The other day I was a virtual attendee at a workshop in Colorado. The main topic of discussion was ‘climate intervention‘. Climate intervention is deliberate human activity aimed at changing the climate – typically with a view to ameliorating the effects of climate change. There are various technologies that could be used for this purpose, from planting trees through injecting chemicals (such as sulfur dioxide) into the stratosphere, to putting giant reflectors in space.

I was not ready for the impact the discussion of all this would have on my emotional state. Though I have attended academic events on the general theme of sustainability for several years, this was the first climate change specific event I’d been to. Though I see from my smartwatch data that my heart rate was no greater than normal when working, I did find myself experiencing a rising sense of panic. A lump was in my throat, and I could not settle in the evening. I did not want us to undertake these interventions.

Neil Stephenson‘s book ‘Termination Shock‘ explores a scenario around geoengineering. I don’t want to give away too much of the plot, but the main point I want to make anyway is that this meeting I was attending was essentially discussing seriously something that has been the subject of a relatively recent science fiction novel. Neil Stephenson foresaw the metaverse in my favourite book, Snow Crash. I hope Termination Shock isn’t another dystopian prophesy.

The motivation for undertaking such drastic action is clear in the opening passages of another cli-fi book, The Ministry for the Future, by Kim Stanley Robinson. These passages contain a scene in which millions are killed by a heat wave that is unsurvivable without air conditioning, which leads to a power cut. We concentrate a lot on temperature when discussing the climate. It is 1.5C we are trying to limit ourselves to, and when we fail as we are expected to do before the end of the decade, every 0.1C of mean annual global surface temperature increase we prevent is still important. No mention of humidity, however, which is important for two reasons. First, increasing mean annual temperature and increasing humidity are expected to coincide as warmer air can hold more moisture. Second, the combination of heat and humidity is what kills us through hyperthermia.

So-called ‘wet bulb’ temperatures above 35C lead to the human body being unable to cool itself through sweating, and breaching this threashold is made more likely through climate change. Of course, it’s not like a 34.9C wet-bulb temperature is fine, and 35C is fatal. Heatwaves with 28C wet bulb temperature led to high excess deaths in Europe. However, 35C wet bulb is the point at which even a healthy person cannot maintain their body at the right temperature due simply to the laws of physics, with death in hours.

There is, then, a risk as the climate warms, that more parts of the world will become uninhabitable to humans without appropriate accommodation and technology. Since higher humidity is associated with coastal areas, where many of the world’s largest cities are located, these problems will be faced by more populous areas, creating pressure for migration, building and infrastructure design, energy use, technology development, and geoengineering. Essentially, we build ecocyborgs in these areas, people living there run away to more inhabitable parts of the world, and/or we modify the whole world’s climate in the opposite direction to that we’ve been doing since the Industrial Revolution. Of these, only migration avoids choices that entail learning how to make uninhabitable areas inhabitable on the kind of large scale that would be needed for humans to live on other planets than Earth. Our behaviour is putting us into a corner in which ecocyborgs and planetary-scale geoengineering become necessary for our survival.