Dr. Ross McKitrick, University of Guelph, explains that the "pause" in global warming reveals that there are flaws in the climate models. The models say there should be an increase but there is no increase in global temperature. “Social costs of carbon” are based on faulty climate models, not reality.
Dr. Clive Best reviews the IPCC fifth assessment report (AR5) attribution statement, which is based on comparing climate models to the global temperature record before this century. The statement "depends critically on them [models] being able to simulate both anthropogenic forcing and natural variability. Chapter 9 of the IPCC report shows that models are tuned so as to describe past observations. The model control runs exhibit long-term drifts. Any ‘natural’ trends generated by models in the temperature data are assumed to be an artifact and simply removed. The procedure assumes there in no natural climate change despite the recovery from the little ice age. However, the Atlantic Multidecadel Oscillation alone added 0.2 C warming to the 1950 - 2010 trend. The result is that the AR5 attribution statement is useless.
The IPCC fifth assessment report failed to provide a best estimate of equillibrium climate sensitivity. Christopher Monckton of Brenchley uses the feedback parameters published in the report to determine realistic estimates expected global warming to the year 2100. He finds that global temperature could rise by up to 2.1 C by 2100 if the reported feedback parameters are correct, which is much less that the 3.7 C estimated to the RCP 8.5 emissions scenario. Monckton's best estimate is that the feedbacks are net zero, giving a temperature rise of just 3/4 of a degree Celsius by 2100.
Climate models and observations were compared over a 55-year span (1958-2012) in the tropical troposphere. The paper finds that climate models are inconsistent with three weather balloon series. The models not only predict far too much warming, but they get the nature of the change wrong. Models show a smooth upward trend but the observations show all the warming occurred in a single step-change in the late 1970s, known as the Pacific Climate Shift, and no significant trend before or after. Dr. Ross McKitrick explains the new paper is this Climate Audit post. Over the 1979-2009 interval climate models on average predict 2x and 4x too much warming in the tropical lower- and mid- troposphere layers, respectively.
While the Intergovernmental Panel on Climate Change (IPCC) still uses the iconic word “unequivocal” to describe warming of the climate system over the past century, a new word has slipped into its lexicon: the “hiatus.” They have begun referring, with a bit of hesitant throat-clearing, to “the warming hiatus since 1998.”
Cracked-beakerBoth satellites and surface records show that sometime around 2000, temperature data ceased its upward path and leveled off. Over the past 100 years there is a statistically significant upward trend in the data amounting to about 0.7 oC per century. If one looks only at the past 15 years though, there is no trend.