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Hothouse Earth: It’s Extremely Dodgy

Dr David Whitehouse, GWPF Science Editor

No new science, no new data, no new scenario and consequently no new cause for panic.

It’s been a long heatwave in much of Europe which has prompted questions like ‘what is the influence of climate change on this year’s heatwave?’ Some claim that it’s twice as likely to occur, while others claim that climate change is making it worse. “This is the face of climate change,” says Professor Michael Mann. There is a feeling in the hot air that this summer is showing the way of the future. ‘Expect this kind of thing more often’, is the cry.

Whatever way the evidence points, wherever the argument goes or the temperature changes in the future, the media have loved the “Earth’s on Fire,” headlines. But if you thought that was bad wait for the apocalypse. A new paper claims were are heading to a “Hothouse Earth,” and perhaps soon. Cue the heatwave fever on steroids.

The first thing to bear with the paper that suggest this is that it is a “Perspective” paper in the Proceedings of the National Academy of Science of the USA.

Fig1 from paper.(Click on image to enlarge). — The possible trajectories of the Earth. Towards a ‘Hothouse Earth’ — or a region of stability, if we take drastic action.

Yet, it is not a research paper and contains nothing new in the way of climate science. It is a future scenario pieced together by quoting selected (cherry-picked) references with a lot of hand-waving in-between. The author’s say it’s not conclusive, and they hope it’s not going to be true. They have a responsibility to ask the question, they claim, admitting it’s extreme.

The report starts as it continues. It says the formalisation of the Anthropocene – the controversial ‘geological’ epoch in which mankind allegedly dominates natural processes – is being considered by the stratigraphic community. Just a few days after this paper was accepted for publication, the International Commission on Stratigraphy decided against endorsing the Anthropocene, saying that we live in the Meghalayan Epoch instead. However the authors then go on to say that it is actually irrelevant what the geological community decides, they are going to claim the Anthropocene exists anyway. Human activity, they conclude, now rivals geological forces.

So the authors ask, ‘Is there a tipping point’, a threshold, in climate change and where might it be? How much will the Earth warm and how fast? Earlier this year a paper in Nature revised the calculation of how greenhouse gases drive up the planet’s temperature. It reduced the range of possible end-of-century outcomes by more than half and concluded that any worst-case scenarios were unlikely. It’s not mentioned in the “Perspective.”

Fork In The Road

The paper’s conclusion is that we have already broken out of the Ice Age-Interstitial see-saw of the Late Quaternary (last 1.2 million years), and that the one degree C temperature rise since pre-industrial times is nearing the upper envelope of interglacial conditions. “The Earth system may have already passed the ‘fork in the road’ of potential pathways,” they write, suggesting that the next glaciation might not happen. Next they speculate that, “biogeophysical feedback may be stronger than normally assumed.”

This whole scenario moves into what many would regard as extreme scientific speculation. There is no real evidence in the scientific literature that a rise of global temperatures by two degree C above pre-industrial temperatures will be a tipping point. The most recent report by the IPCC rejected such doomsday scenarios as highly unlikely. There is no new science that this is a threshold after which global warming will become unstoppable. No new science, no new scenario and consequently no new cause for panic. But that’s not the message in the media.

There is nothing wrong with presenting an extreme scenario in order to highlight possibilities and to stimulate research. But as far as presenting it to the public, and as far as reporting it by the news media, it is essential to put it into the context of scientific facts and research. The vast majority of climate scientists are not predicting a Hothouse Earth. This provocative paper contradicts the scientific state of climate research. If it is a warning then it should not be presented as a prediction. It does not warrant all the lurid headlines.

But it has been a very hot summer and a cool approach and rational perspective has gone out of the window like the hot exhaust from an air-conditioning unit. In the words of Dr Phil Williamson of the University of East Anglia quoted in the media, “In the context of the summer of 2018, this is definitely not a case of crying wolf.” Yeah, right.