A sunshade to help southern Africa cope with climate change?

© 3quarks – 123RF.com

So consider the idea of having a giant sunshade over southern Africa. During the recent heatwave, it would have been wonderful. It could have saved lives and there would have been less evaporation from dams, reducing the impact of the current drought. Crops and livestock would have fared better.

Putting up a global sunshade is feasible, not fanciful. It has already been shown to be an option for California. But it is rarely talked about in polite scientific or policy conversation. This is because it would be geoengineering, a human intervention to alter the climate. Many people consider this to be a step too far. But this must change, not least because human action is already causing the climate to change.

Why geoengineering is a difficult subject

Discussion about geoengineering has been muted because scientists are uncomfortable about accepting second class solutions. They fear that any effort to moderate the impact of additional C02 in the atmosphere will reduce the pressure for action on the cause of the problem.

But Africa must look hard at uncomfortable options or face being left behind by other countries with fewer scruples. Specifically, it is important to consider how regional geoengineering initiatives could help to protect southern Africa from some of the more damaging impacts of climate change.

From the outcome of the COP21 meeting in Paris last year, two key points stand out:

1. All countries made a commitment to take action on climate change to avert a global disaster. This was real progress.
   
2. But the practical commitments they made were nowhere near radical enough to achieve the goal of reducing global warming quickly enough.
   

The resulting slow progress means that the southern African region could face prolonged hardship. The consensus is that life under climate change will be hotter, and therefore drier, since evaporation and aridity increases with temperature.

Some countries stand to gain, some to lose

Southern Africa needs to take action as a region. Not all regions are affected equally by climate change.

Some countries - Canada and Russia specifically - actually stand to gain from a warmer globe. Millions of hectares of land that is currently frozen will become available for agriculture. This will occur just as food problems arise elsewhere.

Other countries - think Saudi Arabia - would like to put off action as long as possible. This will enable them to use their oil revenues to fund the adaptation that they will need. Coal exporting countries like Australia and South Africa have similar interests.

Yet another group of countries would like adaptation to move faster. This is not always because they are concerned about the impact of climate change. Many in Europe believe that there is money to be made from renewable energy. And they would like everyone to adopt it as fast as possible so that they can make more windmills, install more solar panels and sell more power management solutions.

So regional interests have a strong influence on the approach to climate change. And I contend that South Africa, together with its neighbours, is not doing enough to consider specific regional interests and options. That opinion is based on more than a decade's engagement on climate issues at the United Nation's Commission on Sustainable Development, two COPs, the World Economic Forum and South Africa's National Planning Commission as well as my work on southern Africa's water resources.

The thinking - or rather the lack of it - about geoengineering is one example of regional interests.

Creating shade

Some geoengineering interventions will only work on a global scale. Proposals to suck carbon dioxide out of the atmosphere are one example. But other interventions work more locally.

It has long been known that the presence of some chemicals in the atmosphere can shield the earth from the heating effects of the sun. This has been demonstrated on numerous occasions when, after erupting volcanoes spewed sulphurous gases and ash, the earth cooled noticeably for a couple of years. The most famous case is perhaps the eruption of Mount Tambora in Indonesia in 1815. This led to 1816 being known as the "year without a summer".

The science to use this effect for geoengineering is now well documented. A leading mind on this is professor Paul Crutzen, who won the Nobel Prize for working out how to fix another global atmospheric problem - the ozone hole.

If sulphur dioxide (SO2) is used, the amount required for a worldwide solar sunshade could be dosed into the atmosphere using existing passenger aircraft. The payload would be the equivalent of two economy class seats on every flight. Crutzen estimated the cost at between $25 and $50 per developed world citizen. It would be more efficient to dose at higher altitudes but the point is that this is already a feasible option.

What needs to be considered is whether this technology could be used to provide local sunshades. These would not help places threatened by rising sea levels which needs warming to be stopped at a global level. But it might well help to reduce the impact of higher temperatures on local agriculture and water resources.

Potential risks need to be considered. The amounts of SO2 needed are tiny compared to what is generated, more harmfully, by industry and natural sources. But it would be desirable to design and use more benign materials. Fortunately, the science of chemistry is increasingly able to design materials with very specific properties. Doing this to mitigate climate change needs to become a research priority.

To make such interventions practical, the region needs local science, focused on meeting local needs. And Western scientists have been reluctant to help develop this capacity. I have found British scientists working on climate change very helpful on many other subjects, but not on this regional interventions. And South Africa's scientists are too often guided by global thinking rather than local challenges and opportunities.

Finally, there is the question of implementation. Do we have the means to do the job? Since there would almost certainly be international opposition to regional geoengineering, we would need regional capacity for intervention. Could this be a new role for embattled SAA? It would be helpful to have a national airline to enable us to take a regional decision to protect regional interests.

Such a move could buy time while the underlying problem is properly addressed. Critics who argue that this would simply encourage further delay miss the point. The delays are happening and the consequences need to be addressed. Beyond that, the mere threat of regional geoengineering action could accelerate action to address the underlying causes more effectively.

At the least, the southern African region if not the continent as a whole must discuss regional options. And regional geoengineering will have to be on the agenda. Otherwise Africa will once again find itself at the back of the queue, carrying the burden and the costs while those responsible for our problems profit from our passivity.