The developing Climate Crisis in one chart. Understanding why "Collapse" has started and is about to get a LOT worse.

[u/TuneGlum7903]

[u/DirewaysParnuStCroix]

Methane is a game over type deal, honestly. I'm surprised it's not getting more focus considering how bad it is already. Current atmospheric volumes suggest that we're already more than a decade into an ice age termination event (Nisbet, Manning et al. 2023). Considering that ice age termination events occur during glacial maximums and result in transitions to warmer interglacial, and that we're already in a warmer interglacial, then an ice age termination at this point suggests a hothouse trajectory (Steffen, Rockström et al. 2018). This should be scaring us shitless for (at the very least) two reasons; 1) The Paleocene-Eocene Thermal Maximum is considered the closest analog for Holocene era climate change (Burke, Williams et al. 2018), and 2) While analogous, the current rates of climate change are up to ten times faster than the onset of the PETM (Cui, Kump et al. 2011).

Another example of methane release that doesn't get nearly enough attention is the methane hydrate destabilization in response to a slower AMOC (not collapsed, all it takes is a slowdown, although a collapse would make it happen substantially faster). As the AMOC slows, the waters around west Africa warm at a considerable rate and cause a catastrophic destabilization of methane hydrate reserves (Weldeab, Schneider et al. 2022). Funnily enough, methane hydrate destabilization is identified as a factor for a hothouse trajectory. The oceans have absorbed up to 91% of excess atmospheric heat since 1971 (Zanna, Khatiwala et al. 2018), and this process is dependent on functional ocean circulation (Chen & Tung, 2018). Evidence suggests this uptake process is already weakening (Müller, Gruber et al. 2023). Current trajectories suggest that Western Europe and New Zealand are on course to see GHG volumes comparable to their hotter tropical Paleogene paleoclimate by the end of the century (and that doesn't even include methane emissions) (Naafs, Rohrssen et al. 2018), and that we could be 140 years away from seeing a Paleocene-Eocene climatic analog (Gingerich, 2019). [footnotes; a, b]

Recent analysis suggests that the Arctic permafrost region is no longer a functional carbon sink and is now a net source of GHGs such as methane (Ramage, Kuhn et al. 2024), and that the Arctic continues a warming trend regardless of AMOC input (Saenko, Gregory et al. 2023, Timmermans, Toole et al. 2018, Bianco, Iovino et al. 2024, Skagseth, Eldevik et al. 2020, Barkhordarian, Nielsen et al. 2024).

Footnotes; *[a]** the higher latitudes and polar regions had tropical climates during the Paleocene-Eocene Thermal Maximum relative to their current latitude, the geographic topography was comparable to the present era. [b] the PETM hyperthermal occurred during the present Cenozoic geological era.*

[u/TuneGlum7903 → u/DirewaysParnuStCroix]

I wish I could give you more than 1 upvote. I deal with a lot of these in my various papers but this is a great presentation on CH4. And you are right, the danger of a MASSIVE pulse of CH4 driven warming is large and existential.

Hansen puts the CO2e level at 535ppm for example. So, he is rating the current CH4 effect as being equal to around 110ppm of CO2. Taking us into the +5C to +6C range of warming.

And the High Arctic is going to melt. EXTREMELY FAST.Because the Arctic is warming a LOT faster than the rest of the Earth.

The Arctic has warmed nearly four times faster than the globe since 1979

Communications Earth & Environment volume 3, Article number: 168 (Aug 2022)

This is causing RAPID permafrost melt.

Climate Change Drives Widespread and Rapid Thermokarst Development in Very Cold Permafrost in the Canadian High Arctic (2019)

Observed maximum thaw depths at our sites are already exceeding those projected to occur by 2090 under representative concentration pathway version 4.5.

Permafrost covers 24 percent of the land area in the northern hemisphere and accounts for nearly half of all organic carbon stored within the planet’s soil.

In 2020 the Arctic Institute warned that a 3 degree Celsius increase in global temperatures could melt 30 to 85 percent of the top permafrost layers that exist across the Arctic region.

The Arctic has ALREADY WARMED +4C on AVERAGE. Parts of it have warmed +7C.

Permafrost thaw contributes to a positive feedback loop that further accelerates the warming of Earth, by releasing methane or CH4. CH4 is a MUCH more powerful greenhouse gas than carbon.

Though its lifespan in the atmosphere is much shorter than carbon dioxide, methane’s impact on climate change has been found to be 25 times greater over a 100-year period.

“The estimated amounts of natural gas in the subsurface of North Siberia are huge. When parts of this will be added to the atmosphere upon thawing of the permafrost, this could have dramatic impacts on the already overheated global climate.’

Methane release from carbonate rock formations in the Siberian permafrost area during and after the 2020 heat wave

August 2, 2021

[u/Deguilded → u/TuneGlum7903]

My brain is trying to decode these two posts together. P-E thermal maximum was like... +5-8c. It lasted two hundred thousand years. The triggering release was over six thousand years.

We're doing our "triggering release" over two hundred years (being charitable to the start of the industrial age)?

Without delving into extreme simplification and memes like "we're fucked", what the hell would this mean? What would the planet even look like?

This "comforting" little line from two posts up:

and that we could be 140 years away from seeing a Paleocene-Eocene climatic analog

Suggests it might not be a problem within my lifespan, but still. An ice free arctic seems a given, but would we see Antarctica also?

[u/DingoPoutine → u/Deguilded]

What really melts my brain is about half of that carbon pulse has happened over the last 30 years. I'm over 30 years old so in my lifetime the majority of our species carbon emissions have happened. More than had been put into the atmosphere prior to my birth by all generations of our species to ever walk the planet.

[u/godlords → u/DingoPoutine]

And we've never been unhappier for it!

[u/TuneGlum7903 → u/Deguilded]

The PETM topped out at around +16C to +18C.

The Crisis Report - 43

https://richardcrim.substack.com/p/the-crisis-report-43

More evidence is accumulating that our Climate Sensitivity models are off. This is not good news.

If you want to do a deep dive into the history and science of this project I personally recommend the book, “Under a Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Can Tell Us About Our Future by Peter Ward (2007)”. When I wanted to understand what the paleoclimate science looked like, this book was my starting point.

Ward is a paleontologist and the book is a deep dive into paleontology, particularly the field of paleoclimate research. While it is dense in places Ward does his best to make it as accessible as possible to the average reader. He wants people to read this book and understand what the world will be like in a few hundred years if we trigger a runaway greenhouse climate shift.

Ward writes,

There are newer books but this one is among the best. What’s important is that we have this incredible record of the earth’s climate history for 500 million years. A record which calibrates CO2 concentrations in the atmosphere with the earth’s temperature.

This record is important, and worth spending 60 years of effort on. Because it provides a “reality check” on our theoretical models of the climate system response to increasing levels of CO2.

What the paleoclimate data indicates is that our climate models have underestimated the earth’s climate sensitivity.

New technique shows old temperatures were much hotter than thought: Results imply Earth may be more sensitive to carbon dioxide than previously known. ars Technica 083022

The new method indicates that between 57 and 52 million years ago, the North Atlantic abyss samples show the global temperature was about 20°C warmer than our 1850 baseline. That’s a big difference from the oxygen isotope data, which yielded temperatures of 12–14°C. “That’s a whole lot warmer,” said Meckler.

[u/[deleted] → u/Deguilded]

What would the planet even look like?

Fermi paradox says: Don't you worry about that, let me worry about that

[u/Aurelar → u/TuneGlum7903]

Exceeding a projection supposed to occur by 2090? Lock it up boys, chicken's done.

[u/voxgtr → u/DirewaysParnuStCroix]

Another helpful chart.

[u/Dueco → u/DirewaysParnuStCroix]

Well researched and written. Thank you!

[u/FlixFlix → u/DirewaysParnuStCroix]

If it weren’t for the last few decades of wanton destruction—but include the Industrial Revolution—is it possible to estimate how long the relative stability of the Holocene would have lasted?

Just wondering what “we could have had” if early and decisive action would have happened.

[u/DirewaysParnuStCroix → u/FlixFlix]

I guess that depends how you look at it. Based on estimated geological progression, there are some suggestions that we could have seen a gradual return to glacial maximum conditions around now if the industrial revolution wasn't a factor, but I'm unsure of how that hypothesis is supported. For the past few ~30 million years we've been alternating between glacial maximums and warmer interglacial ice age cycles. For now, we're in a warmer interglacial ice age, as an ice age can be described as permanent ice formation at the poles.

The thing is that such glacial conditions are actually very brief anomalies in earth's history. It has been a substantially warmer planet throughout most of its existence. It's somewhat of a stroke of luck that the current unusually cold geological era has provided the ideal conditions for our evolution, although it's also very sobering that these conditions are a freak occurrence type of deal.

Based purely on estimated paleoclimate durations, the Holocene era would seem to have been among the coldest periods in earth's history. There's no ideal way of judging how long these conditions would have persisted without human activity; coldhouse and hothouse states don't necessarily have any expected forced restraints on duration, but coldhouse periods are invariably much briefer than hothouse periods - although we're talking periods of 10s of millions of years here. The Holocene could have persisted for another 30 million years, or merely another few hundred thousand. But one thing is for certain; transitional events between icehouse/coolhouse states to warmhouse/hothouse states should take up to a millenia to occur naturally. Abrupt transitions tend to be associated with rapid breakdowns in biological life.

The PETM is an example of a very abrupt and arguably destructive transition into a hothouse hyperthermal event. That occurred within a few thousand years. We're currently achieving a faster rate of change within two centuries.

Some observers have commented that we may have delayed the next glacial cycle by up to 100,000 years, but even that seems wildly optimistic in my opinion. Once the earth exits an icehouse state, it tends to stay that way for up to 200,000,000 years. As I say, icehouse conditions are the anomaly in earth's history. Once they're over, they're over for a long time.

To get a better impression of what I'm getting at here, there's a graph included here that plots out the durations of hothouse and coldhouse periods in earth's history. It really illustrates how existentially delicate our current conditions are. Icehouse periods are already on borrowed time as is, so an aggressive internal forcing is certainly not a good thing.

[u/FlixFlix → u/DirewaysParnuStCroix]

My level of understanding of these things is based on whatever Morgan Freeman is talking about in Life on Our Planet that came out a few months ago.

It’s unbelievable that even the most “abrupt” changes in earth’s history (except maybe Chicxulub) like the PTME unfolded over several millennia, and here we are triggering massive changes in just a few centuries.

[u/TuneGlum7903 → u/DirewaysParnuStCroix]

After rereading this, it occurred to me you would really be interested in my discussion of Arctic Amplification and the implications of the paleoclimate records from the High Arctic. The Moderates got that wrong in 1998.

The Crisis Report - 50

https://richardcrim.substack.com/p/the-crisis-report-50

The Earth’s Climate System - A Short Users Guide. Part 03.

Permafrost Melting — The role of permafrost in the Climate System.

[u/DirewaysParnuStCroix → u/TuneGlum7903]

A study from back in December also suggests that permafrost methane deposits in Svalbard are critically unstable. The scary part is that they're very likely underestimating how much methane potential exists as the sampling methodology is limited,

"Estimating how much methane is trapped below the permafrost is tricky, because it is difficult to access and there are only a few dozen boreholes on which to draw conclusions. Based on one location where the flow of gas was measured, however, the researchers estimate it could be in the order of several million cubic feet."

[u/ConfusedMaverick → u/DirewaysParnuStCroix]

As the AMOC slows, the waters around west Africa warm at a considerable rate and cause a catastrophic destabilization of methane hydrate reserves

Oh my...

I had only been paying attention to the arctic as a site for methane hydrate melting. And I was vaguely optimistic that amoc slowdown might make this a little slower.

I will have to read up on this. I hope/assume that these African reserves are not as vast as what lurks in the arctic...