Feedback Loop Gain From Process Engineering Shows Low Climate Sensitivity

By Collin Maessen on 13th March 2013comment

Climate Changes, But Facts Don’t: Debunking Monckton

On the 19th of July in 2011 the National Press Club of Australia held a debate on climate change. In this video I will be analysing the claims Monckton made during the debate and if they are correct or not.

The reason I’m doing this is that Monckton challenges his critics to check his sources, or like he put it in this debate “to do your homework”. I’m going to follow him up on this to see if the scientific literature, and other available sources, corroborate what he’s saying.

Watch this video on YouTube

Video description

On the 19th of July in 2011 the National Press Club of Australia held a debate on climate change. I will be analysing the claims Monckton made during the debate and if they are correct or not.

In this section Monckton talks about feedback loops and how they show that climate sensitivity is low. I show how these concepts are used and what this means for the argument Monckton is presenting.

Transcript

CHRISTOPHER MONCKTON:
What I will do therefore, since I had, as a condition of taking part in this debate, insisted that ad hominem questions of that futile and drivelling kind should not be asked, I'm going to take a free kick, and I'm going to get back to the climate which is what we are here to debate. Not the way the House of Lords work.

ALEX HART::
Are you then disputing…

CHRISTOPHER MONCKTON:
The IPCCs - no sir - the IPCCs estimate of the amount of warming from a doubling of Co2 concentration, two to 4.5 Celsius, with a central estimate 3.26 Celsius, suggest a feedback loop gain in the climate system of between 0.42 and 0.74 with a central estimate 0.64.

However that is a near impossibility, physically speaking, because in any object on which feedback's operate, if the feedback loop gain is greater than somewhere in a range of 0.01 to 0.1, the object becomes terminally unstable and under conditions which might quite easily occur, the loop gain would reach one, and the system would blow itself apart.

Since this hasn't happened, we have very good evidence from process engineering in this case that once again the likely rate of warming from a doubling of Co2 is one Celsius degree. Thank you.

This is complete nonsense what Monckton said. You cannot use a concept like this to prove that our planet has a low climate sensitivity. The mathematics he's referring to with process engineering are formula's dealing with feedback in an electronic circuit. I don't think that I have to explain why this wouldn't be applicable to the climate nor would it be used by a climate scientist.

Besides, from climate science itself we can show that what he's saying is wrong. In climate science we use a law called the Stefan–Boltzmann law. It describes the main, and powerful, negative feedback in how our planet responds to a forcer. I'll spare you the math, but what it describes is how heat escapes our planet and how you can calculate how much is escaping.

What Monckton described simply isn't possible with the climate sensitivity used by the IPCC nor a possibility with the used emission scenarios. Our planet is simply nowhere near this kind of tipping point.