Bjorn Lomborg

Bjorn Lomborg’s climate trickery

Craig Kelly has been posting tweets from climate change critic Bjorn Lomborg. So it is worth checking out Bjorn’s track record.

Unfortunately, it seems that Bjorn has used his considerable abilities to misinform.

A track record of deception

Bjorn Lomborg has been a polarising figure in the public discussion of climate change – I have written more about him here.

He accepts that climate change is occurring and needs to be addressed. But he disputes much of the science, and believes many expressions of climate science are “alarmist”. He argues the accepted plans to address climate change are uneconomic.

He has been accused of dishonesty and misrepresenting scientific data. His scientific credibility has been assessed as low or very low.

One of the most common charges has been that he misrepresents data by carefully choosing only that data that supports his conclusions, while ignoring the larger part of the data that is contrary to his conclusions, a fallacy known as “cherry picking”.

Here are some examples.

Misusing fire data

In a recent discussion, Bjorn used data on bushfires in Australia to argue that climate change is not affecting bushfires significantly because the total area burnt has more than halved in the past century.

But there are things he didn’t mention:

  1. The data he used included fires from two very different causes: (a) fires lit by rural landowners to clear land for grazing, a common practice in the past but not now, and (b) naturally occurring fires affected by a warming climate. There are less of former but more of the latter.
  2. The older fires were mostly in grasslands in the inland plains. These fires were not nearly as ferocious or damaging to infrastructure and wildlife as recent fires in forested country.
  3. Thus other measures of the severity of bushfires may be better indicators of climate change, e.g. species lost, the value and type of land burnt, and the severity and ferocity of the fires. The recent fires were much worse on these criteria.
  4. The conditions making bushfires more destructive are all made worse by a warming climate. Recent fires have been so fierce they generated Pyro-cumulonimbus clouds, which can spread the fire rapidly.

Thus the data supports the opposite conclusion to the one Bjorn was presenting. Climate change really is making bushfires worse in Australia, as firefighters and climate scientists know. Lomborg cherry-picked the data.

More cherry-picking

In 2015 a Lomborg article in The Wall Street Journal was fact checked by seven climate scientists. The results were published by Climate Feedback, which is a worldwide network of scientists sorting fact from fiction in climate change media coverage.

Lomborg’s article was tagged as “Cherry-picking, Flawed reasoning, Misleading” and its scientific credibility was assessed as “low” to “very low”. The scientists said:

“The main reason for this negative evaluation is that the author practices cherry-picking: he is selecting limited evidence to support his thesis …. The evidence provided is insufficient: several examples are either inaccurate or only speak about one aspect of the problem, ignoring much of the published literature on the subject.”

The scientists pointed out that Bjorn Lomborg referred to a recent plateau in global mean temperature, but he ignored the long term temperature record that showed that most of the warmest years on record had occurred in the past 15.

Climate sceptics commonly pointed to this “plateau” around 2010 when global temperatures stopped rising for a few years. But it wasn’t long before temperature began rising again, and the last 6 years have been the hottest ever recorded.

Trends cannot be determined in such a short time, and Lomborg should have used the whole data record available at that time (which showed the rising trend) instead of using only recent data.

Using incorrect data

Bob Ward from the Grantham Research Institute on Climate Change and the Environment at theLondon School of Economics and Political Science has been a strong critic of Bjorn Lomborg’s economic statements.

He outlines several examples of Lomborg’s “misuse of outdated, concocted and misinterpreted numbers” (here) and “misrepresentations and false claims” (here).

He concludes Lomborg has “a long track record of being an unreliable and inaccurate source of information about climate change”.

Knowing who to trust

Bjorn Lomborg has qualifications in Political Science, not climate science. The consensus of climate science is contrary to much of what he says.

He has been criticised again and again for cherry picking data and misreporting facts. With his qualifications, it is hard to see how this could be accidental.

It is a pity because he could be bringing useful economic and social insights to how we can best address climate change. Instead, we have to be wary of anything he says.

As always, it is best to follow the established science until and if we are given far better reasons against it than Lomborg provides. And if that happens, the consensus of science will change.

Read more background on Bjorn Lomborg on this site.

Photo from Bjorn’s web site Publicity photos.