Do Negative Feedbacks Dominate The Earth’s Climate System?
April 30, 2011 1 Comment
UPDATE: If negative feedbacks dominate, then AGW theory (which attributes the current warming to well-mixed anthropogenic greenhouse gases) is ill founded. AGW depends upon the strength of these (+ or -) feedbacks, and negative feedbacks would essentially dampen out the AGW components of any natural global warming cycles. So far, there has been no sign of a “runaway greenhouse effect”, as theorised, where positive feedbacks lead to the evaporation of all greenhouse gases in the atmosphere.
Therefore, as far as the earth’s radiation budget is concerned, there is no evidence that positive feedbacks dominate the earth’s climate system—not anything we can measure realistically and accurately. (Note: when climatologists refer to “positive feedback” they really mean “weak negative feedback”, to use electrical engineering terms.) However, there is some evidence that negative feedbacks dominate. For example, oceans could act as negatives feedbacks, as determined by cloud and water vapour, and plants in response to increases in CO2.
[I’ve fixed some of the dead-links and clarified negative feedbacks more.]
“What this means is that though CO2 is probably warming the Earth, the climate will prove increasingly resilient to extra CO2. Greenhouse gases will not increase temperature much more than 1C in total because positive feedbacks (or “weak negative feedbacks”) predicted by computer models will not occur.”
Climate sceptics rally to expose ‘myth’
‘Lindzen on negative climate feedback’
‘When is Positive Feedback Really Negative Feedback?’
‘CERES imagery of Earth’s radiation budget’
‘Strong Negative Feedback from the Latest CERES Radiation Budget Measurements Over the Global Oceans’
31 July, 2010