James Hansen said in his book Storms for my Grandchildren that if we burnt all the available coal, tars, and oil then the ‘Venus Syndrome’ would be a dead certainty, extinguishing life as we know it on the planet. He has now thought further and says that is not going to happen, the time-scales make it impossible. It would take 100 million years to get enough carbon into the atmosphere, and by that time much of it would be back on the sea floor.
However we are on a path to make living at low latitudes impossible, plus more than half the major cities in the world cling to the coastline and are subject to sea level rise. The world, he says, would become ungovernable.
How likely is this? The short answer is that we appear to be on a path to achieve an ungovernable world within a century.
There is another story to be told, one which says that mainstream science is too optimistic, that we are heading for disaster faster than even most climate scientist will admit, at least in public.
For now, just take it that Climate Analytics, a very competent and authoritative outfit, said this last year:
- At present the overall globally aggregated effect of INDCs and current policies put the world on a 3°C or close to 4°C pathways respectively
The INDCs are the Initial Nationally Determined Contributions under the Paris Agreement. Climate Action Tracker says current policies will land us with 3.6°C, with the range 2.6°C to 4.9°C. On that basis 4.0°C looks like at least a 25% probability.
Michael le Page in the New Scientist took a look at our prospects under the latest information.
We’ve had several theories about recovery from disasters, such as hurricanes Harvey and Maria. They vary from ‘creative destruction’ to ‘no recovery’. An optimistic view is that an economy flattened by a big storm will eventually be better off. The pessimistic view is that recovery happens, but the area will never be as well-off as it would have been without the disaster.
Unfortunately studies show the following:
That was after looking at the effects of 7000 tropical storms since 1950 in work carried out be Solomon Hsiang at the University of California, Berkeley and Amir Jina at the University of Chicago, a study done in 2014.
Maria, apart from initial damage, could lower incomes by a fifth. It could take 26 years to get back to where they were before Maria.
Now Jina and Hsiang are looking forward and looking at what might happen in other disasters, such as floods, and in areas beyond the tropics.
Michael Mann says there may be more extreme weather events than the models predict. James Hansen worries that all hell will break loose on the basis of what happened 120 thousand years ago during the Eemian.
Then there is sea level rise. The article says that a 3-metre rise by 2100 is the wort-case scenario. That would be devastating, but most scientists have underplayed sea level rise prospects. The models don’t include the effects of ice sheet decay, because our records of measurement over the last century are a mere moment in time in this issue. We know that serious melting of ice sheets has started in the last 10 years.
I’ll stick with what I wrote in Scoping long-term sea level rise, where I said:
- 380 (360-400)ppm gives a temperature variance of 2.7 to 3.7°C and SLR of 25m (±5)
- 500 (400-600)ppm gives a temperature variance of 5 to 7°C and SLR of 75m (complete deglaciation).
We are currently at 403ppm and most think we’ll get to around 550ppm during this century, or double pre-industrial. SLR plays out over centuries and millennia, but it can happen rapidly under the right circumstances. I suspect 5-metres by 2100 is about the worst case scenario. As to the longer term, I suspect we’d be better looking at ‘back of the envelope’ calculations based on David Archers 2006 graph:
We really have no idea, but we should expect around 20 metres SLR for each degree of temperature rise. We also don’t know what would happen to ameliorate the situation if we reduced emissions to net zero.
Meanwhile in the immediate future the biggest impact could be from the straight temperature rise. Jina and Hsiang looked at this as far back as 2015, would you believe.
They found that when a country’s average temperature 24/7 over the whole year was at 13°C, maximum agricultural productivity is achieved.
At present the Earth’s average is about 16°C:
That image is calibrated in Kelvin, which shows in absolute terms how hot the place is. I think it does a good job in showing the relative warmth of different parts of the planet.
Back to the serious stuff, there are two problems with temperature increase alone. One is that it becomes too hot to work outside in some areas. The other is that productivity and GDP drops away rapidly. The study suggests a 23% drop in incomes on average, and rising inequality. The effects are from 2.5 to 100 times greater than previous modelling suggested.
So here is the impact of 4°C worldwide:
Of the major economies, India, Indonesia, Brazil and Mexico are completely stuffed, The US, Spain, Italy, China and Australia are in bad shape. Germany, Britain and the UK along with Belgium, The Netherlands and Denmark could be OK, but then there is sea level rise.
There are uncertainties in all this, but the risks are astonishing.
Now you may have heard coming out of climate talks in Bonn that emissions were up a bit in 2016, but had been flat in 2014 and 2015, and they expected them to return to flat in 2017.
Don’t believe a word of it. Those scientists are simply not looking in the right place. It’s embarrassing. Here is the latest from the WMO via NASA:
That’s not just from Mauna Loa, it’s from stations all around the globe:
In reducing emissions, we are achieving in net terms exactly nothing. We are in trouble, deep trouble.
Indications are that there is going to be a population collapse of Homo sapiens in the future not too far away. If we get our act together on emissions, we may still need drastic solutions in other areas. Energy from the sun is virtually unlimited, and we may be eating synthetic food. But or politicians and policy makers are walking backwards into the future.
A final warning. The above is based on a linear response of earth systems to climate change. We can be almost certain the response will not be linear. And there is also the matter of low probability, high impact events, which could trigger further tipping points.
Just about anything could happen, short of the Venus Syndrome.