How bad is it going to get? According to the IPCC sixth assessment report it will not get too bad if global temperatures exceed 1.5 degrees above pre industrial. It will get really bad if the change exceeds 4 degrees.
A 1.7 degree rise in global temperature in 2030 does not seem much worse for people than the climatic conditions of 1991-2005. However, if you believe this you are probably unaware of complex systems behaviour. True, a 1.7 degrees temperature rise is liveable for most of the world provided nothing else happens but something else will happen. This is because major changes in a complex system usually create disturbances throughout the system.
As the population has grown and the interdependence of our economies has increased the global system has become ever more inclined to wild changes. A little war in Ukraine can cause starvation in the Sahel. An escaped virus in Wuhan can depress everywhere.
It turns out that if we invest in production (develop the world) we obtain high populations that collapse. If the world economy is modelled from 1900 to the present day with about 44% of production consumed and the other 56% re-invested we get a fairly accurate picture of the current economy in 2023:
Whereas if we had consumed 39% of output and reinvested 61% we might have had this outcome:
This might seem counter intuitive - surely more investment means more production so people will all get richer. Well, the people in the “39% consumption” model would indeed have got richer than us. At 61% re-investment people might have been twice as rich as now by 1990. Unfortunately exponential growth tends to be followed by exponential collapse.
Mitigating climate change looks like it will cost a lot. Large numbers of power stations and vehicles will need to be replaced. Money will need to be diverted from consumption to investment. The good news is that industrial output could actually increase. The bad news is that this could create an economic collapse as investment is diverted from consumption, agriculture etc. and create a further collapse as non-CO2 pollutants rise rapidly.
The global economic system has become too complex. We will need to take the crash on the chin if it happens. The obvious solutions all have less obvious problems attached to them that may make the crash worse.
The key change that created the overly complex global system was the massive population growth in the past two centuries and especially in the past 50 years. It seems like we have successfully avoided the Malthusian meltdown for over a century by overcoming food shortages, energy supply, disease etc. However, the modelling in global systems models does not show a succession of triumphs over adversity. The “green revolution” is not visible. We only experience a Malthusian meltdown when all the sources of further development become scarce.
It is possible that we have now exceeded the carrying capacity of the planet but it may be possible to put everyone in hutches like in the “Matrix” or avoid depopulation by some other means.
It is best to simply not worry about the future. We will either get a “lucky” break as a result of technological change or some other near miracle or we wont. No doubt there will be a global effort to continue with a very high population by reducing CO2 emissions etc. As humanitarians we can only wish this effort some success.