The present Covid-19 lockdown provides an ideal opportunity to test one of the fundamental assumptions of the anthropogenic climate change theory by observing its effects on atmospheric CO2 concentration.
According to the Financial Tribune US gasolene consumption has fallen by half over the last 5 months, largely because of the social effects of Covid-19. Meanwhile the US Environmental Protection Agency tells us that greenhouse gas emissions split up according to the pie chart at the top of the page. Since transportation contributes 28% of US emissions, we can expect something like a 14% reduction in emissions. Since a large proportion of the global population is in lockdown, there should be a similar drop in global emissions of CO2. As a ballpark figure let us assume 10%. Only the production rate of CO2 has changed. There is no reason to assume that uptake by the oceans and the biosphere will be any different from the usual seasonal variation. Therefore the fall in emissions may be observable in atmospheric CO2 concentrations.
The above graph shows the monthly mean CO2 concentration measured at the Mauna Loa observatory in Hawaii in red. The seasonally corrected values are shown in black. To the naked eye the noisy variation in the latter from month to month is about 1 part per million of CO2 or 0.25% so that a 10% variation should be clearly visible in the data.
Furthermore there are a number of other atmospheric baseline monitoring stations in the world, viz.:
There are more than 25 such stations, implying that, by averaging the results, the resolution of the measurements can be further reduced by a factor of five to 0.05%. Even a one percent variation in global emissions due to Covid19 should be easily measurable.
At last we have a method of determining what proportion of observed increases in atmospheric CO2 concentration is due to fossil fuel emissions and how much comes from other sources such as volcanoes and deep ocean upwelling.
I predict that the anthropogenic contribution will prove to be less than 20% for reasons given here: On Carbon Dioxide
This is a risky prediction according to Popper’s principles. If it is confirmed, the theory of dangerous anthropogenic global warming can be abandoned.