So, Why 1250?

The 1250 rationale


We strongly agree with Bill McKibben that atmospheric CO2 needs to be brought down to 350ppm, if not lower. But the library above should convince you that this CO2 goal is by no means enough now. Indeed, we at 1250 feel that our near-term goal is necessary to stave off catastrophe and thereby help to make the 350 goal realistic later. And fundamental to the rationale of 1250 is that, unlike the 350 target for CO2, the needed emissions cuts for this methane target, as well as those other measures in 1250’s package of near-term climate rescue, might, with a global-scale effort, be achievable in little more than a decade, and then the atmospheric adjustment to a concentration of 1250 would be reached in about two decades.

The 1250 methane target is capable of mitigating warming far sooner than CO2 emissions reductions could. These methane reductions, of course, are not instead of CO2 reductions – they are in addition to them.

The 350 movement is based on a paper of James Hansen (Target Atmospheric CO2: Where Should Humanity Aim?, Hansen et al, 2008), and the 1250 concept is as well. So let’s go over some key points with supporting quotes from Hansen which further strengthen the case for 1250:

• Lower non-CO2 levels could help the climate system remain relatively stable in the face of elevated CO2 levels.


special effort to reduce non-CO2 GHGs could alleviate the CO2 requirement, allowing 25-50ppm more CO2 for the same climate effect.

• It is in any case actually better to deal with the different GHGs separately, and not in a “comprehensive” program that translates the values of these different elements poorly.


It would be better if all climate forcings were not packaged together and made interchangeable with CO2 in mitigation strategies. Sources of different gases are usually independent and greater progress is likely from complementary focused programmes.

• Without 1250, 350 might become impossible.


There seems to be a dichotomy of possible futures: either achieve strong reductions of both CO2 and CH4 emissions or both gases are likely to increase substantially.

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1250 Basics Slideshow

1250's '101', introducing core concepts.

This slideshow goes over the basic arguments, and puts forth the grounds for supporting the 1250 approach.

We fully agree with James Hansen on all his points above, and believe that it makes little sense not to be acting on methane and other non-CO2 reductions ambitiously right away, especially in light of the political gridlock surrounding the much more challenging problem of cutting CO2 emissions

Indeed, one primary problem today is that no governing body is nearly ambitious enough in its goals for these non-CO2 climate factors, although they will play a key role in the future path of climate change – indeed, from now through the middle of this century, they will play a dominant role.

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