1. Two very different climate stories from yesterday – but they’re actually closely connected. Not only that: Together, they underscore a bit of a paradox in the current outlook on how bad things could ultimately get.
2. On the one hand, as @afreedma and I reported, there’s a growing argument that the worst case climate scenario used in so many modeling studies is too…worst. washingtonpost.com/weather/2020/0…
3. Specifically, you have to burn massive quantities of coal to realize that scenario (known as RCP8.5) there and it’s seriously open to question whether we will. sciencedirect.com/science/articl…
4. On the other hand, as underscored by my latest report on Thwaites glacier, West Antarctica, we’re learning that very bad things start to happen at quite low levels of warming washingtonpost.com/climate-enviro…
5. Bad things such as warm water beneath the glacier that could unlock all the ice in West Antarctica. This change is already here, at slightly over 1C of planetary warming (albeit perhaps with an added boost in this region due to our depletion of the ozone layer).
6. What does all of this mean?
7. Honestly, the answer is that there’s still reason to fear damaging levels of warming in this century, even if one particular scenario is having serious questions raised about it.
8. There’s also reason to acknowledge the argument that even the current warming may be too much. Not everywhere, perhaps. But it’s a persuasive argument for Australia these days, where you already have the devastation of coral reefs, kelp forests, and horrific fires.
9. So you don’t really need a super extreme worst case scenario in order to see that perturbing the Earth’s climate comes with severe consequences.
10. Moreover, given how sensitively the planet is already responding to the current perturbation, there’s a key point, which several people made in our story about RCP8.5, that bears emphasizing.
11. We don’t know the magnitude of the carbon feedbacks that are going to be unleashed as we continue to heat up. Maybe emissions from Arctic permafrost will be enough to take 3C of warming and drive it up another degree, and back into something like RCP8.5 territory.
12. We know there’s enough carbon in the ground to do it, but we don’t know how fast it comes out.
13. So in sum: The plausibility of RCP8.5 as an energy scenario for this century has been seriously challenged. But the potential severity of climate change really has not. /end
