One of the oldest denier refrains is that climate models overestimate both warming from CO2, and the economic impacts the world will endure from climate change. One of the more sophisticated (as in sophistry) denier refrains is that because we’re uncertain about the impacts of climate pollution, we should take a wait-and-see approach to climate policy.
Two new papers, covered by David Roberts at Vox, provide some reason to agree that models aren’t handling uncertainty well, and aren’t properly accounting for climate costs. What’s this? Has Roberts gone to the dark side? Have denier arguments finally been validated by real media? Is our understanding of the climate coming crashing down around us?
No.
As Roberts explains, it turns out models are likely underestimating the cost of climate change and overestimating the price tag to fight it. And a more rigorous incorporation of uncertainty actually makes climate action an even smarter decision than we already know it to be.
The first paper Roberts discusses is a Comment piece published last week in Nature Climate Change, which highlights a number of ways in which current climate models need improvement. For example: because of how models tend to rely on relatively old data for renewable cost, and because the renewable industry is beating learning curve estimates, models overestimate the cost to transition to renewables. Add in how models struggle to deal with how the transport and industrial sectors will transition to clean energy, take a relatively static view of energy efficiency efforts, and don’t fully account for many co-benefit health gains, and it’s clear that the clean energy revolution will be swifter and cheaper than models suggest.
Finally, this first paper briefly discusses the issue of uncertainty, which is the main subject of the second paper. Published in the Review of Environmental Economics and Policy, the authors argue that the IPCC’s AR6 report should take a more holistic view of uncertainty into account, because the models on which the report relies don’t accurately capture the risks and damages from potential physical tipping points.
Without getting too far into the weeds, the idea is that while certain folks make hay with the idea that maybe warming is much lower than consensus science suggests, it is more likely that warming will be much greater than the generally-accepted range. And if that 5-10% chance is realized, then it would be, per Roberts, “a 6-degree apocalypse.” Though it’s unlikely warming would be on that high end, the costs in human and economic terms would be so catastrophic that we should keep the possibility in mind when designing climate policy.
In the absence of the fossil fuel industry’s policy obstruction mechanism currently controlling our political system, these model adjustments would cause us to rethink a reasonable price on carbon. One study cited found that if tipping points were fully accounted for, the price on carbon would be $350/ton by 2100.
We hate to say it, but deniers are right that models aren’t perfect. But they’re flawed in the exact opposite way deniers allege. Turns out even when deniers are right, they’re wrong.
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