A BBC-style fact-check

From Climate Scepticism

BY JOHN RIDGWAY

According to the BBC, we now live in a world of misinformation and fake news, in which fake experts and denialists peddle anti-science conspiracies that endanger us all. This has led to the establishment of fact-checking, in which the so-called denialist claims are seemingly debunked by self-appointed arbiters of the truth. To illustrate how these fact-checks often work in practice, I offer you the following fictional account of how the BBC Verify team might deal with one particularly interesting online talking point that is currently gaining traction. In keeping with fact-checking tradition, we start with a clear declaration of the ‘misinformation’ to be debunked:

One of the most recent of false narratives to appear on the internet has been the assertion that 3.0 is greater than 0.85, a view favoured by climate change deniers, seemingly based solely upon a rudimentary understanding of mathematics gained at a very early stage in their education. But is it really true that a number such as 3.0 can be said to be greater than 0.85? In the simplistic world of the fake expert, the answer would be yes, but in the world of climate change risk management, in which the vast majority of the world’s scientists are in agreement, a much more nuanced and context-driven reality emerges.

The problem with the naïve pseudo-mathematics of the climate change denier is that it often fails to understand the true importance of the numbers concerned, but it is only when this importance is taken into account that reliable statements can be made regarding magnitude. The fake experts will point out that when the units are the same, the numbers are directly comparable. But that is where the misdirection is introduced. Using the same units is only part of the issue. And nowhere is this more apparent than in the recent and rapidly spreading online conspiracy theory that 3.0 is greater than 0.85. To get to the bottom of the matter we consulted our specialist disinformation specialists team to find out where this false narrative is coming from and why it is fake news. This is what they had to say:

“This particularly damaging example of misinformation seems to have started with the publication of a study that showed how climate models have predicted that climate change will lead to a 0.85 metre rise in sea level within the next century for the South Eastern city of Jakarta.”

But is this particular 0.85 actually equal to 0.85? Well, according to our fact-checkers, the answer seems to be ‘probably’.

“According to the models, the figure of 0.85m is the most likely extent of the sea level rise, but the models contain a lot of uncertainties. Accordingly, the value of 0.85 is just a guess. Furthermore, it is based upon a premised 5^oC warming relative to 1870, which is far from certain. However, it is a very worrying figure, and that is what is important.”

Yes, but how does this explain why some deniers have wrongly come to the conclusion that 3.0 is greater than this figure?

“Well, if we were dealing with an even greater level of global warming, the models would indeed predict an even greater sea level rise, possibly even 3 metres or more. In such circumstances 3.0 would certainly be greater than 0.85 because that would be an even more worrying impact of climate change. But that is not where this particular 3.0 has come from. This 3.0 is due to the fact that the city of Jakarta has already sunk by over 3 metres in the last 100 years due to subsidence (with 2.5 of that happening in the last decade). And the rate of subsidence is accelerating, so another 100 years may very well result in a further 3 metres of subsidence at the very least.”

But surely that is a lot more worrying than a 0.85 metre sea-level rise and so this 3.0 is more worrying, and hence it is surely greater than 0.85.

“Well, you might think so but you would be applying the naïve mathematics of the climate change denier. That is not how climate risk mathematics works because, according to experts, “sinking land reinforces the problem of climate change-driven sea-level rise“. For something to be a reinforcing factor it cannot, by definition, be of greater magnitude than the factor it is reinforcing. If it were, then the reinforcing would be the other way round. And since a land drop of 1 metre is equivalent to a sea-level rise of 1 metre, the only way in which the subsidiary role of subsidence can be explained is by recognising that 3.0 is actually less than 0.85, despite appearances.”

So is this all about climate change deniers yet again failing to understand how the scientific method works?

“Certainly. And it is a classic case of facts being taken out of context to prove a point. It may be a fact that in disciplines such as civil engineering 3.0 is always greater than 0.85, but that doesn’t mean that the same can be said in climate science, where a huge scientific consensus exists to tell us that sea-level rise due to climate change is the greatest threat faced by coastal cities. Insisting on retaining the narrow (and quite frankly irrelevant) mathematical sense in which 3.0 is greater than 0.85, is tantamount to denying the scientific consensus, and is just typical of the logical flaws employed by the denier. To the layperson, such arguments may appear convincing but to anyone steeped in climate science the claim that 3.0 is greater than 0.85 just doesn’t make any sense because that would mean that subsidence is a greater problem than climate change-driven sea-level rise, which according to nearly every scientist in the world isn’t true. That is why, when the BBC reported on this problem it was keen to stress that subsidence only represents a ‘bigger immediate problem’. In the long term, subsidence is still only reinforcing the problem.”

Are there any other numbers that climate change deniers are pushing as being greater than 0.85?

“Yes. Shanghai and New Orleans had both subsided by more than 2 metres in the 20^th century, leading climate change deniers to falsely conclude that such cities are more at risk from simply sinking into the sea over the next hundred years than they are from being overwhelmed by a posited 0.85 metre sea-level rise. They also argue that since Shanghai has obviously adapted to its historical 2 metre subsidence without too much fuss and bother, it should also be able to adapt to a 0.85 metres sea-level rise. Once again, these arguments only make superficial sense due to an insistence on sticking to the inappropriate belief that 2.0 is greater than 0.85, thereby denying the consensus within climate science that climate change-driven sea-level rise poses the greatest risk. In fact, there are a host of numbers that have been falsely deemed to be greater than 0.85 based on the likelihood that the majority of coastal cities in the world will, under their own weight, subside by a figure significantly greater than the magnitude of sea-level rise predicted by climate models (albeit, only greater in that consensus-denying mathematical sense beloved of denialists).”

So there you have it. The science is clear. Climate change will lead to inundation of coastal cities due to sea-level rise unless we immediately abandon fossil fuels. Any suggestion that coastal cities are going to sink anyway, leading to far greater inundations than are predicted by climate models, is a false narrative spread by climate change deniers employing mathematical trickery that fails to take into account the existence of a scientific consensus.

The science is settled. Numbers are just denialist talking points. Consider yourself debunked.

Further Reading:

You may wish to read this for an account of ‘climate reductionism’ and the problems facing Jakarta. The false narrative that subsidence is merely a reinforcing factor is clearly impeding Jakarta from dealing with its flooding problems.

For the standard, approved narrative, in which the scale of the subsidence problem is downplayed and framed as a reinforcing rather than principal factor, you may wish to read what ClimateCheck has to say on the matter.