Thread by @CColose

Since I’m meant to be a member of the cult shushing everyone about Tonga, I’d like to talk about it. There was a time in ancient history (Before Covid) when I PhD'd on volcanic stuff, then I wanted to blow up GCMs even more with exoplanet modeling. So we're wiping the dust off.🧵

https://twitter.com/RogerPielkeJr/status/1688998443807805442

Tonga was first detected by geostationary satellites on January 15, 2022. Rather than silencing it, there was some initial fascination about the intensity, record-setting altitude, and global extent of atmospheric waves emanating from the source. And of course a lot of interest… twitter.com/i/web/status/1…

This was a region well monitored by satellites. In fact, Tonga didn’t just reach into the stratosphere, but even the lower mesosphere, higher than Pinatubo. This allowed things to circumnavigate the planet in only ~1 week

https://t.co/MdncQs0Todscience.org/doi/full/10.11…
agupubs.onlinelibrary.wiley.com/doi/pdf/10.102…

Unlike other big eruptions like Pinatubo & El Chichon, the caldera was 150 m below sea level, so a lot of seawater available for magma interaction & very high water vapor amounts entering the atmosphere. The injected stratospheric H2O was ∼10% of the entire background amount.… https://t.co/iJMQVSjsPvtwitter.com/i/web/status/1…

The injected amount of H2O was unprecedented in the monitored era, with the perturbation months after the eruption being strongest in the southern tropics and 20-30 km altitude. Pinatubo H2O was much smaller.
https://t.co/WZEWNAtqqbnature.com/articles/s4324…

A lot of previous volcanic eruptions *cool* the planet through SO2 release that converts into sulfate aerosol and reflects sunlight. Tonga was low in SO2, likely due to very rapid conversion of SO2 in the water-rich eruption plume (see … https://t.co/iXXmPbgCiYnature.com/articles/ngeo2…
twitter.com/i/web/status/1…

The radiative effects were studied early because of how unusual this eruption was, in contrast to the idea that scientists really want to keep this quiet.
https://t.co/AiMpEo0147nature.com/articles/s4324…

Tonga has come up recently because of the unprecedented July 2023 temperatures. But estimates of the radiative forcing of the ~1-2ppm stratospheric H2O anomaly are on the order of ~0.12-0.15 W/m2, somewhat small even in the February following the eruption … https://t.co/0no5jLHMhH https://t.co/17K2ube8a2agupubs.onlinelibrary.wiley.com/doi/10.1029/20…
twitter.com/i/web/status/1…

The estimated temperature response to this is ~0.04 C, see . This is much smaller than the effects of climate change (relative to even decades ago) or El Nino (relative to a few months ago). https://t.co/aeL1RRAKOGnature.com/articles/s4155…

It's worth noting that there's a long history of radiative forcing calculations in climate science, and perturbations to stratospheric water vapor, that act to cool the stratosphere and warm the troposphere, is part of that scholarship. See e.g., Oinas et al. 2001… twitter.com/i/web/status/1…

In a study of historical strat. water vapor changes, Solomon et al. report their forcing for a uniform 1 ppm H2O increase above the tropopause(~0.24 W/m2), which is a comparable number to the actual Tonga perturbation, and a value not too different from the estimates more… twitter.com/i/web/status/1…

The point is, we have the bedrock for thinking about planetary radiative perturbations; these things have been thought about even w/o natural experiments like Tonga that are out-of-sample. Just as Pinatubo was modeled & the cooling was predicted. pubs.giss.nasa.gov/abs/ha00800v.h…

This explanatory and predictive power is a triumph of climate science going back to the 1960s, and has proven to be successfully applied across a large domain of climate change problems and far superior to any alternative model the skeptic-sphere has generated.