I recently watched a video of an address at a TED presentation by Dr. James Hanson, the subject of which was WHY I AM MOVED TO SPEAK OUT ON MAN MADE GLOBAL WARMING. I was pleased to find this video because I have searched in vain for a clear and simple explanation of why scientists believe that Carbon Dioxide is causing/will cause disastrous climate change. Surely Dr. Hanson, a former head of NASA, could set me straight.
Early on, he mentioned his fascination with the planet Venus, which has a very thick atmosphere of Carbon Dioxide and a temperature of 900 degrees. I took this, perhaps wrongly, as his intended indication of what CO2 can do to a planet. As I often do, I took this information too literally, and decided to test if there is a direct correlation between atmospheric CO2 and temperature. If Venus with an atmosphere of 100% CO2 is at 900 degrees, then earth with an atmosphere of .04% CO2 should be….. .0004 X 900, or —- 0.36 degrees. That can’t be right!
Afterwards, he went on to explain how, since CO2 was absorbing heat that should be radiated back out into space, the earth is getting more heat in than out, resulting in 0.6 watts per sq meter too much heat. I would have thought that, since incoming heat stopped at night, the warmer earth would radiate more at night to even thing up because I had heard somewhere, that warmer bodies radiate more heat than cooler bodies. But I guess that’s not scientific either.
Still, I was waiting to understand how an atmosphere containing 3 or 4 molecules of Carbon Dioxide for each 10,000 molecules of air could cause run-away global warming. It just seems out of proportion. Especially since this 3 or 4 molecules of CO2 had to absorb enough heat in 12 hours to last through the night, collecting enough heat in a nominal 12 hours of incoming to outlast 24 hours of outgoing radiation.
But then Dr. Hanson is a scientist and I am not. Still, I was waiting for the details of just how this miniscule percentage of Carbon Dioxide could change the climate of the entire Globe. But as I waited for this miraculous feat to be explained, Dr. Hanson moved on. He discussed how, in the past, during an ICE AGE, something, (he didn’t mentioned what) caused the atmosphere to heat up a bit. This prompted the oceans to outgas Carbon Dioxide which then took over and melted all the ice. That, he explained, is why in paloclimate studies, a rise in temperature always precedes a rise in CO2. I was glad to find this out because it was looking like a rise in temperature caused the rise in CO2. I am still puzzled, however, because when it started to get cold again when going into another ICE AGE, the temperature began to drop 800 years before the CO2 begin to drop. I was hoping Dr. Hanson would explain this anomaly, but again, he moved on.
He then went to some pains to show that, as the industrial revolution increased the CO2 content of the atmosphere by 1 part in 10,000 (my figures), the temperature increased proportionally (unlike my Venus calculations). He seemed to assume that this was explanation enough to prove that Carbon Dioxide controlled climate. I suppose that I should defer to Dr. Hanson, but I thought that this kind of relationship was called a correlation and I had heard that correlation was not causation. This relation could also mean that a warming climate caused increased CO2.
In conclusion, Dr. Hanson listed all the catastrophic things that were going to happen when Carbon Dioxide increased to 6 or 7 molecules per 10,000 of atmosphere. I guess I shouldn’t rely on my sense of proportion as much as I do, but I do; even knowing that a tiger can crush my skull with one bite, I am not that worried about my kitten.