A group of leading climate researchers has identified a fatal flaw in the climate models that leads them to produce triple the global warming predicted from doubling the CO2 in the air.
CO2 in the atmosphere has some warming effect on Earth’s climate, but undisputed science shows that each additional CO2 molecule we emit has less warming effect than all its predecessors already in the air.
The direct warming effect of doubling the CO2 in the air is generally agreed to be little more than 1 C°. However climate models produce exaggerated warming forecasts by assuming that strongly positive or amplifying temperature feedbacks, such as the increased capacity of warmer air to carry water vapour, a greenhouse gas. They assume that these positive feedbacks will turn 1 C° of direct warming into 3 C° of imagined catastrophe.
They model this assumed feedback with a feedback system-gain equation which is at the heart of every climate model. The equation, however, is borrowed from electronic circuitry. It is not applicable to dynamical systems such as the Earth’s atmosphere.
However, a growing body of learned papers in the climate-science journals (e.g. Lindzen & Choi, 2009, 2011; Spencer & Braswell, 2010, 2011) consider that climate feedbacks are net-negative, moderating rather than intensifying the 1 C° direct warming from a CO2 doubling.
Global temperature has fluctuated by little more than 3.5 C° either side of the long-run average over the past 810,000 years. That range is little more than the range of settings on your home thermostat. If the rogue equation applied to the climate, it could not have been this stable for so long.
The landmark paper from the four researchers, Why models run hot: results from an irreducibly simple climate model, was published in January 2015 in Vol. 60 no.1 of Science Bulletin, the journal of the Chinese Academy of Sciences.
For more info, and the link to the paper see: http://carbon-sense.com/wp-content/uploads/2015/02/simple-pr.pdf [PDF, 883KB]
Keywords: Climate modelling; Monckton, Soon, Legates, Briggs, Bode, CO2 sensitivity.