: The first result we found is that all of the 17 models correctly projected global warming (as opposed to either no warming or even cooling). While this is so unsurprising to climate scientists that it is not even mentioned in the paper, it may be surprising to non-experts. The second result is that most of the model projections (10 out of 17) published between 1970 and 2000 produced global average surface warming projections that were quantitatively consistent with the observed warming rate.
: While comparing global warming rates may seem like a straight-forward “apples to apples” comparison, it sweeps one very important difference between the simulated climate projections and reality under the rug: human behavior. Climate modelers have to guess at plausible future scenarios of anthropogenic carbon dioxide emissions to feed into the model. Some modelers developed projections meant to be realistic predictions of what society would actually do (e.g. Nordhaus’ 1977 coupled climate-economic model), while others chose to estimate “worst-case” (high emissions) and “best-case” (low emissions) scenarios to bracket all plausible realities.
: When conducting our comparison, given this information, it became clear to us that simply comparing the warming rates between simulations and reality could be misleading, if the simulated emissions scenario and historical emissions were dramatically different. To account for differences in emissions between the simulations and reality, we calculated the warming rates with respect to anthropogenic radiative forcing, the rate at which human emissions trap energy at Earth’s surface, instead of calculating them with respect to time. Using this novel metric of the warming rate, we found that the model projections were even more consistent with reality (14 out of 17 models captured this).
> 2. Proposed economic responses to climate change do less harm than good.
As for 2, how much harm is being caused by more efficient autos, wind turbines and solar power, and battery storage? By feeding cattle a bit of seaweed?
notpachet|2 years ago
anonymouskimmer|2 years ago
> 1. Those models have increased accuracy.
GP, I've got your 1.
https://eapsweb.mit.edu/news/2019/historical-climate-models-...
: The first result we found is that all of the 17 models correctly projected global warming (as opposed to either no warming or even cooling). While this is so unsurprising to climate scientists that it is not even mentioned in the paper, it may be surprising to non-experts. The second result is that most of the model projections (10 out of 17) published between 1970 and 2000 produced global average surface warming projections that were quantitatively consistent with the observed warming rate.
: While comparing global warming rates may seem like a straight-forward “apples to apples” comparison, it sweeps one very important difference between the simulated climate projections and reality under the rug: human behavior. Climate modelers have to guess at plausible future scenarios of anthropogenic carbon dioxide emissions to feed into the model. Some modelers developed projections meant to be realistic predictions of what society would actually do (e.g. Nordhaus’ 1977 coupled climate-economic model), while others chose to estimate “worst-case” (high emissions) and “best-case” (low emissions) scenarios to bracket all plausible realities.
: When conducting our comparison, given this information, it became clear to us that simply comparing the warming rates between simulations and reality could be misleading, if the simulated emissions scenario and historical emissions were dramatically different. To account for differences in emissions between the simulations and reality, we calculated the warming rates with respect to anthropogenic radiative forcing, the rate at which human emissions trap energy at Earth’s surface, instead of calculating them with respect to time. Using this novel metric of the warming rate, we found that the model projections were even more consistent with reality (14 out of 17 models captured this).
> 2. Proposed economic responses to climate change do less harm than good.
As for 2, how much harm is being caused by more efficient autos, wind turbines and solar power, and battery storage? By feeding cattle a bit of seaweed?