Thread by @SteB777

1) Let me explain the problem with this tweet. @ClimateOfGavin accuses @ClimateBen of exaggeration. The problem is Gavin's certainty that Ben is wrong. He is actually doing what he is criticising Ben for.

https://twitter.com/ClimateOfGavin/status/1386507724154888192

2) As the levels of warming get greater, it becomes more and more difficult to predict what the impacts will be on both human society and civilization, and life in general i.e. both biodiversity.

3) To an extent, climate modellers like @ClimateofGavin can model physical systems like the climate, because whilst a complex system, it does have simplistic components which allow it to be modelled.

4) However, if you try to model things like impacts on human society, or biodiversity, it becomes almost impossible to produce any realistic model, because of bifurcation points, where a parameter in the system being modelled, could go in totally different directions.

5) Let's take Ben's statement "Most humans dead by 4C". The ecological carrying capacity of the Earth as regards sustaining the human population, does not rely solely on crop yield etc, but the organization of human society.

6) To feed 8 billion people relies on complex supply chains i.e. a complex economy and world order, which did not exist prior to the industrial revolution. The human population prior to the industrial revolution, was much less than 1 billion people.

7) This less than 1 billion human population prior to the industrial revolution was probably close to the carrying capacity of the Earth based on the state of the organized economy which existed at the time.

8) The present state of the global economy is not fixed. It all holds together because people are all working towards one goal of economic growth. It would be quite possible for the current economic and global governance system to collapse.

9) There could be many things that could cause the collapse of the present economic, financial and governance system from the climate and ecological crisis, some sort of collapse of the financial system, to natural disasters, nuclear war etc.

10) If some sort of event triggered this collapse, we wouldn't necessarily just get back to where we were before. Historical precedent demonstrates that when civilizations collapse, there is not necessarily a rapid return to the previous state.

11) Take the collapse of the Roman Empire, and the "Dark Ages" that followed. It took close to a 1000 years for Europe to return to a similar level of technology, organization and trading. Roman cities had complex water supply systems and even sewage systems.

12) This is a serious problem with modern human society, which relies on complex long supply chains, to not only supply food, but to supply fuel and synthetic fertilizer to facilitate industrial farming. With some sort of organizational collapse, this would not be possible.

13) In other words with a collapse in the present organizational system of human society, call it the modern civilization we simply wouldn't be able to feed the present population. We wouldn't be able to produce that much food, yet it would be nothing to do with physical systems.

14) The population of Britain in 1086 is estimated to have been about 1.5 million, rising to about 7 million pre-plague in the 14th Century. It's now 66 million. In other words, without an organized economy, it would be very difficult to see how we could feed such a population.

15) Therefore, with simply a collapse in the present organization of the financial system, economy and governance systems, it is not impossible that a large proportion of the human population would starve.

16) Previously if regimes collapsed etc, it wasn't a big thing when most people were peasant farmers and we had small self-reliant local economies. But with a massive population reliant on long supply chains and industrial agriculture it is very different.

17) What I am getting here is this is the problem of trying to predict the impact of the climate and ecological crisis on the human population and it's ability to feed itself, because you have this wild card of up to what point would the system function as an organized economy.

18) Those modelling crop yields with regard to climate impacts, are wrongly presuming the present organized economy, will remain stable and intact. This is not a safe assumption.
independent.co.uk/climate-change…

19) This is why it is almost impossible to model the impacts of the climate crisis on our modern society, because most conventional models unrealistically assume the ongoing stability of an organized economy and governance system.
independent.co.uk/climate-change…

20) This is why Ben's "most people dead at 4C" might not be as unrealistic as it sounds. But it is impossible to predict or model when this societal and economic collapse may happen, or what course or form it will take.

21) It's all very well for @ClimateofGavin to say where is the evidence, where is the study, the paper? But no one can realistically model either when such a collapse of the complex organized economy will happen or what course it will take. Even though it is quite possible.

22) All we can say for certain is that the more adverse the situation is, the more likely it is that our present civilization will undergo some sort of collapse, as have previous civilizations. Historical precedent demonstrates that these civilizations don't quickly recover.

23) What is more, I haven't even got onto the matter of ecosystems, how they sustain our society/economy, and how difficult it is to model them, let alone how this would interact with our organized economy/society.

24) So yes, Ben is going out on a bit of a limb, because there are so many unknowns. But these estimations are not unrealistic. What is more those like Gavin are just looking at physical parameters, not the complex organizational nature of human society and ecosystems.

25) The irony is that Gavin is scathingly dismissing what Ben says because he is saying there is no certainty for such claims. Yet there is even less certainty for asserting that Ben is wrong.

@threadreaderapp please unroll?