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Tim Worstall: WWF’s Casual Casuistry

Tim Worstall, Adam Smith Institute

Global Futures report ignored benefits of GDP growth

A quite startling piece of prestigitation here, we have proof that less is more. True, this is about the “science” of climate change so perhaps not all that remarkable given the manipulations that take place here.

The claim from the WWF’s Global Futures report is that the effects of climate change will cause significant damage to the global economy:

Loss of nature will wipe £368bn a year off global economic growth by 2050 and the UK will be the third-worst hit, with a £16bn annual loss, according to a study by the World Wildlife Fund.

Without urgent action to protect nature, the environmental charity warned that the worldwide impact of coastal erosion, species loss and the decline of natural assets from forests to fisheries could cost a total of almost £8tn over the next 30 years.

It said the loss appeared to be modest at just 0.67% of global income in 2050, but the estimate was conservative and the total was likely to be much higher should areas like the Antarctic deteriorate at a faster pace, causing greater warming and higher-than-forecast sea levels across the world.

The problem with the claim is that it’s nonsense.

The paper is here. Here is actually what they’ve done.

One possible future is called SSP5. This has high economic growth and also high future emissions. Another is SSP1, this has lower economic growth and also emissions.

We’re fine so far. They also say that higher emissions will cause more damage than lower. We’re fine with that as a logical assumption, something internal to the case being built. Then they say that higher emissions will cause damage to ecosystem services, these damages will lead to a reduction of GDP from what it would be in the absence of those emissions/damages. All of this is equally fine as a chain of logic. Sure, it may or may not be true but it’s logically valid.

Then they do something absurd.

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