There are two ways for climate change reduction to be considered effective by EA frameworks: long-term future and saving lives/​improving utility in the presentish generation. There is some discussion here about long-term future. For saving lives, I agree it is tricky. When I attempted this in 2005, I tried to do it based on increased utility. Even though it is true that climate change will likely fall disproportionately on less-developed countries, when you look at the actual economic impacts, they accrue mostly to richer people because they make up the majority of the economy. This is especially true in the longer term, when it is likely that even current less-developed countries will be significantly richer than today. For typical cost climate interventions, I was getting they are about 2.5 orders of magnitude lower cost effectiveness than direct global poverty interventions. Another attempt is here (though you may not agree with his discounting). If Cool Earth really is significantly lower cost, of course that would improve the comparison. But I still think it is very unlikely to be better than direct global poverty interventions.
There are two ways for climate change reduction to be considered effective by EA frameworks: long-term future and saving lives/​improving utility in the presentish generation. There is some discussion here about long-term future. For saving lives, I agree it is tricky. When I attempted this in 2005, I tried to do it based on increased utility. Even though it is true that climate change will likely fall disproportionately on less-developed countries, when you look at the actual economic impacts, they accrue mostly to richer people because they make up the majority of the economy. This is especially true in the longer term, when it is likely that even current less-developed countries will be significantly richer than today. For typical cost climate interventions, I was getting they are about 2.5 orders of magnitude lower cost effectiveness than direct global poverty interventions. Another attempt is here (though you may not agree with his discounting). If Cool Earth really is significantly lower cost, of course that would improve the comparison. But I still think it is very unlikely to be better than direct global poverty interventions.