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Without big feedback loops you actually have to go out of your way to get above a certain level of warming. RCP8.5, for 8.5C of warming, involves a frankly sill
by Brakenshire 7y ago
Without big feedback loops you actually have to go out of your way to get above a certain level of warming. RCP8.5, for 8.5C of warming, involves a frankly silly quantity of emissions, I assume this is because CO2 absorbs at certain wavelengths and there are diminishing returns as concentrations get really high.
Of course, we don’t know what the feedback loops are, they could kick in and take over. The IPCC is quite conservative about including feedback loops, and mainly deals with direct effects. But the same logic applies either way, within any reasonable range any reduction in CO2 emissions is worth pursuing.
I also personally think the economics for certain low carbon technologies will dominate over a middle/long time period, just that as it stands they won’t take over quick enough to dramatically bring down emissions.
- hire_charts 7y agoWhat kinds of feedback loops is the IPCC known to exclude, and is there any serious study into what the potential consequences are? Like, how possible is it that there is a feedback loop that will push us well beyond the RCP8.5 scenario?
- Brakenshire 7y agoTwo examples I recall are the albedo changes from melting of on-land glaciers and ice-sheets, the IPCC thinks think will take hundreds of years. And then the Methane Clathrate idea, which is very controversial but could contribute to some degree. I don’t think anyone in the world can answer the question about how likely these feedback effects are, unfortunately!