The CBC is at it again, this time with Parts of South Asia could be too hot to live in by end of century. It makes some very frightening claims. I’m going to examine their claims in the light of yesterdays article, which I commented on here: Economists Think They are Climatologists.
MIT professor Elfatih Eltahir says the business-as-usual model is the “most likely scenario” and an example of the dire direction the world is headed, especially in South Asia.
The business as usual model is the IPCC’s RCP8.5 scenario. Yesterday’s article quoted a study that used economic models to predict that there was a 90% chance that the actual emissions would match either the RCP4.5 or RCP6.0 scenarios. This means there’s only a 5% chance each for either the best case RCP2.6 or the RCP8.5 business as usual scenario. Claiming RCP8.5 is the “most likely scenario” is irresponsible.
About 15 per cent of the South Asian population gets exposed to [wet bulb] temperatures of 31 or 32°C, but under the business-as-usual model that number would reach 75 per cent by 2100, the study found. Four per cent of that population would see wet bulb temperatures of 35°C [the level fatal to humans].
Is that based on an increase of 2.6°C (the low end of the estimate in the worst case scenario), 4.8°C (the high end in the worst case scenario) or somewhere in between?
Under the moderate mitigation model, 55 per cent of the South Asian population, which also includes Afghanistan, Bangladesh, and Sri Lanka, would be exposed to wet bulb temperatures of 31 or 32 C.
What is the “moderate mitigation model”? Is it RPC6.0? If so, what is the impact if we achieve the reductions needed to fall into the RPC4.5 scenario, which is in line with the targets of the Paris Climate Agreement?
“(This research shows) the kind of things that could happen if we keep going in this trajectory of no action related to climate change or minimal action.”
But we aren’t doing that. Even the American’s, despite Trump’s pulling them out of the Paris agreement, are heading down the path of electrification and conversion from coal to natural gas. One of Trump’s (valid) criticisms of the Paris agreement is that India and China have made no commitments to reducing or curtailing emissions. India wants everyone else to change our trajectory, but isn’t willing to do so herself.