The climate models have consistently over-predicted warming. This seems to be a consequence of the carbon-based theory of warming: since Co2 is a relatively weak greenhouse gas, to fit prior years the models need a "climate sensitivity" factor beyond Co2 alone, but then the models over-predict what actually happens after. The models are now way out of whack with reality (the black line of measured temperatures, which is way below model projections):
When you hear that warming is "accelerating at a much faster pace than was previously thought", as UN Secy General Ki-Moon said recently, they are incorrect. The data show the opposite: we are cooling faster than previously thought.
A climate scientist from India, Girma Orssengo, suggests a simpler alternative model which better matches historical temperature measurements: a modest trendline up of 0.6C degrees/century since the end of the little Ice Age, masked by a 60-year cycle of warming and cooling that adds 0.3C degrees over 30 years of warming, then subtracts it over the next 30 years of cooling, for a 0.6C swing top to bottom.
This model can explain why the climate models are so off: they are fit to the wrong rate of warming, the swing not the trendline. Something natural is causing the 60-year cycle that is not in their models.
The 20th Century warmed up by around 1.1C degrees, while the model predicts the 21st Century will be flat with essentially no warming at all. Why the difference? The 20th Century started close to a bottom of the cycle and ended at a top, exaggerating warming, whereas the 21st Century will start at a top and end at a bottom, masking warming.
The model has 0.6C rise over 100 years, with a 0.6C swing top-to-bottom. Hence it would predict that:
- a century which starts at a bottom and ends at a top would go 0.6C plus the bottom-to-top swing of another 0.6C, or 1.2C, close to the measured rise of 1.12C of the last century
- a century which starts at a top and ends at a bottom would find the 0.6C rise masked by the 0.6C top-to-bottom swing for a net 0.0C rise
This is easy to see from the chart:
1910 was a low point at -0.64C
2000 was a high at 0.48C
= a 90 year rise of 1.12C
2090 is predicted to be a low point at 0.41C
= a 90 year fall of -0.07C
There is a lot of investigation of the climate sensitivity factor. Prof. Lindzen of MIT has calculated it as much less than in the models: around 0.3-0.6x, not the plugs of above 1.2x in the IPCC climate models.
A new study could be a game-changer: UC Irvine has found that soil microbes have a negative feedback with temperature increases. The models had assumed that microbe Co2 output would increase with warming, not decrease. Since microbe Co2 is 10x human emissions, they could also pull it back out of the atmosphere much faster than humans can put it up there.