Point of No Return

The IPCC produces simulations which describe various pathways to keeping climate change below the 2°C limit (and another set for below the 1.5°C limit). In the IPCC’s fifth assessment report which came out 2013-2014, all the simulations for limiting temperatures to a 1.5°C rise and most simulations for a 2°C rise required negative emissions.

Now negative emissions are an unexplored technology. We have no mechanism for doing them which actually works, nor are we researching such things. Moreover all proposed mechanisms have massive detrimental side effects.

I found this scary.

The IPCC reports have not looked at tipping points in the past. These are too hard to model because we don’t know enough about them. Once a tipping point is passed, however, nothing we do will have any effect (for a while). Even if we could stop emissions completely the effects of the tipping point would continue to cause the planet to warm.

In one sense this is terrifying. We need to know the worst case scenario. Or as close to it as we can get. But the IPCC refused to even look at such cases until the 1.5°C report which came out last year.

I have recently read articles which show that we have passed two (linked) tipping points.

The first is about Arctic sea ice. Even if we halt emissions now (which we won’t) the Arctic will warm by between 3-5°C. The oceans are so warm that more sea ice will melt. Less sea ice means the  waters (which are darker than ice) of the Arctic ocean will absorb more heat causing the oceans to warm causing more sea ice to be lost. There’s nothing we can now do to stop this now.

OK, but if the Arctic warms by 3°C does that really matter? I don’t live in the Arctic. Interesting that this question is not addressed save in generalities “What happens in the Arctic does not stay in the Arctic”.

The second tipping point is a bit more obscure and less well accepted. Back in 2014 people noticed that atmospheric methane was on the rise. Methane is a far more potent greenhouse gas than CO₂, until recently it has been mostly ignored by the IPCC because it didn’t seem relevant, there isn’t much of it in the atmosphere and it’s concentration wasn’t increasing. But in the last 5 years that has changed. Methane levels as measured but satellites have risen very fast.

Methane is stored in vast quantities in the Arctic permafrost and in methane clathrates in the seabeds. As the temperature warms the both the permafrost and the clathrates melt. This releases more methane which traps more heat which melts more permafrost and so forth.

Given the way atmospheric methane is behaving we appear to be passing this tipping point as well.

Of course this is positively linked to the melting sea ice, both of these effects will warm the world which in turn makes the both effects stronger.

In the past, climate change has happened abruptly (on a geological timescape anyway) and the release of methane from the Arctic appears to explain much of this behavior.

Then I ran across this gem of a paper, which came out last year, but I only noticed recently.

The author expects a major environmental catastrophe in the next decade or so, and warns us to start thinking in those terms.

Now a major environmental catastrophe is likely to be accompanied by civil unrest. When there isn’t enough food on the table, people tend to riot. And go to war.

The effects of even a small nuclear war (Say, India and Pakistan exploding about one third of their arsenal) would ultimately kill about 2 billion people.

And if the US or Russia or China released their arsenals?

In other words, the extinction of the whole human race has become a probability in the near future.

I don’t see much hope myself. I think we have now passed the point of no return with respect to climate, and human life in general.

Good-bye.