Climate Endgame: Exploring catastrophic climatechange scenarios

https://www.pnas.org/doi/epdf/10.1073/pnas.2108146119

by kitkat_new • 4 years ago

44 24 4 years ago

fortytwo79• 4 years ago

Okay, now someone needs to do the same study with innocuous end game scenarios. (I know this study links to one other paper that makes this case, but I can't access it, and the abstract has a biased tone)

If you're going to explore worst-case, so you can think through preparedness, then you should also consider the trivial case to make sure we aren't over-responsive either.

SantalBlush2• 4 years ago

It will be tough to get buy-in on that proposition, because many people view this as a Pascal's-wager scenario, with belief in catastrophe being the rational wager.

labster2• 4 years ago

And then there are people who don’t think the mass extinction and mass immigration that have already happened are a catastrophe.

kitkat_new• 4 years ago

As noted by the Intergovernmental Panel on Climate Change (IPCC), there have been few quantitative estimates of global aggregate impacts from warming of 3°Cor above (1). Text mining of IPCC reports similarly found that coverage of temperature rises of 3°C or higher is underrepresented relative to their likelihood (2). Text-mining analysis also suggests that over time the coverage of IPCC reports has shifted towards temperature rise of 2°C and below https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/202.... Research has focused on the impacts of1.5°Cand2°C, and studies of how climate impacts could cascade or trigger larger crises are sparse.

Uehreka• 4 years ago

We have a ton of evidence that the catastrophic outcomes are more likely than the innocuous outcomes, so “equally weighting” their likelihood and commissioning research on that basis seems misguided.

joe_the_user• 4 years ago

The thing to study besides worst base scenarios isn't "best case scenarios" but average case scenarios. And average case scenarios look so bad that it's obvious we are massively under-responsive to this. The "best" people have done in thirty years is reduce the increase in the rate at which CO2 in being released.

photochemsyn2• 4 years ago

Realistically it would take a supervolcano or major asteroid impact to achieve such low-end radiative forcing scenarios, by injecting large volumes of material into the stratosphere and reflecting incoming sunlight, but any such event would be truly immediately catastrophic to human civilization (for example some major Yellowstone eruptions blanketed something like a quarter of continental North America with a meter of ash, IIRC), and would cause major crop failures and global starvation on an unimaginable scale. That would be worse for human civilization than any projected warming over the next century. Also, once the dust eventually cleared, the atmospheric CO2 levels wouldn't have changed much, so warming would continue (for about 100 years until temperatures equilibrated, assuming human civilization was basically destroyed and no more fossil emissions were taking place).

Case example: the Pinatubo explosion (1991) resulted in a bit less than a decade of steady temperatures, as predicted by climate models at the time:

https://pubmed.ncbi.nlm.nih.gov/11976452/

I suppose if we had a Pinatubo every ~5 years for the next 100 years it would result in the lowest plausible warming scenario, without destroying global agriculture.

c1sc0• 4 years ago

I’m in. How can we make this happen?

photochemsyn2• 4 years ago

This article by some of the same authors in this one is perhaps more accessible:

(2019) "Climate tipping points — too risky to bet against"

https://www.nature.com/articles/d41586-019-03595-0

"The palaeo-record shows global tipping, such as the entry into ice-age cycles 2.6 million years ago and their switch in amplitude and frequency around one million years ago, which models are only just capable of simulating... Now we are strongly forcing the system, with atmospheric CO2 concentration and global temperature increasing at rates that are an order of magnitude higher than those during the most recent deglaciation."

The central issue for human civilization is just how fast these changes are going to happen. Currently it takes about ten years for the warming signal to overrule the natural variability, for example a running 5-year average shows clear warming if you center each average ten years apart, i.e. 2008-2012 is clearly warmer than 1998-2002 and so on. Can humans adapt to this rate of warming over the next 100 years without enduring some degree of civilizational collapse, population reduction, etc.? Who knows. That's what's in the pipeline though, no longer any doubt about it. The real uncertainties are whether there might be any radical spikes in extreme weather or warming rates along this trajectory.

"Atmospheric CO2 is already at levels last seen around four million years ago, in the Pliocene epoch. It is rapidly heading towards levels last seen some 50 million years ago — in the Eocene — when temperatures were up to 14 °C higher than they were in pre-industrial times. It is challenging for climate models to simulate such past ‘hothouse’ Earth states."

The rational thing to do, given our current state of knowledge, would be to institute a crash program to replace 3% of global fossil fuel use per year with a similar production of renewable energy capacity per year, which would require global coordinated industrial production at a truly massive scale, but humans are not rational actors, as economists have demonstrated.

POPOSYS• 4 years ago

Interesting last paragraph "Updates & Corrections" in the Nature article:

"Correction - The figure ‘Too close for comfort’ in this Comment incorrectly synthesized and interpreted information from the IPCC. The graph labelled the temperatures as absolute, rather than rises; misrepresented the levels of risk; misinterpreted information as coming from a 2007 IPCC report; extrapolated the focus of a 2018 report; and was not clear about the specific sources of the information. The graphic has been extensively modified online to correct these errors."

This is a top level publication, an article by the leading scientists in the field of climate change. It is so frustrating to see these errors happening on that level. One such little error generates more damage than 100 fake reports produced by the oil industry. Very sad.

xnx• 4 years ago

Dupe: https://news.ycombinator.com/item?id=32323757

evelynsalt• 4 years ago

Peak energy deserves more discussion. The world uses 150 petawatt-hours which will be 300 petawatt-hours in 45 years.

No matter what we do, what energy source we use, we cannot meet these exorbitant demands for energy.

e.g. you'd have to build 1031 nuclear reactors per year for 45 years starting today to generate 300 petawatt-hours.

cityofdelusion• 4 years ago

The worlds energy supply has doubled in the past 50 years. Another doubling seems easy, especially with wind/solar prices plummeting every year.

cplusplusfellow• 4 years ago

There is a limit to my faith that the plummeting of these prices will continue without fossil fuel use to produce the equipment. We are also in an inflationary period where raw materials may see outsized gains.

Build the nuclear plants.

sofixa2• 4 years ago

especially with wind/solar prices plummeting every year.

Past performance isn't indicative of future gains. At some moment prices will plateau, or even rebound (e.g. the same was said for batteries, and now prices are up due to too much demand and raw material shortages).

Not to mention that at some point you will run out of suitable locations either due to actual space limitations or just lack of desire from people to have wind turbines nearby or solar panels taking up valuable land. (Of course offshore wind and rooftop solar kind of mitigate this).

You can't really beat the energy density of nuclear reactors per land taken, so they shouldn't be discarded.

sofixa2• 4 years ago

No matter what we do, what energy source we use, we cannot meet these exorbitant demands for energy

Not only can we probably do meet them (nuclear, renewables), but we have to. Energy demands today are what they are with significant amounts of the world's population living in poverty and/or pretty poor conditions compared to what developed countries are used to. It's extremely unfair to deny those people the opportunities, not to mention that few in the developed countries would want to scale back and limit their lifestyle to the extent that it would matter. That doesn't mean no such avenues needs to be explored (e.g. LEDs, optimising transit networks, etc.) but that shouldn't be the main focus.

snapplebobapple• 4 years ago

People that think this fail to comprehend how utterly restricted the nuclear industry has been by bad regulation. We are not capturing any of the gains from scale or mass production in nuclear, we are not doing the work beyond the basic science to exploit alternate nuclear chemistries to expand usable fuel sources (there is enough fission energy in just the easily minable thorium to last thousands of years for example) and efficiently recycle partially spent fuel to maximize energy output and minimize actual nuclear waste. Even with the current nonsense in place doing what you describe is doable. Getting the regulators to use more reasonable regulation and doing the engineering to expand fuel capability and hitting 300 petawatt-hours will be very, very easy.

mikewarot2• 4 years ago

High deviance opinion to follow. I hope I'm very, very wrong about this. I've just ingested a large dose of Peter Zeihan's work, so I may be de-ranged.

Russian gas infrastructure has a high chance of collapse within the next 12 months.

China has a high chance of societal collapse within the next 60 months

It is likely 500,000,000+ people will see food scarcity before then end of 2022.

Go back and read the prediction threads here from December 2019 about the oncoming 2020 decade. There's NO hint of the pandemic.

emmelaich• 4 years ago

The possibility had been predicted by many over the last decades at least.

By its nature however, mere predictions don't get a whole lot of news.

This bet is from 2017: “A bioterror or bioerror will lead to one million casualties in a single event within a six month period starting no later than Dec 31 02020.”

Discussed at https://news.ycombinator.com/item?id=25368379

Moreover, the possibility was well canvassed by those intimately connected with the sars2 outbreak, e.g. Peter Daszak.

outsidetheparty• 4 years ago

I’m not familiar with Zeihan, but those are bold claims indeed! I’m not disputing — these are weird times indeed — but can you summarize the reasoning behind those? I’m particularly curious about what is the expected cause of Chinese societal collapse in such a short timeframe; that’s not an idea I’ve encountered.

mikewarot2• 4 years ago

The reasons I've heard so far:

They've got a Covid vaccine that doesn't work, so they're trying Covid Zero as a policy. This is effecting their production, ports, etc.

They've got issues with their pork industry. They've culled more pigs than the rest of the world has total in the last few years. They're food insecure.

They have demographic problems due to the "1 child" policies of the past.

Climate Endgame: Exploring catastrophic climatechange scenarios

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