Pessimism is a dirty word in climate policy circles. There are good reasons for this, not least that optimism can spur positive change, while assuming the worst can paralyse us into inaction. But when it comes to climate modelling, some negative thinking could be a good thing., or pathways, that assess how we might limit warming to 1.5°C, or see carbon emissions continue unabated, or experience many possibilities in between.
One key assumption in scenarios that keep us below 1.5°C of warming is that, in the near future, we will rapidly perfect technologies that remove carbon dioxide from the atmosphere. This isn’t an unreasonable prediction, given human ingenuity and the strong incentives for doing so.
Such revisions in our understanding of climate change are both entirely expected and to be welcomed, but they show that the challenges facing us in the next decade have just got harder. Instead of squeezing climate models until the numbers just about fit the 1.5°C target, perhaps a more pessimistic outlook would better accelerate efforts to limit the damage.