Podium: Climate change is inevitable. We must adapt to it

If geoengineering is defined as purposeful human activity that significantly alters the state of the Earth, we became geoengineers soon after we started using fire, for cooking, land clearance and smelting bronze and iron. During this long engineering apprenticeship, we changed the Earth, but until quite recently, we were unaware that we were doing it, still less the adverse consequences.

Before we use geoengineering as a means of mitigating the consequences of climate change, then, we have to raise the following question: are we sufficiently talented to take on what might become the onerous permanent task of keeping the Earth in homeostasis?

Consider what might happen if we start by using a stratospheric aerosol to ameliorate global heating; even if it succeeds, it would not be long before we face the additional problem of ocean acidification. This would need another medicine, and so on. We could find ourselves in a Kafka-like world from which there is no escape.

Whatever we do is likely to lead to death on a scale that makes all previous wars, famines and disasters small. To continue business as usual will probably kill most of us during the century. We have to consider seriously that, as with 19th century medicine, the best option is often kind words and painkillers but otherwise to let Nature take its course.

The usual response to such bitter realism is: then there is no hope for us, and we can do nothing to avoid our plight. This is far from true. We can adapt to climate change and this will allow us to make the best use of the refuge areas of the world that escape the worst heat and drought. We have to marshal our resources soon and if a safe form of geoengineering buys us a little time then we must use it.

Parts of the world such as oceanic islands, the Arctic basin and oases on the continents will still be habitable in a hot world. We need to regard them as lifeboats and see that there are sufficient sources of food and energy to sustain us as a species. Physicians have the Hippocratic Oath; perhaps we need something similar for our practice of planetary medicine.

Perhaps the saddest thing is that if we fail and humans become extinct, the Earth System, Gaia, will lose as much as or more than we do. In human civilisation, the planet has a precious resource. We are not merely a disease; we are, through our intelligence and communication, the planetary equivalent of a nervous system. We should be the heart and mind of the Earth not its malady. Perhaps the greatest value of the Gaia concept lies in its metaphor of a living Earth, which reminds us that our contract with Gaia is not about human rights alone, but includes human obligations.

Taken from an article in Philosophical Transactions of the Royal Society, focusing on geoengineering to avert climate change