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Comment by hedora | Hacker News Reader

Tl;dr: Climate change is likely to shut down the Atlantic currents, covering Europe and the US northeast in a glacier.

(I saw a PBS special on this part in the 90's. Recent satellite data strongly suggest this is already happening. The last time this happened, Europe went from "too hot" to "glacier" in the under fifty years.

If we wait for that to happen, then cool the atmosphere, then it'll make the coming ice age worse in the short term.

In other decades-old news, if we don't start capturing CO2 after that, and the predictions about runaway greenhouse gas mechanisms are true, Earth will become like Venus, obliterating life on earth.

Am I the only one that learned about this from watching PBS in the 90s? Is there something novel in the paper? It's good to raise awareness of just how f-cked we are, I guess.

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So you feel confident that Europe will be under a glacier in 50 years?

I'm confident we'll get about 50 years warning when/if the current stops. It's currently weakening, and weather is a chaotic system.

I'm also confident that the root cause of the crunching noise and vibrations from the front end of my car will eventually lead to a breakdown, but I don't have any idea if it'll happen tomorrow or in a year.

I see. Of course the North Atlantic current will change/stop at some point regardless of any actions we take (assuming we don’t have technology to keep it going somehow). But delaying that as long as possible is a noble goal.

There's no reason to think it would shutdown in the absence of human intervention. It's extremely stable. Last time it shut down, it was due to elevated CO2 and temperatures, and the conditions that led to that won't naturally reoccur any time soon.

I think you've misunderstood the claim - they're saying that once the currents shut down, it would take 50 years for glaciers to form. But the currents are obviously still flowing today, and my understanding is that a collapse is projected to take many decades.

I get the impression they don't have any way to model the rate at which the currents will shut down, but that it was apparently quickly in the past.

Either way, we're talking about either abandoning most of Europe in our (or our children's) lifetimes, or just using existing technologies to avoid that, along with many other disasters.

Glaciers increase albedo. I suspect there are numerous understated/undiscovered feedback mechanisms which will actually result in cooling as the climate changes and keep the global temperature livable.

Not a feedback, but a reduction in polar soot due to China moving away from dirty coal emissions to nuclear power could also increase albedo.

All that freed, formerly captured carbon comes from trees and plankton. How could burning it all lead to life-destroying conditions when life must have been able to exist under those conditions?

You are releasing 1e6 to 1e7 years of energy in the space of 1e2.

Things could get very bad, but it also turns out that plankton and plate tectonics have locked carbon/energy far away from our reach. It's a very slight glimmer of hope.

Every night temperatures drop much more than the temperature increases from the hydrocarbon consumption. Are you sure that the energy of the hydrocarbons is the problem and not the greenhouse effect?

Same reason breaching a big dam does more damage than the same volume of water in an undammed river.

"all that kenetic energy released when jumping off a building was formerly potential energy stored when walking up the stairs. How can that lead to life destroying conditions when life previously held that energy?"

The rapid change in environments can make many species no longer suitable for their environment leading to extinction. Sometimes they can transfer to a new environment, or sustain at a degraded efficiency, but often they cannot if the environment change is drastic enough. This is happening everywhere all at once.

The GP isn't talking about species extinction.

Energy on Earth isn't conserved, as it's not an isolated system - the Sun is constantly adding energy to the Earth, and we are constantly radiating energy out into space as well. Coal and oil were basically batteries filled with solar energy from millions of years ago. We are now discharging those batteries, adding back all of the solar energy captured over millions of years to the Earth today, in addition to all of the energy the Sun is still adding at more or less the same rate.

It's the same principle as what makes a battery fire so destructive - all of the energy stored in the battery in a plant somewhere else suddenly gets discharged all at once in your car.

People aren’t going to destroy all life on earth via climate change because humans are going to be dead in conditions that many life forms would happily survive in. Having said that, evolution operates on geologic timescales 100 years isn’t nearly enough time for most species to adapt to significantly different conditions. Florida alligators might happily expand their range further north in response to climate change, but that’s different.

As to the larger point, the sun was ~30% dimmer 4.5 billion years ago and will get about 67% brighter over the next 4.7 billion years. While we would be dead long before we could free up all the worlds trapped carbon, in such a hypothetical situation the world isn’t simply returning to an earlier state.

Some people argue that co2 levels were higher in the past. Yeah but the sun was a few degrees cooler. You simply needed more co2 to reach similar temperatures.

The IPCC reports don't predict anywhere near these disasters, even in their worst scenarios.

I'll trust those over a PBS special from the 1900s.

One things for sure, the children born today will be genetically optimistic.

Not a great idea to expect to learn about the world from sensationalist TV. Especially not such an immature field as climate science in the 90's.

You do realize I mean the 1990's right? The show was broadcast in color, so it came after climate change science had "matured".

Concretely, the magnitude of our current predicament was correctly forecast by computer models well before 1980, and the basic mechanisms and effects those models were based on were well-established by the 1960s.

Claims to the contrary have been extensively documented to be part of a paid misinformation campaign the fossil fuel industry ramped up in the early 1980s.

The show wasn't particularly sensationalist, for what its worth. Climate change was a bipartisan concern back then, and it mostly focused on the fossil records that backed up the claims it made. It also talked about the solar cycle's impact on earth's average temperature and compared the magnitude of the effects over time.

All the technology that was needed to head off disaster was already commercialized, assuming a one-two punch, where phase two involved better batteries.

No one imagined we would choose to take no action for another 30 years.

To get an idea of the optimism, Biff from Back to the Future was based on Trump and ends up waxing an engineer's car.

If I had to bet what actor would be president in 2016, I'd have guessed Patrick Stewart, and that his second move (after installing the captain's chair in the oval office) would be pointing at a clean energy plan to replace our carbon nuclear fission power grid with fusion / solar and saying "make it so".

> our current predicament was correctly forecast by computer models well before 1980

So what? There are false climate predictions from back then too, and nobody knew which ones would turn out to be true or false. It was an immature field and predictions were all over the place, including global cooling.

If I produce a dissenting climate prediction, will you produce evidence that that specific piece of research was both paid for by the fossil fuel industry and known to be false by the general climatologist community?

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