What is the evidence and logic supporting the official narrative that man-caused CO2 emissions are causing a dangerous global warming that left unchecked will have catastrophic consequences for humanity?
The foundation for government climate policy worldwide is The United Nations Framework Convention on Climate Change (FCCC) , an international environmental treaty addressing climate change, negotiated, and signed by 154 states at the United Nations (UN). Its policy recommendations are based on reports developed by the Intergovernmental Panel on Climate Change (IPCC), an intergovernmental body created in 1988 by two organizations of the UN. Its mission is to provide the world with “objective, scientific information relevant to understanding the scientific basis of the risk of human-induced climate change, its natural, political, and economic impacts and risks, and possible response options”. The IPCC periodically issues an “Assessment Report” (AR) designed to “contribute to the work of the FCCC”. The IPCC’s Fifth AR, the most recent, was released in three volumes in 2013 and 2014; it served as the basis for the FCCC’s Paris Agreement in 2015. The sixth AR will be released in 2022.
The IPCC issues a “Summary for Policymakers (SPM) with each AR, which is supposed faithfully to reflect the plethora of scientific papers underlying an IPCC AR.
The message of the AR5 SPM is indeed alarming. It states, “Warming of the climate is unequivocal, and since the 1950s, many of these changes are unprecedented over decades and millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, the sea level has risen, and the concentrations of greenhouse gases have increased)” (AR5, 2013,4. “It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century” (AR5 2013,17).
The case for a man-caused global warming disaster rests heavily on over a hundred global climate models (GCMs). The inputs for these models are surface-based temperature datasets. Their structure is based on the following assumptions:
- The sensitivity of climate change to CO2 concentration is high.
- The change in CO2 concentration is due mainly to man’s activities.
The output from the models project a large temperature increase over this century. The projected rise in global temperature is then used as an all-purpose explanation for unprecedented upcoming disasters, e.g., rising sea levels, more severe, damaging weather events, habitat destruction, etc.
The entire case for climate alarmism is embedded in the models the IPCC – and therefore governments worldwide — use to convince the public that drastic action is necessary. If the models are wrong, the case for activism in response to alarmism collapses.
GCMs invariably “run hot”, i.e., over-predict the rise in temperature. Due to the shortcomings of the HadCRUT4 database and other temperature records based on surface-based weather stations, the only reliable global temperature record is the one derived from satellite-based readings of lower atmosphere temperatures taken since 1979. When that forty-year record is used to test the accuracy of the GCMs that purport to show the impact of human activity on Earth’s climate, the models invariably fail, revealing that man-made CO2 has little or even no influence on global temperatures. After taking into account inconsistencies in the global temperature record, it is clear there has been little global warming since 1998 and even earlier in other parts of the world. The IPCC has admitted there is uncertainty regarding the measurement of global temperatures. In its latest report (AR5), released in 2013, the IPCC admitted that the global mean average temperature stopped rising for the fifteen-year period from 1998 to 2012 (Singer, p.130.