In early June, I went to visit the Eden Project in Cornwall. It's been open since 2001, so you might wonder just why its taken me so long to get there, as I have been in Cornwall many times over these years. But it seems to me the Eden Project was built as a rainy-day visitor attraction and maybe I had been lucky with the weather up till now. But a wet June day finally saw me cross the threshold, buying tickets for our party of four at an eye watering price, and following the many other rain dodgers down into the gigantic tropical biodome which is its centre piece.
It's bloody hot and humid in there and after about an hour wandering around I was feeling quite exhausted. But also amazed by the sheer scale of the structure. I've been in hot humid glasshouses before — we have several in the Botanical Gardens in Cambridge — but the Eden Project biodome is the size of a large airport terminal. Our party was pleased to get out of it into the relative coolth of the adjacent Mediterranean dome, and even more pleased to get out into the open air half an hour later.
On the way home I started musing about whether the Eden Project has anything to teach us about the impending climate crisis. If we fail to keep the average temperature rise down to manageable levels, we will render much of the Earth's surface uninhabitable. Well much of it already is, let's be frank. But parts which are now readily inhabitable will become too unpleasant to forge a life in. But spaces like the Eden Project, provided they can get good supplies of energy, will continue to function even at very much higher temperatures, because we can create an indoor climate which will be very comfortable for human beings, and indeed, animals and plants.
In a sense these changes are already happening. We are tending to move into cities which are certainly non-natural environments. We already have homes which are already heated and cooled spaces, insulated form the outside environment, and we mostly travel in cars, buses and trains which have controlled environments. Cross what we already are doing with Eden Project type biodomes and you have a viable future landscape. It's a bit like what would happen if we were to colonise another planet where the air wasn't capable of supporting us. There we would have to build an artificial atmosphere around us, as indeed many science fiction writers have postulated. It's as if we were bringing our plans for the colonisation of Mars back down to Earth to tide us through this climate emergency.
The downside to this is that it is unlikely to support the 7 to 10 billion people reckoned to be living on earth by mid-century, not to mention their feedstock animals and plants. These biomes would probably be constructed in places which would be relatively immune to the tempestuous weather we may experience, and on high ground to avoid rising sea levels. Probably away from earthquake and hurricane zones as well, so as to maximise their chances of long term stability.
The wild, untamed outside areas would probably consist of 99% of the Earth's land cover and we would be free to explore these areas, weather and climate permitting. But live there? Not really possible anymore. There might be vast areas used to collect solar and wind energy needed to keep us humans comfortable in our biodomes, or maybe we would have all gone nuclear by then, because no one will be too worried if there is a radiation spill as there will be no one living within 100 miles.
How many people would this sort of future support? I guess that depends on how many of these biodomes we managed to build. But say each biodome was around 10km2, a 3.5km diameter circle. A luxurious one might support as many as 100,000 people (having 10m2 each). That's just about feasible to comprehend. It would be like putting a roof over an entire town.
Of course you would immediately be cast into a world where there would be upmarket biodomes (maybe 25m2 each) and low rent ones (less than 10m2 each). And then there would be those who couldn't afford to live in a biodome and maybe they'd be left to fend for themselves in the wild parts of the planet. Or maybe not....
It would be very expensive to build biodomes of this scale, but what exactly would be the alternative? The most obvious answer is to mitigate - to reduce our dependence on fossil fuels, and keep the whole planet's atmosphere in defined limits so that it is one big functioning biodome. But despite so many people's best wishes, at the moment this seems unlikely, as the political will required to do this is sorely lacking. Another option is to start tinkering with the planet's atmosphere and try and keep it within comfortable bounds. But at the moment, this also seems an unlikely prospect.
Life on Earth will continue, whatever we do to the climate. But just how much life, and under what conditions, is still a very open question.