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…

I’ve seen a lot of confusion recently about some concepts in climate related to sensitivity, feedbacks, “tipping points,” runaway warming, & how that relates to emission choices humans make in the future. This 🧵 is to help. I’ll start simple then get more technical. Feedbacks & climate sensitivity are anchored to relationships between the energy balance of the planet & its temperature. Feedbacks affect the manner that temperature needs to change to achieve radiative equilibrium (when the energy absorbed from the Sun = what it emits).

Since it's in the news, how does ENSO affect global temperature? Take a global-scale temperature product like GISTEMP, remove the trend, and sort by El Nino, La Nina, or “neutral” periods, accounting for different lag times at each point. You get something like this. During El Nino, there is buildup of heat in the ocean that spreads eastward across the Pacific and poleward along the two Americas. The tropics and (global-mean) warm, with slight cooling in parts of the higher latitudes. This pattern is ~opposite during La Nina.

There’s been interesting discussion about this thread. I voted “no,” but I wanted to offer thoughts (more technical later in thread). I’ll be jumping around the range of plausible and implausible human-relevant climate changes.

https://twitter.com/Peters_Glen/status/1435488027812548611

First, I don’t think the term “runaway” should ever really be used except in some very specific cases. For example, a snowball earth (cold) or runaway greenhouse (hot) transition are “runaways,” that stabilize in a drastically different climate.

While #Mars2020 #CountdownToMars retains a big news and #scicomm presence, I wanted to offer this tangential thread on some of the current science around ancient Mars and habitability studies. Gear up! Today Mars is lifeless with an ultra-thin atmosphere (even if you could get over the cold and lack of oxygen, your organs would rupture, outgas, and cause a rapid death). But it also leaves behind an imprint of fascinating geology from a potentially habitable past.

Thread on Venus—a bit on phosphine detection, but for broader context

Venus is a very hot (~900 Fahrenheit) planet with a thick atmosphere (~90 x the pressure on Earth, like being a kilometer deep into the ocean).

But it may have been the first habitable planet. The starting point for habitability discussions—be it on ancient Mars or distant exoplanets— is usually having a climate in which liquid water is stable in the liquid form at the surface. That doesn’t need to be the only starting point, but it is compelled by Earth requirements.

This is a terrible article. There are some errors, but the main issue is to take the wildest claims from activists that never came from the clim sci community, and in fact have been called out ("12 years", "Amazon is lungs of planet"), and apologize that the activists were wrong.

https://twitter.com/ShellenbergerMD/status/1277380835532877824

Naturally, the nonsense that came out of the activists are not "the IPCC." This has been robust across multiple assessment reports.

Thread time (mildly technical) for some broader context in relation to #PolarVortex

Because it’s popular, let’s dig in, and also is this thing related to global warming? Let’s start with the basics. We’ll get to polar vortex toward the end. It turns out when you take a “fluid,” like an atmosphere, or a big water tank in a lab, and subject it to temperature gradients (e.g., driven by differential solar heating) and then make the fluid rotate, interesting things happen.

Intro to seasons:

The Earth is tilted bigly. Venus wishes it had our tilt. Lying Venus says it has a tilt of 180 degrees. They just say that because it spins backwards. Lying Venus. Venus doesn't have the guts to have seasons! I watched her on FOX news and agree she is hell.

https://twitter.com/realDonaldTrump/status/1090074254010404864

Then in the summer we tilt and get more sunshine. A LOT MORE. I know all about sunshine, believe me, you wouldn't believe the amount of sunshine we get.

After a week of cool science at AGU, these give me headaches, but here's a short history of Venus.

https://twitter.com/JunkScience/status/1073757414770524162

Once upon a time, there was a planet, pretty comparable to Earth in size. It could of had a nice climate for a bit...depending on things like topography and rotation rate. A slow spin exposes its dayside to the sun for almost two months at a time, which sounds bad but...

Because it’s in the news, this is a thread on #HothouseEarth.
@bobkopp has one too

https://twitter.com/bobkopp/status/1026782504844517383

But I want to say some other things. First bit a summary, then my thoughts. This cartoon in their paper is an anchor point for the thread, which the authors (Steffen et al.) present to frame their discussion of climate stability and tipping points

Mini thread on climate without the Sun!!

So the other day I started a GCM run, and because I was silly, I effectively zeroed out the solar constant by accident. So I can turn a scrap run into a learning experience! What would the climate do if the Sun went black today?

The model has made it a few decades without crashing (which it will at some point), but here is a plot of some results.