Tamas Calderwood writes: Seeing as Tim MacKay (comments, Friday) attended both my universities with me and played fullback on my rugby team, he knows full well that my qualifications are in economics and finance, not in climate science. But I do know numbers and I read lots of climate science, so I can say quite confidently that the world has not warmed for 13 years, that the three warming spurts of the last 150 years were the same magnitude and that the world was warmer during the medieval and Roman warm periods -- indeed, the world has been warmer for 80% of its 4.5 billion years.
These facts do not support the hypothesis that it's our gasses that are warming the planet. And I refuse to submit to the cult of credentialisation that insists you need a PhD in climate science to legitimately argue these points. You don’t; It’s a simple hypothesis (the world will warm) and the data is incontrovertible (it hasn't for 13 years).
To answer Tim's specific questions: I ascribe a 100% probability to climate change existing. I just think humanity's 4% share of a trace gas that constitutes only 0.038% of the atmosphere is irrelevant because far greater natural forces are at work. Any risk management actions should be based on adaptation to any warming (or the far greater threat of cooling). Attempting to control the climate, particularly via a tax, is simply insane.
Finally, I think business should take no role in climate change, just as I think business should take no role in Earth's slowing rotation, the Sun’s fusing of 620 million tons of hydrogen per second or the accelerating expansion of the known universe. There is no possible role for business in these things, so why waste billions pretending?