Carbon Dioxide Causes Much Less Warming Than is Commonly Believed, New Paper Finds

Further holes have been blown in the ‘settled’ scientific view that humans are responsible for all or most of the changes in the climate by burning hydrocarbons. Three scientists, including Atmospheric Professor Yi Huang of McGill University, have reduced by nearly 40% the basic amount of warming caused by a doubling of atmospheric carbon dioxide – a figure commonly used to promote the global warming scare. In addition they cast doubt on the ability of CO₂ to heat the atmosphere beyond the levels already passed in the pre-industrial age. “Transmissivity in the CO₂ band centre is unchanged by increased CO₂ as the absorption is already saturated,” they note.

If correct, of course, this work destroys the ‘settled’ climate science that back the collectivist Net Zero project. The findings are likely to be ignored by the mainstream media. Indeed, on past form some activist journalists and scientists may seek to get the paper retracted. For the time being, it is published by the American Meteorological Society in its Journal of Climate.

Another sensational finding is that higher levels of CO₂ seem to actually cool Antarctica. “The [doubled CO₂] forcing in polar regions is strongly hemispheric asymmetric and is negative in the Antarctic,” write the scientists. None of this will be a surprise to regular readers since it would appear to be confirmed by observations that the region has shown “nearly non-existent warming” over the last 70 years. The recent “mind-blowing’” scare over low levels of winter sea ice has been debunked by evidence from early weather satellites showing similar levels in 1966.

The main paper is behind a paywall but an excellent summary of its contents is provided by the science blog No Tricks Zone. The science is complex with the ‘Abstract’ explaining that the paper evaluates the “spatiotemporal variation of the instantaneous, longwave CO₂ radiative forcing at both the TOA [top of the atmosphere] and surface”. In plain terms, the work investigates the rise in temperature at three levels in the atmosphere as the Earth adjusts its thermal balance from heat trapped by so-called ‘greenhouse’ gases. Using a watts per square metre formulation (3.7 W/m²), it is commonly held by the Intergovernmental Panel on Climate Change that a doubling of CO₂ will lead to a rise in temperature at the TOA of 1.2°C. The scientists have reduced this number to 2.26 W/m², a 39% reduction down to a temperature rise of 0.72°C. At the surface, the rise is only 0.55°C. Large parts of the globe are measured at 0 W/m² including below zero for Antarctica.

The inconvenient idea that CO₂ ‘saturates’ above certain atmospheric levels, possibly at levels lower than current concentrations, has long been dismissed, but it does have the advantage of explaining the higher gas levels seen in the past. Carbon dioxide only absorbs heat in narrow bands on the infrared spectrum and it commonly overlaps with other warming gases such as ubiquitous water vapour. “The water vapour and CO₂ overlapping at an absorbing band prevents absorption by additional CO₂,” observe the authors. The water vapour usually damps the doubled CO₂ forcing by reducing the energy additional CO₂ can absorb, they add.

The W/m² figure is a vital building block in attempts to put a figure on the final temperature rise caused by a doubling of CO₂, a process known as climate sensitivity. Scientists also point to other influences, or forcings, on climate and these include feedback from many sources such as evaporation, ice albedo (reflection) and clouds. For a ‘settled’ scientific narrative, it is remarkably little understood how such feedback actually happens. In fact, it is probably beyond accurate measurement in a chaotic, non-linear atmosphere. The results of climate models over 40 years would appear to confirm that last statement.

None of this has stopped activist scientists claiming double CO₂ warming between 2-6°C. It is essentially a made-up figure often called an hypothesis – science-speak for an opinion. Despite claims it cannot be ‘denied’, it is not a ‘theory’ or a ‘law’. It is an opinion that has remained unproven for over 50 years. Not a single science paper can tell us what the climate sensitivity figure is – activists are free to speculate that temperatures will rise by up to 6°C, but others suggest it is well below 1°C and indistinguishable from natural climate variation. Despite all this, a majority of science papers preach climate doomsday scenarios using RCP 8.5 ‘pathway’ modelled data that suggests the global temperature will rise by up to 4°C within less than 80 years. Other activists use computer models to claim that they can attribute single bad weather events to long-term changes in the climate.

All of this is pseudoscience since it’s non-falsifiable and hence doesn’t meet the test of a scientific hypothesis. It is however the lynchpin of the argument that there’s no point in debating climate science and all heretics should be silenced in the interest of drastic Net Zero-inspired economic and societal control.

Chris Morrison is the Daily Sceptic’s Environment Editor.