Two years ago I posted the latest plot of global temperature, and argued that if trends continue, as they are likely to do, the Great Barrier Reef has little chance of surviving beyond 2030 as more than a sad remnant in its southern reaches. Even if we suddenly got serious about reducing greenhouse gas emissions the warming will still continue for 2-4 decades, and the damage would only be deferred.
The greater danger is that the warming will tip into being irreversible if it is not soon reversed. In that case our grandchildren would inherit a very different and hostile world.
There is a climate crisis. Deniers commonly have one or two facts that they claim show the scientists are wrong: the climate has always changed, carbon dioxide is only a tiny fraction of the atmosphere, and so on. They have an endless supply of supposed justifications for doing nothing.
Evidently the deniers imagine the climate scientists never thought of these objections, never investigated them. Well, they did.
There was no big revelation, just a train of thought. Nearly a quarter of the Great Barrier Reef is dead, and there has been no discernible political response. Global temperature is rising off the chart, only glancingly noted in the torrent of chatter. The decades-long trend of ever-more perverse and destructive politics continues. Societies are fragmenting.
For perhaps two decades I have held to the thought that while ever there was a chance of avoiding a planetary tipping point I would continue explaining how we can avoid the worst. Through that time, the path to a healthy, stable world has become clearer and more obvious, demonstrated in a thousand practical, small-scale ways. All that time the window of opportunity was closing. It is, in my judgement, barely open any more.
An article by Bob Douglas on the dire need for real political leadership prominently features Sack the Economists, along with a new book by prominent Australian economist Ross Garnaut, Dog Days: Australia After the Boom, the latter launched by prominent Liberal politician Malcolm Turnbull. Tony Abbot deposed Turnbull as Leader of the Opposition in 2009, winning by one vote, otherwise Turnbull would probably now be Prime Minister.
See Bob Douglas’ article in the Sydney Morning Herald here. It also appears in the Melbourne Age and the Canberra Times.
The IPCC (InterGOVERNMENTAL Panel on Climate Change) cops a lot of stick for allegedly being radical, part of the great climate-science-greenie-leftie-jewish-commo conspiracy, etc. But in fact it is too slow and conservative, witness the world is tracking on the high side of its projections.
One IPCC habit that annoys me is running projections only to the year 2100. We know warming and its consequences won’t stop there, so the choice is pure bureaucratic nonsense.
Here is a rare example of a more useful graph, showing warming continuing for more than a century beyond 2100. God knows what sort of world our great- … – grandchildren would be contending with.
You may have read or heard that the shrinkage of the Arctic sea ice recently smashed the previous 2007 record low. You may not have heard of a new study that says we might, just, still have a chance of keeping global warming below 2°C. You may or may not have heard that some prominent climate scientists, including James Hansen, think 2°C is too high, and we need to keep warming below 1.5°C or even 1°C.
All this means we might still have a chance of avoiding “dangerous” global warming, but the chance is already small, and diminishing very rapidly. It also means we are not doing nearly enough to reduce greenhouse gas emissions, even though there is a great deal more we can do at quite modest cost to our economies.
Climate negotiators in Durban have agreed to a “roadmap” that would leave the world at high risk of severe or catastrophic global warming. They have belatedly agreed to discuss adopting outdated targets that would not come into force until 2020, far too late by current climate criteria.
Recent studies require greenhouse gas emissions to be reduced much faster than previously proposed, to give us even a moderate chance of keeping warming below two degrees Celsius (2°C). Meanwhile the climate science now says the threshold of “dangerous” warming is only 1°C.
[This is a draft. Over the next week or so I will be revising, adding links and making other versions to send to any news outlet that might take them.]
Here is the climate news. The real climate news.
So far the world has warmed about 0.6°C. If currently advised reductions of greenhouse gas emissions were realised there would still be a 90% chance global warming will exceed two degrees Celsius (2°C). 2°C used to be regarded as the threshold of “dangerous” climate change, but new science has shifted that threshold to only 1°C. 2°C is now regarded as the threshold of “extremely dangerous” climate change. At that level, global warming effects would be widespread and severe.
However, somewhere between about 2°C and 4°C lurks a tipping point, beyond which global warming will run beyond human control, driven by natural feedback mechanisms that drive temperatures higher, perhaps to 6°C or 8°C, no-one knows. 4°C would already be “incompatible with an organised global community”. Higher temperatures could result in the extinction half or more of the world’s species and much of the human population.
There’s not much more to say, really, about how we’re dealing with global warming:
“We’re running an epic experiment on global biophysical systems with only the faintest clue what we’re even doing, much less how to manage it. We know things could go rapidly, irreversibly, horribly wrong, but we’re not sure how likely that is, or when it might happen. So we just blunder ahead at top speed. Because coal is cheap.”
From an article by David Roberts of Grist. He’s commenting on a commentary in Nature Geoscience pointing out that climate models are not good at predicting tipping points.