The Royal Society has just published a collection of papers exploring the likelihood, and likely impacts of the world warming by 4°C above pre-industrial average temperatures by the end of the century.
The papers are available for free browsing and download here.
They are, as you can no doubt imagine, sobering reading. Critical take-home messages are:
1) The continued rise in greenhouse gas emissions and lack of commitment of most governments to make serious and sustained reductions in emissions means that there is very little likelihood of limiting global temperature increase to 2°C above the pre-industrial average. On current trends, our children and grandchildren will be living in a world that is, at best, 3° or 4°C hotter than that (and higher temperatures can’t be ruled out).
Despite high-level statements to the contrary, there is now little to no chance of maintaining the global mean surface temperature at or below 2° C. Moreover, the impacts associated with 2° C have been revised upwards, sufﬁciently so that 2° C now more appropriately represents the threshold between ‘dangerous’ and ‘extremely dangerous’ climate change.
2) There is an enormous gap between what would seem to be any rational response to the risks involved, and the commitments made by most governments. Simply put, on current policy commitments (and these are merely pledges, not concrete action) we face a 50:50 chance of exceeding a 3.5°C temperature rise before the end of the century.
3) The longer we delay significant and sustained cuts to greenhouse gas emissions, the more likely that higher temperature rises will be unavoidable. Earlier reductions are more effective for limiting likely temperature increases than later and even more drastic cuts.
4) Adapting to a warmer world will not simply be a matter of adjusting to slightly warmer weather – drinking a bit more and staying out of the sun. There will be significant shifts in rainfall patterns, sea level rise, impacts on agricultural viability and sustainability of fresh water supply that will negatively affect and even fundamentally transform or undermine aspects of our societies and economies.
The potential severity of impacts and the behavioural, institutional, societal and economic challenges involved in coping with these impacts argue for renewed efforts to reduce emissions, using all available mechanisms, to minimize the chances of high-end climate change.
It would be great to see these renewed efforts, and all available mechanisms being put to the task, but when the politicians I elect are indifferent or hostile to meaningful action, when my own actions demonstrate my fundamental lack of concern, I wonder what answer I’Il be able to give to my children, to the world’s vulnerable poor, and to the Creator, when I’m asked, “How did you let this happen?”