I’d been meaning to highlight a statement from Kevin Anderson for quite some time. A brief lull in postings gives me a chance to do so. It relates to the Paris goal of keeping global warming below 2oC. I haven’t double checked the numbers, but they seem reasonable and I’ve included an animation from Carbon Brief at the end of the post that nicely illustrates how difficult this is becoming.
I’ve highlighted some aspect of Kevin Anderson’s statement that I found particularly important (I transcibed it, so any errors are probably mine).
Once highly optimistic assumptions are made for curtailing deforestation, increasing afforestation and reducing process emissions from industry (primarily cement and steel), the energy-only carbon budget is highly constrained. In the absence of heroic assumptions about negative emissions (increasing the budgets) and ignoring additional positive feedbacks (reducing the budgets), OECD nations need to be fully decarbonised by 2035, with the non-OECD nations following suite in the 2050s.
Transposing this into mitigation rates (dictated by the budgets), requires OECD nations to be delivering 10% annual cuts from about ~2018 onwards. Turning to non-OECD nations, on aggregate they need to reach a peak in emissions by the early 2020s before ramping up to ~10% p.a. by the early 2040s. Add up all of this, and the collective budgets are broadly consistent with a reasonable chance of 2oC.
It is important to note that the nature of the carbon budgets mean that any failure to deliver deep mitigation rates in the near term (from a high starting value) very rapidly increases future rates to completely unattainable levels. Delay is not an option and our 2oC mitigation analysis needs to be informed by this.
We can of course throw our hands in the air and declare the implications of such emission constraints are too onerous for us high-emitters to contemplate. But then we need to be honest and say to our and others’ children, as well as many millions living in poor and climate-vulnerable communities, that we have chosen to renege on the Paris commitments. This is an authentic position, allowing others to consider the implications and make whatever contingencies they can to deal with the chaos of the 3-5oC of warming we’ve decided to bestow upon them.
Carbon brief has a recent article about carbon emissions that is relevant. It includes a figure showing how the emission pathways consistent with a 66% chance of staying below 2oC depend on the year in which emission reductions start (or could have started). An animation of that figure is in the tweet below; it’s clearly getting increasingly difficult.
— Carbon Brief (@CarbonBrief) November 18, 2017