By Christopher Monckton of Brenchley

By the time you read this, the monthly Mauna Loa CO₂ concentration will probably have been published. The profiteers of doom have been delighted by the global Chinese-virus lockdown, which many of them would like to be permanent.

As John Christy reported here yesterday, in March the UAH dataset maintained by Roy Spencer shows the second-biggest month-to-month drop in global mean lower-troposphere temperature since the record began in December 1978.

But, as Anthony Watts pointed out in a comment, the fall in temperature owes nothing to a decline in CO₂ concentration, whether or not caused by the lockdown. The keepers of the Mauna Loa record agree with him:

Let us assume that there has indeed been a 25% decline in our sins of emission, and that it will persist until the pandemic ends in 18 months’ time, as some epidemiologists have predicted. Let us also assume that there will be a further 0.2 ppmv reduction in CO₂ concentration for each of the next 18 months. Then the CO₂ concentration will have fallen by a dizzying 3.6 ppmv.

Maybe. For IPCC says CO₂ persists in the air for about 125 years, in which event nothing we do this century will make much difference to CO₂ concentration.

However, just for fun, let us imagine that over the next 18 months the concentration does indeed fall by 3.6 ppmv. Let us work out how much global warming the tens of trillions that the Chinese-virus lockdown has cost us will have bought.

In March, the Mauna Loa CO₂ concentration C₀ was 414.5 ppmv. At the end of the pandemic, then, C will be 410.9 ppmv. Let us pretend that, as the Thermageddonites wish, it would not bounce back to where it is now, but that the pandemic will reduce all subsequent CO₂ concentrations, whatever they might otherwise have been, by 3.6 ppmv. Let us also pretend that the reduction will occur immediately, rather than in 125 years’ time.

The coefficient k in the CO₂ forcing equation is 5 (derived from Andrews et al. 2012). The Planck or zero-feedback sensitivity parameter P is 0.3 K W^–1 m² (ibid.). The system-gain factor G from feedbacks is the absurdly exaggerated 3 imagined by IPCC et hoc genus omne (it is in truth more like 1.2, which means there is no climate “emergency”, but let us be generous to the cult).

Eq. (1), informed by these quantities, gives the global warming reduction arising from the drastic emissions reduction caused by the pandemic, on the generous assumption that it is a permanent reduction.

Gee wow golly-gosh! Mirabile dictu!! One whole twenty-fifth of a degree!!! Hold the front page!!!!

All the numbers fed into Eq. (1), as well as the equation itself, are “mainstream science”. And that’s the whole problem with this global warming nonsense. The cost of mitigation is as large as the benefit is small. Even if we stop emitting CO₂ altogether by 2050, if IPCC is right the corresponding small reduction in global temperature will take 125 years to come through.

For that reason alone, even before allowing for official climatology’s glaring error in the definition of temperature feedback, an error in which IPCC intends fraudulently to persist in its Sixth Assessment Report even though it has been told in writing that its definition is incorrect, it makes no economic sense to do anything whatsoever about global warming except to let it happen, adapt to it and enjoy the sunshine.

Will someone tell world followers?

Today’s graphs show a continuing decline in active cases, but the mean daily compound growth rate in cumulative deaths remains high. The reason is that at this stage in the pandemic the case fatality rate is very high. Take the United States.

There have been 66,000 reported deaths at the time of writing, but the Centers for Disease Control concluded a couple of days ago that, based on excess mortality data, deaths have been under-reported by about 15%. So there have really been about 76,000 deaths.

Assuming a mean 17 days from case report to death, the deaths reported now arose on or about April 13, when there were 715,000 cases. So the U.S. case fatality rate, at a rough estimate, is about 10.5%, compared with a global 7.5% (and more like 24% in the UK).

But there are now 1.131 million cases in the United States. Allowing for the current gentle slowing in both reported cases and deaths, even if there were no more cases (and at present there are 30,000 new ones a day), by mid-June and perhaps sooner there will have been 125,000 U.S. deaths associated with the Chinese virus – and counting.

To put this in context, the CDC has estimated that the past winter’s flu season caused somewhere between 20,000 and 62,000 deaths. Already the Chinese-virus deaths have exceeded the high-end estimate within just a few weeks. Unfortunately, there are many more deaths to come.

Fig. 1. Mean compound daily growth rates in estimated active cases of COVID-19 for the world excluding China (red) and for several individual nations averaged over the successive seven-day periods ending on all dates from April 1 to April 30, 2020.

Fig. 2. Mean compound daily growth rates in cumulative COVID-19 deaths for the world excluding China (red) and for several individual nations averaged over the successive seven-day periods ending on all dates from April 8 to April 30, 2020.

Ø High-definition Figures 1 and 2 are here.