by Andy May, Jan 7, 2023 in Petrophysicist
No minimally informed person denies that climate changes. The climate has always changed. Since 1860 the predominant climate change has been warming, which is fortunate because if we had a winter like those of 1800-1850, we would be in for a shock. No one has been able to prove that global warming is primarily a consequence of our emissions. It is reasonable to assume that increased CO2 has contributed to warming since the mid-20thcentury when our CO2 emissions increased significantly, but no one knows how much they have contributed, no matter how much the Intergovernmental Panel on Climate Change (IPCC) insists that “humans are the dominant cause of observed global warming over recent decades.” (IPCC AR6, page 515).
There is no evidence for this statement. I know this because I have read thousands of scientific papers looking for it. And no, computer models are not evidence of anything but the programming skills of their authors. Models and their predictions are constantly changing and when our knowledge of climate changes, they must be redone.
The absolute lack of evidence contrasts sharply with the decision to cut our CO2 emissions to zero by completely changing our fossil fuel-based energy system and calling CO2 a pollutant—when it is as essential to life as oxygen. All this while most of the world doesn’t give a damn about emissions and many are only on board for the promised money.
To get to the good news about global warming we need to look at variations in the rate of global warming, i.e., the speed of warming. Today we are going to use satellite-calculated global temperature data from the University of Alabama in Huntsville, UAH 6.0. They are plotted in Figure 1.
Figure 1. UAH satellite global temperature anomaly data in °C relative to the mean from 1991 to 2020. In green is the linear trend of the series (+0.13 ºC/decade) and in blue is the linear trend since 2016. Data: UAH 6.0Graph: Woodfortrees.
As we can see, the temperature trend decreases since 2016, so 2022 is the seventh warmest year. For 7 years the planet has been cooling. Does that mean that warming is over? No, periods of 7 years of cooling are frequent in the record, there being 8 of them since 1979, and the warming continues. But there is only one period of more than 15 years of cooling, from 1998 to 2014, that appears in the record for the last 45 years. It is known as the “Pause.”
To analyze the evolution of the warming rate, we subtract from each monthly data the previous one to calculate the monthly increase. We then deseasonalize the monthly increase by finding the 12-month moving average to remove a lot of the noise. Finally, we calculate the 15-year average warming rate in °C/decade by calculating the 180-month moving average and multiplying the resulting data by 120.
Figure 2. Evolution of the warming rate for 15-year periods between 1979 and 2022 in °C/decade and its linear trend, from monthly UAH 6.0 satellite temperature data.