I recently attended an absolutely superb seminar given by Prof. Edward Parson on geo-engineering. I occasionally hear interesting things about some of the possibilities on my favourite science podcasts from the Guardian Science, Scientific American and Nature but it is not really a topic I know much about. I learnt some fascinating things from this seminar.
Some simple examples of geo-engineering include painting roads and house roofs white so that they reflect the sun. More advanced examples include putting reflexive (e.g. sulphur) particles into the stratosphere which can reflect heat. As it happens, there is an article on today's BBC suggesting that cloud whitening towers could be built to slow warming across the Arctic.
The single main message that geo-engineering massively widen the climate possibilities, in both the good and bad directions. In the best case, it may have the capacity to solve global warming. In the worst case scenario, it can wipe humanity off the face of the earth and re-create 'snowball earth'.
* Within a couple of years it can achieve the kind of cooling that it would take decades of carbon capture to achieve. And this an be achieved by putting reflexive particles into the atmosphere from almost anywhere. We know this because Mount Pinatuba erupted it cooled the earth by around half a degree Celsius and this lasted for a few years.
* It is cheap. The direct costs of doing this are probably just a few billion dollars a year. Basically nothing.
* When placed into the lower atmosphere they could reduce some of the more local effects of climate change such as tornadoes, floods etc.
* They don't solve everything. As pointed out by The God Species (one of my favourite books on climate change), the earth has many boundaries and crossing any one of them can have severe consequences.
* These technologies do not control earth and water temperatures in the same way so we are left with a much drier earth. This could effect things like the monsoon upon which billions of people rely.
* There may be ozone depletion which is worse that currently estimated. We will make the sky whiter and we are putting acid into the sky which will come down in the rain.
One option would be to use geo-engineering to buy time or just on a local level. But this itself carries the human-behaviour risk that we come to rely on these technologies and don't make the efforts we should to reduce climate change. In addition, if we use geo-engineering to, say, keep the planet 5 degrees cooler than it would be given the pollution we cause, and then one day we are unable or unwilling to use the technology, the earth would very suddenly gain those 5 degrees with all of the consequences.
We then have issues related international cooperation and conflict. Who has the right to decide to use this technology? Many large, wealthy and technologically advanced countries have the ability to do this and there would be winners and losers. Could it create international conflict? Could it be used as a tool for international conflict? If a country or group of countries take the lead, even if it is with the best intentions, there would be some losers. How do we compensate those losers? What if something goes wrong, the leaders could be blamed for it and perhaps accused of deliberately behaving in a malevolent way even when no such intentions existed.
How do we create international laws and institutions which are capable of addressing these issues?
On the other hand, without this option, we could be heading for disaster already. We could behave badly and take humanity on a path to destruction. But we could also simply be unlucky. Even if we do everything we should do, climate change might still place human existence in peril. If we arrive at this point and have not already tested this technology, then we risk either not being able to develop it quickly or using it in a dangerous way.
Therefore, we somehow want to have the option to use this technology. BUT without it in any way causing a moral hazard problem - i.e. without it changing human behaviour. Knowing that we MIGHT be able to call on this in the future is not a good reason not to behave correctly now. AND we need to be able to think carefully about the scientific and institutional international context including all of the risks. Geo-engineering has the capacity to save humanity or kill us. Abandoning it has severe consequences and so might developing it if we are unable to manage it. Should be fun to watch the scientific progress and follow the emotional debates it will generate.