, the industrial restructuring that is needed could be completed in about a decade. The Climate Code Red scenario a.s.sumes that society will, in due course, attempt to complete such an economic restructuring. This will stop greenhouse-gas levels in the air from rising, and will initiate the accelerated removal of excess carbon dioxide from the air; however, in view of the damage already being done by climate change, the beneficial effects of this transformation will almost certainly be too slow in coming.

Two key issues arise in this scenario: * we have to stop emitting greenhouse gases quickly, because the more we emit, the bigger the eventual temperature rise will be; however, in cutting greenhouse gases that are generated by combusting fuels, the aerosol effect will cause a serious short-term temperature rise; and * we must stop the temperature from rising too fast, or too far, and we cannot allow high temperatures to persist for too long, otherwise too much damage will be done.

In light of these issues, we will need to apply additional strategies. Direct cooling strategies that work by increasing the reflectivity of the Earth are most likely needed. These include taking actions that increase the cover of highly reflective cloud (for example, by boosting plankton growth in the oceans or by re-establis.h.i.+ng forests), or injecting aerosols into the upper atmosphere (where they are not washed out by rain), which will also boost reflectivity.

In the last 50 years, humans have been unintentionally geo-engineering the Earth on a huge scale by releasing into the air large quant.i.ties of greenhouse gases and partially countervailing aerosols. Enormous care will be needed to determine the extent to which direct cooling is needed, and to design and select direct cooling methods that can produce clear-cut environmental benefits. The use of temporary intentional geo-engineering for cooling purposes must not be used as an excuse to prolong the release of carbon dioxide.

Economic and political consequences Under the Climate Code Red scenario, there are three enormous tasks that will absorb a sizeable portion of the global economy's productive capacity, particularly during the decade or so in which the bulk of the physical restructuring takes place: the global move to zero greenhouse-gas emissions in as short a period as is environmentally safe, the drawing down of many billions of tonnes of carbon from the air over the fewest possible number of decades, and the direct cooling of the Earth for as long as necessary. Directing a necessarily large part of the economy to the task of creating a safe climate is not seen as being possible under normal political conditions.

The physical success of the scenario depends on sufficient action being taken by nations that produce most of the emissions and that have the economic and physical capacity to contribute to the drawdown of carbon dioxide and to direct cooling. To make this commitment socially possible, we a.s.sume that nations will conclude that they need to go into emergency mode; but the type of emergency action needed is of an unprecedented form.

The dynamics of the climate-change challenge are different from those of the Second World War, during which the threat was palpable from the beginning. While many societies are now feeling significant climate impacts, the largest effects of the current level of greenhouse gases will be felt several decades into the future, and so the degree of action that is necessary now is much stronger than is justified by current impacts alone.

All countries, no matter what their political system, whether liberal-democratic or not, will struggle to achieve the needed change unless they engage their communities in a deliberative process to learn about the climate-change issue, and help them to reach a genuine understanding of the severity of the problem and the necessity for urgent action on a huge scale.

Questions to ask about the Climate Code Red scenario 1. How valid is the a.s.sessment of the climate science? Could the threat be as serious as is argued in Climate Code Red?

2. Is it possible to avoid or reverse dangerous tipping points such as Greenland ice-sheet disintegration, sizeable permafrost carbon emissions, or the catastrophic conversion of rainforests (that is, the conversion of the Amazon to savannah gra.s.sland) if the Arctic remains free of sea-ice in summer?

3. Who could give a well-informed a.s.sessment of the science arguments in Climate Code Red, given that much of the science relied on goes beyond the current IPCC consensus?

4. If the scientific conclusions of Climate Code Red are reasonable, are the proposed responses appropriate? For example: * How necessary are the ethics of creating policy for the benefit of 'all people, all species, and all generations', and the ethics of being risk averse?

* Is the idea of going for a 'safe climate' rather than just avoiding dangerous (catastrophic) climate change a sound response?

* How accurate is the idea that the required solutions go so far beyond business-as-usual that a sufficient response is possible only by establis.h.i.+ng the problems as an emergency?

5. How might the problems of the aerosol conundrum, or of establis.h.i.+ng a cooling mechanism at a sufficient pace and scale, be resolved?

6. How could the detailed action specifications of the Climate Code Red scenario be improved?

7. Will your organisation take a proactive position on a 'safe-climate' future, or will it act neutrally, or in opposition, to such a future?

8. Will your organisation prepare itself to prosper, or function well, in a 'safe-climate' future?

Note: Updated versions of the scenario will be available at ment was reported by J. Amos, 'Arctic sea ice ”faces rapid melt''', BBC News, 12 December 2006. The March and May 2007 studies are M. C. Serreze, M. M. Holland et al. (2007) 'Perspectives on the Arctic's shrinking sea ice cover', Science 315: 153336; and J. Stroeve, M. M. Holland et al. (2007) 'Arctic sea ice decline: Faster than forecast?', Geophysical Research Letters 34: L09501.

The Was.h.i.+ngton Post article on 22 October 2007 is 'At the poles, melting occurring at an alarming rate' by Doug Struck. Regular updates and announcements from the NSIDC are available at nsidc.org/arcticseaice/news. Data on ice thickness was presented by Wieslaw Maslowski to an American Meteorological Society Environmental Science Series Seminar as 'Causes of changes in arctic sea ice' on 3 May 2006.

Walt Meier and Doug Serreze's comments on tipping points were reported in The Independent on 15 August 2007 by S. Connor and on 22 September 2007 by M. McCarthy. Connor also reported on Ron Lindsay's hypothesis on 29 December 2006. Ted Scambos' remarks were made in a personal communication on 21 September 2007, and Struck's Was.h.i.+ngton Post article of 22 October 2007. Tim Flannery's comments appeared in The Age on 28 October 2006.

Changes in Arctic conditions: W. Maslowski, J. Clement et al. (2006) 'On oceanic forcing of Arctic climate change', Geophysical Research Abstracts 8: 05892; D. K. Perovich, J. A. Richter-Menge, et al. (2007) 'Arctic sea ice melt in summer 2007: Surface and bottom ice ablation', Eos Trans. AGU 88(52) Fall Meet. Suppl., Abstract C21C-07; '”Warm wind” hits Arctic climate', BBC News, 18 October 2007.

Sea-ice loss predictions: Louis Fortier M. White, '”Frightening” projection for Arctic melt', Ottawa Citizen, 16 November 2007; Wieslaw Malowski J. Amos, 'Arctic summers ice-free ”by 2013”', BBC News, 12 December 2007; Jay Zwally A. Beck. 'Arctic's record melt', Sydney Morning Herald, 14 December 2007; Josefino Comiso M. Inman, 'Global warming ”tipping points” reached, scientist says', National Geographic News, 14 December 2007.