Thread by @ShellenbergerMD

Most people think global carbon emissions have been rising, but new data show they actually *declined* over the last decade.

Emissions must still decline further, but temperatures are unlikely to rise above 2.5°-3°C, far less than the much-feared 6°C

carbonbrief.org/global-co2-emi…

All else being equal, we wouldn't want to change global temperatures much, since we have created cities, farms, and nature areas around current temperatures.

But all else isn't equal. Emissions are a by-product of modern energy, which reduced extreme poverty from >90% to <10%

If we had to choose, we'd rather the world got warmer than cooler, since more people die of cold than heat, and because warmer temperatures make more rather than less land available for farming, but too much heat creates new risks.

https://twitter.com/BjornLomborg/status/1418916412802965511?s=20

It is now clear that global temps will likely peak at 2.5-3C above pre-industrial levels by 2100, with a median warming 2.2C in 70% of IPCC scenarios.

Mostly this is because of far-lower anticipated coal use, thanks mostly to abundant nat gas.

osf.io/preprints/soca…

To put 2.5-3°C in perspective, Yale economist William Nordhaus, who won the Nobel Prize in 2018, calculates that the "optimum" temperature rise, when accounting for the costs & benefits of both climate change & energy use, would be between 3.5°C and 4°C

nobelprize.org/uploads/2018/1…

I am not wild about cost-benefit analyses because a lot of assumptions are buried within them. I prefer instead to think about energy & environmental progress in the context of progress from matter-dense (carbon-dense) fuels to energy-dense (hydrogen-dense) fuels.

Nonetheless, the Nordhaus cost-benefit model is helpful because it reminds us that we can't consider "how bad" certain temp increases are outside the context of considering "how good" fossil fuels have been, not just for lifting people out of poverty but also reducing wood use.

I recently noted that emissions are declining, and there is no longer a serious risk of a significant rise in temperatures.

The word "significant" was imprecise and triggered confusion, and so I revised the sentence to be more precise.

michaelshellenberger.substack.com/p/the-real-thr…

The meaning of what I wrote is the same. The news on climate change is overwhelmingly good. Human resilience to weather is higher than ever. Emissions may rise again but will peak & decline soon as we continue the transition to natural gas & nuclear

/END

environmentalprogress.org/the-case-again…