And this also fits here:
Study finds we’re already committed to more global warming—sort of
Someday, humans will get it together and dramatically reduce greenhouse gas emissions. But—not to fact check your daydreams too strictly here—how exactly will global temperatures respond to that day? This is a question climate science has long worked to answer, although devils in the details have led to some confusion.
A new study led by Nanjing University’s Chen Zhou tracks down another devil and puts it on display. Research has increasingly shown that it’s not just the planet’s average surface temperature that matters for tracking warming, but the spatial pattern of those temperatures. That can be important for calculating things like the climate’s sensitivity to greenhouse gases, but it hasn’t been accounted for in some methods of estimating how emissions cuts affect warming.
Seeing a pattern
This “pattern effect” of warming in different areas of the globe influences the way the planet sheds heat back to space. For example, if warming is a little stronger in the western equatorial Pacific Ocean—which it has been—that region is better at producing sunlight-reflecting cloud cover and releasing heat upward. If you assume the warming is occurring evenly around the world, you will miss that slightly offsetting behavior.
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Calculations of the warming that we’re already committed to also depend critically on assumptions about what our future emissions will look like—a major source of confusion. The scenario used in this paper is one where we reduce emissions enough to simply maintain current greenhouse gas concentrations.
With that in mind, the results show that accounting for the pattern effect should increase committed warming. For concentrations stabilizing at 2020 levels, if we wait centuries for temperatures to equilibrate, total warming since pre-Industrial times grows from about 1.3°C to 2.3°C. (We have so far experienced about 1.1°C warming.)
An alternate version of this scenario allows short-lived gases and particulate matter to fade out; here, the ultimate warming grows from 1.6°C to 2.8°C. Restricting this very long-term view to just the year 2100, warming grows from 1.3°C to 1.8°C when accounting for the pattern effect.
The exact numbers aren’t really the point here—the researchers note that using a different dataset for past ocean temperatures causes the differences to shrink.
It's the general finding—the existence of the pattern effect implies more committed warming—that's potentially important. It could mean that if you really want to permanently limit warming to a certain goal, like 1.5°C or 2°C, you need to err on the side of even lower emissions (or plan on actively removing more CO2 later on).https://arstechnica.com/science/2021/01/study-finds-were-already-committed-to-more-global-warming-sort-of/