Geo-engineering and climate control

Nitin Desai

The idea of engineering the atmosphere to stave off global warming is increasingly gaining popularity, but it raises several issues

A recent sci-fi novel, Ministry of the Future by Kim Stanley Robinson, describes what will happen in the future as countries fail to agree and implement a carbon mitigation programme that limits the global temperature increase to a manageable level. The novel begins with a massive heat wave in Uttar Pradesh that kills millions. The Government of India then responds by unilaterally launching a move to spray sulphur dioxide on clouds in the Indian Ocean, which would reduce solar radiation and bring the temperature down. The move works and for two-three years the temperature comes down. The novel goes on to elaborate more such measures to cope with the consequences of catastrophic climate change.

This piece of science fiction looks increasingly like a probable projection, given the fact that recent meetings of the Climate Convention, including the one in Egypt, failed to improve the inadequate mitigation agenda that has come out of the Paris Agreement. The Egypt meeting did provide a breakthrough on the so-called loss and damage compensation, which, with the failure to secure an adequate agreement on mitigation, is of some importance, though the notion of liability has been diluted.

What is missing now is the required pressure for strengthening the mitigation commitments. Thus, according to the Sharm el-Sheikh agreement, the work programme for scaling up mitigation has to be “non-prescriptive, non-punitive, facilitative, respectful of national sovereignty and national circumstances, take into account the nature of nationally-determined contributions and not impose new targets or goals”. It would be difficult to draft a deeper dilution of pressure for action than this.

More vigorous action is needed. The November 2022 assessment by the Climate Action Tracker says that, on the basis of current policies and actions, the 2100 temperature will rise by 2.70C from the preindustrial average and about 1.50C from the 2022 level and will continue to increase after 2100. The implementation gap for 2030 is close to 50 per cent. Some modest advances may be realised if the countries do implement their 2030 and long-term targets. But it would now be more prudent to assume that the generations to come will face severe and relatively long heat episodes, floods, droughts and water uncertainty, more storms, sea-level rise, biodiversity loss and much more. Moreover, the risks of climate moving beyond tipping points and threatening the ice cover in the Arctic and Antarctic or melting the permafrost in Siberia and releasing vast quantities of carbon or seriously modifying the monsoon have to be considered.

Does this mean that countries should start looking at the option of reducing the incidence of solar heat through engineering measures as a substitute for mitigation shortfalls? Like a sybarite who keeps drinking alcohol and copes with a stomach upset by taking more antacids!

How well understood is this geo-engineering option? How can it be governed to take account of the fact that the global atmosphere does not respect national boundaries and unilateral actions can have not just beneficial but deleterious effects on other countries? These are questions that need to be answered because several developed countries have started doing research on some geo-engineering options.

Geo-engineering basically compensates for the significant shortfall in mitigation options that are necessary to keep temperature rise below the agreed target level. At present, at the practical level, it is mostly focused on capturing carbon from emissions in high emission plants, like those producing electricity, steel or cement. Carbon capture is a geo-engineering option, but it does not have significant cross-border effects and can be left to the discretion of each country’s mitigation plan.

A more speculative geo-engineering option that is being discussed is the planting of aerosols in the stratosphere, the option chosen by the Government of India in the novel mentioned above. Most aerosols cause atmospheric cooling, either by directly reflecting incoming solar radiation or indirectly through their impact on clouds. They are short-lived in the atmosphere and more regionally variable relative to longer- lived emissions, like carbon dioxide. It is estimated that anthropogenic aerosols alone have cooled global surface temperatures by up to 0.8 °C over the last century. However, their impact is uncertain and certainly does not respect national boundaries. Moreover, there is very little scientific data to assess the impact and the uncertainty.

Stratosphere aerosol injection (SAI) and other measures for solar radiation modification (SRM) are, at present, largely theoretical in nature as they have not been tried on a pilot basis to assess their impact, not just on reducing the incidence of solar radiation but also other side effects like impact on precipitation or the ozone layer. Solar radiation also does not respect national boundaries and any SAI or SRM action will have cross-border effects.

Hence, if these geo-engineering options are to be considered legitimate there must be two crucial moves to bring countries together. The first one, that can be set up now or assigned to the Intergovernmental Panel on Climate Change is a cooperative scientific research process to analyse available information for major volcanic eruptions that altered solar radiation and to plan and evaluate pilot experiments, which must be multilaterally approved. The second requirement is to agree on a global agreement that prohibits unilateral action and sets up a process for multilateral agreement on geo-engineering initiatives. This could be done later after the scientific research process has clarified the potential impact and assesses the desirability of implementing specific SRM options.

The actual implementation of geo-engineering will happen only when extreme climate events like high heat waves start happening and that is way into the future. Also, it will be required only if there are concerns that greenhouse gas reduction will not go at the pace required to keep the temperature increase down to 1.50C. But even though the application of the results of research, if at all, will only take place decades into the future, the process of establishing a credible multilateral process for dialogue and decision must start soon because the risk of wrong decisions is very high. Perhaps the European Commission can take the lead in this as it will require an inter-country mechanism even for its own inter- membership decision on this issue.

A word, however, to climate activists — a global move on geo-engineering is a precautionary measure and should not dilute the pressure on major emitters to do more to reduce their carbon emissions.