A mathematical joke asks, “What do you get when you cross a mountain-climber with a mosquito?” Answer: “Nothing: you can’t cross a scalar with a vector.”
Non-mathematically minded readers may not get the ‘joke’ until later in this article. But when you do, you may feel it’s the most expensive ‘joke’ told, and it’s being played on you and me.
If you’ve ever followed the heated debate about man-made global warming you will know the cornerstone of that science is the so-called “greenhouse gas effect” (GHE). It is purported that rising human emissions of carbon dioxide (CO2), one of those so-called GHE gases, is dangerously adding to climate change. The chosen remedy of western governments: we must all pay more taxes, cut back our industrial emissions and invest in various questionable alternative energy schemes to avert a planetary crisis.
To this end, many a (government) climatologist or Greenpeace activist will regale you with the glib assertion that the GHE makes our planet “33 degrees warmer than it would otherwise be.” But where does this “33 degrees” number come from and is it scientifically valid? Contrary to media hype this number is not “an observation” it is the product of a 30-year-old calculation from a team of researchers led by NASA’s Dr. James E. Hansen. It is a ubiquitous claim that the number “proves” the GHE is real. [1,2]