I was a little surprised recently when Yahoo sent me to a "news" article with the headline "Perth electrical engineer’s discovery will change climate change debate":
A former climate modeller for the Government’s Australian Greenhouse Office, with six degrees in applied mathematics, Dr Evans has unpacked the architecture of the basic climate model which underpins all climate science.Since this article flatly contradicts my own knowledge, I had to dig deeper.
He has found that, while the underlying physics of the model is correct, it had been applied incorrectly.
He has fixed two errors and the new corrected model finds the climate’s sensitivity to carbon dioxide (CO2) is much lower than was thought.
It turns out the UN’s Intergovernmental Panel on Climate Change has over-estimated future global warming by as much as 10 times, he says. “Yes, CO2 has an effect, but it’s about a fifth or tenth of what the IPCC says it is. CO2 is not driving the climate; it caused less than 20 per cent of the global warming in the last few decades”.
Dr Evans says his discovery “ought to change the world”.
“But the political obstacles are massive,” he said.
To put it simply, 97% of climate scientists agree that humans are causing global warming, and I have the impression that there is a consensus not just on the cause but also on the magnitude of the problem. It's a fairly strong consensus, and overturning that consensus will take more than one guy publishing a blog series that one newspaper calls a "discovery". For that reason alone, I would caution you not to take David Evans at his word. Wait for him to publish a properly peer-reviewed paper in a scientific journal, then see how other scientists respond to it.
But of course, at least one scientific group has already published a rebuttal. This rebuttal isn't to the "news" story, but rather to an article that David Evans himself published in the Financial Times. Have a look:
The main error Evans makes here is to claim that climate sensitivity is simply a number churned out by climate models. In reality, climate scientists have used many different lines of evidence to create numerous independent estimates of the planet's climate sensitivity. These include not just climate models, but also empirical observational data (Figure 1 and Figure 2).And here is another article (blog post) from someone who himself debated David Evans on the topic of climate change.