[myshpa]

The warming of the oceans could lead to the following consequences:

- Coral reef collapse and loss of marine biodiversity.

- Accelerated sea-level rise, resulting in coastal flooding and displacement of populations.

- Ocean acidification, harming shell-forming organisms and marine ecosystems.

- Disruption of ocean currents, leading to altered weather patterns and increased extreme weather events, potentially causing massive oceanic dead zones leading to

- Release of hydrogen sulfide (H2S) from warming ocean sediments and decaying organic matter, a potential extinction event.

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Peter Ward: “Oceans - What’s the Worst that Can Happen?”

https://www.youtube.com/watch?v=8eM1aakTzMw

[koboll]

ME: "Release of hydrogen sulfide (H2S) from warming ocean sediments and decaying organic matter, a potential extinction event." Is this a realistic possibility?

GPT-4:

The phenomenon you're describing is associated with an event referred to as a "Canfield Ocean" or "Strangelove Ocean." The hypothesis is named after paleoceanographer Donald Canfield, who proposed that several mass extinctions in Earth's history might have been caused by an increase in hydrogen sulfide (H2S) produced by sulfate-reducing bacteria when the oceans became depleted of oxygen (anoxic).

Under certain conditions, this is a theoretical possibility. If global warming were to result in widespread anoxia (lack of oxygen) in the oceans, it could potentially trigger a large-scale release of hydrogen sulfide gas. This gas is poisonous to most forms of aerobic life (those that require oxygen), and a significant increase in its concentration could lead to mass extinctions.

However, it's essential to note that while this hypothesis is theoretically plausible, it remains highly controversial, and the conditions required to trigger such an event are extreme. It's not a certainty that global warming would lead to widespread ocean anoxia, and even if it did, it's not clear that this would necessarily result in a large-scale release of H2S.

Moreover, our understanding of the exact causes and progression of the various mass extinctions in Earth's history remains incomplete, and there's ongoing debate among scientists about the role played by hydrogen sulfide. Other factors, such as volcanic eruptions, asteroid impacts, and changes in sea level, have also been implicated in these events.

To summarize, while the scenario you're describing is theoretically possible, it's still highly speculative and there's a lot we don't know. It's not something that's likely to happen in the near future, but it underlines the importance of taking ac

[koboll]

https://en.wikipedia.org/wiki/Canfield_ocean

Also, this: https://www.smithsonianmag.com/science-nature/no-strangelove...

"Sepúlveda's team was able to tell that the carbon in these post-impact sediments could only have been assembled into these hydrocarbons (and other compounds) in a functioning open ocean ecosystem with plenty of algae photosynthesizing away at a pretty good clip. Since these sediments were deposited right after the impact, the "Strangelove" ocean theory, with a vast lifeless sea, is highly unlikely."

[myshpa]

We simply don't know. I recommend Peter Ward's video for more info.

https://en.wikipedia.org/wiki/Atlantic_meridional_overturnin...

"The impacts of the decline and potential shutdown of the AMOC could include losses in agricultural output, ecosystem changes, and the triggering of other climate tipping points."

https://en.wikipedia.org/wiki/Atlantic_meridional_overturnin...

"The possibility that the AMOC is a bistable system (which is either "on" or "off") and could collapse suddenly has been a topic of scientific discussion for a long time."

https://www.livescience.com/gulf-stream-slowing-climate-chan... (2021)

"The Gulf Stream — one of Earth's major climate-regulating ocean currents — is moving slower than it has in thousands of years, a new study suggests. Human-induced climate change is largely to blame."

"If the Gulf Stream crosses its tipping point, it will continue to weaken even if we have managed to stop global warming," Caesar told Live Science. "Afterwards, it will slow down by a lot, coming close to a complete shutdown of the circulation."

[myshpa]

Maybe controversial, but still possible.

ME: "Release of hydrogen sulfide (H2S) from warming ocean sediments and decaying organic matter, a potential extinction event." Is this a realistic possibility?

GPT-4:

Hydrogen sulfide (H2S) release from ocean sediments and decaying organic matter is indeed a plausible mechanism that could cause significant environmental changes. This process is often associated with a scenario referred to as "Canfield Oceans" or "Canfield Ocean events."

Paleontologist Peter Ward, for instance, has proposed that hydrogen sulfide emissions from stagnant oceans could have contributed to several mass extinction events in Earth's history. In such scenarios, increased oceanic warmth and decreased circulation might have led to anoxic conditions (lack of oxygen) in the deeper ocean. These anoxic conditions, in turn, would allow sulfur bacteria to thrive, which would generate hydrogen sulfide as a metabolic by-product. The hydrogen sulfide would then be released into the atmosphere, where it could cause significant environmental disruption, affecting life on both land and sea.

However, it is important to note that these scenarios are not straightforward, and various factors would need to align for such an event to occur. There are many potential feedback mechanisms in Earth's climate system that could either amplify or dampen the effects of increased hydrogen sulfide production.

In the context of contemporary climate change, we are indeed witnessing warming oceans and increases in oceanic dead zones (areas of low oxygen that can support sulfur bacteria). However, whether this could lead to an extinction-level hydrogen sulfide release is still a matter of scientific debate. Current research suggests that while an increase in anoxic conditions and dead zones is cause for concern due to their direct impact on marine life, a Canfield Ocean event is not considered a high-probability outcome of current climate change trends.

[29athrowaway]

Release of methane permafrost

https://en.wikipedia.org/wiki/Clathrate_gun_hypothesis

Not all ice is made from water. Some ice is frozen methane. If you melt it, you'll release methane.

Atmospheric methane is good a trapping heat (aka greenhouse gas). That heat warms the atmosphere, which melts more ice, which includes methane ice, which in turn releases methane, that heats the atmosphere more.

In this way you have a self-reinforcing effect where before you know it you have an exponential release of methane/exponential temperature increase and an extinction event like the Permian–Triassic one.

https://www.youtube.com/watch?v=6Z6RIQ0Bw-E