Forty years on

The Limits to Growth report is nearly 40 years old. I read it when it was published and was dismayed that it seemed to gather more negative than positive assessment. At last there is a government response to it: Government review to examine threat of world resources shortage.

RealClimate has an excellent discussion on “How do we know what caused climate to change?”: On attribution is by Gavin Schmidt whom I find the sanest exponent of global warming issues. For the mathematically inclined there is a link to a beautiful discussion of stochastic versus deterministic trends: Not a Random Walk. It is worth comparing these with the petty put-downs being thrown at Gavin: Real Climate’s Gavin Schmidt: A Foot in His Global Warming Mouth by John O’Sullivan, guest post at Climate Realists. Real scientific discussion requires a lot of detail. Sometimes for general interest one has to miss some of the irrelevant details. The complaint is that in a discussion, Learning from a simple model, Gavin mentioned a factor two in an equation because the atmosphere radiates up as well as down, when really any volume of the atmosphere radiates in all directions. So Gavin was not strictly correct. However, if you do the math properly the factor in the equation is indeed two – the sideways radiations are not relevant, what matters is what eventually goes straight up and straight down (I had better say at the point on the earth that you are considering else someone will say that up & down depends where you are). Why did John O’Sullivan not do the math to show that Gavin was wrong in essence? – because Gavin was not wrong.