Climate change as the paramount issue

I may have mentioned before that I participate in a local study group on sustainability which has now been running for slightly less than a year. We discuss many aspects of sustainability but so far we have tended to focus on social and economic issues. Although the issue of climate change has always been there in our minds, we have tended not to focus on it. This, I think, is because none of our early participants has a significant scientific education and so other aspects of sustainability have seemed more accessible.

I think we have to tackle the subject nevertheless. This is because I think the threat from climate change requires us to overturn a lot of generally-accepted thinking about the economy and this has profound political and social implications. Furthermore, other perceived threats to our civilisation -  such as food shortages resulting from over-population - would look manageable were they not amplified either by the effects of climate change or by action needed to tackle it. Before I elaborate, I should clarify some of my premises:-

1. We are currently heading for four, five or even six degrees celsius of global warming by 2100 - ie within the lifetime of many people born recently. Timely action worldwide (of which there is little sign at present) might enable us to limit the rise to two or three degrees.
2. Four or more degrees of warming probably means that much of the world will no longer be habitable or fertile and therefore it implies a major and abrupt reduction of the world population - hence a generation of people for many or most of whom life would be rendered nasty, brutish and short by starvation, war and disorder.
3. Even two degrees of warming by 2100 may not bring us to an equilibrium temperature. It may go on rising for several more centuries as a result of positive feedbacks, such as more water vapour held in a warmer atmosphere, forest die-back, methane from melting permafrost and sea-bed clathrates. These would be countered by a negative feedback - increased outward radiation resulting from a higher surface temperature  - but the final equilibrium temperature may be higher than would allow much terrestrial life to carry on outside the polar regions.
4. We have left it too late to take effective action against global warming that does not involve some radical changes to our way of life.

These premises are rather vague and I haven't attempted to assign probabilities to them. It may be that, for reasons presently unknown or not accepted among mainstream climate scientists, we will get away with a benign equilibrium temperature - even if we burn our way through all the remaining accessible fossil fuels. However my limited, lay person's knowledge of the climate science suggests that catastrophe is at least as probable as a benign outcome unless very much more determined action is taken to curb greenhouse gas emissions. If our grandchildren and great-grandchildren live in a benign climate it may be more through good luck than through precautionary action on our part.

Not everyone will agree with my premises. I am open to persuasion that a climate catastrophe is highly improbable - but I need evidence. In the meantime, I see a moral imperative to act decisively to curb our greenhouse gas emissions.

Here are some examples of what I think are the implications:-

1. Economic policy currently tends to aim at economic growth. Climate change threatens to bring about future economic collapse (along with population collapse and civilisation collapse). Tackling climate change may not be consistent with continued economic growth - we might need a long "managed recession" in order to tackle it effectively.
2. The threat of economic collapse resulting from climate change means that economic efficiency as defined, say, in terms of value added per unit of labour, is no longer a paramount consideration. Social and economic resilience become more important.    
3. Public policy will need to have sustainability as an overriding aim. This will mean more government intervention in the economy, which may look more like a war economy (which has an overriding aim of winning the war) than what we think of as a peacetime economy. So, for instance, as climate change threatens devastation of food production in many parts of the world, governments will need to ensure that their countries are highly self-sufficient in food, even when it would be more economically efficient to rely heavily on food imports.
4. A steady-state or receding economy will put great strains on political and financial systems which will no longer be able to meet pension and other commitments from the proceeds of economic growth. However, this may be less of a problem if the threats from global warming are well understood by people generally.  
5. Free markets and globalisation may promote economic efficiency but not necessarily economic resilience. Public interventions will be necessary to promote resilience.
6. If climate change were not such a major threat, problems such as resource depletion might be tractable through the normal workings of the market. As key minerals became more scarce, the price of them would rise and this would result in more sparing use and progress in finding substitutes. This would apply to fossil fuels; as coal, oil and natural gas became more expensive, the market would bring about higher investment in renewable energy and energy conservation. Unfortunately, the threat of climate change means that we will need to reduce our burning of fossil fuels long before depletion and the market force us to do so. In this area, market forces would work against a desire to tackle the threat of climate change. Hence a need for robust intervention by public authorities.
7. The challenge of feeding nine billion people may still be tractable in 2050 when the devastating effects of climate change may still lie in the future. By 2100, on the other hand, we may be living in a world that can only support, say, five billion.

So there we have a few reasons why I think climate change is the paramount issue when I consider sustainability or of the future generally.