The unspoken truth in the supposedly ‘settled’ world of climate science is that after decades of research costing billions of dollars we are no nearer knowing how much global temperatures will rise in response to increasing atmospheric carbon dioxide levels. In fact, notes Dr. Roy Spencer, the latest crop of climate models, known as CMIP6, now disagree on the expected amount of warming in the lower atmosphere “more than ever before”.
Estimates currently vary between 1.8°C to 5.6°C among researchers who run computer models and mostly believe the rises are caused by humans burning fossil fuel. But as Daily Sceptic readers have seen, this hypothesis is not the only game in town. It is known that greenhouse gases such as CO2 only trap heat within narrow bands of the infrared spectrum. Some scientists suggest the gases become ‘saturated’ and their warming effect falls sharply as concentrations rise, declining after a certain point on a logarithmic scale. To understand this in simple terms, it can be noted that doubling loft insulation in a house will not trap twice as much heat, since most of it has already been enclosed.
Dr. Spencer, who is a Principal Research Scientist at the University of Alabama in Huntsville (UAH), argues that the wide margin of temperature prediction occurs because the role of clouds and water vapour (the most abundant greenhouse gas) are “insufficiently understood”. The former NASA scientist and compiler of the accurate UAH global temperature record feels the models are not yet up to the task since they now disagree with each other “by a factor of three or more”.
Huntsville, we have a problem. Global elites are forcing their populations to undergo radical economic and societal transformations through the imposition of a collectivist Net Zero project by promoting a ‘settled’ science narrative that says humans control the climate. Climate Armageddon tales are spun from UN platforms through to mainstream media headlines stating the temperature will soar unless fossil fuel, currently supplying 80% of our energy needs, is removed within less than 30 years. But it all rests on an unproven hypothesis that cannot count a single peer-reviewed paper that provides conclusive proof that humans cause all or most climate change. The advantage of the rival saturation hypothesis is that it fits past observations of climate, given that CO2 levels have been up to 20 times higher without any sign of runaway global heating. After 50 years of work, scientists are no nearer agreeing on the crucial issue at the heart of the climate debate. How much will the temperature rise if more CO2 enters the atmosphere? The ‘science’ is settled only within the ranks of the politically committed.
The gulf in understanding about the projected temperature rise is shown in the graph below. Equilibrium Climate Sensitivity (ECS) is the estimated rise in temperature if C02 doubles in the atmosphere. It is widely quoted. Transient Climate Response (TCR) is a measure estimating warming when CO2 rises at 1% a year.
It can be seen that the modelled ECS range (orange bar) of 1.8C to 5.6C in the latest CMIP6 is the largest of any generation of models dating back to the1990s. The graph was produced in a 2020 paper analysing ECS and TCR led by the IPCC author Gerald Meehl. Like Spencer, the authors found that cloud feedbacks were the “most likely” contributors to the high values and increased range of ECS in the latest models. It is noted that early “simple” models from the 1970s produced warming between 1.5C-4-5C. This simplistic view of the response of earth climate systems was viewed at the time as “informing the magnitude” of the relative climate change the Earth could experience in the future.
And does to this day, after decades of growing green hysteria and scientific work that has actually widened this corridor of great uncertainty.
In fact the Meehl paper gives an idea of how little scientists still understand about the chaotic and non-linear atmosphere. Certain processes connected to ocean heat uptake would be better quantified by “improved temperature observations through the full depth of the global ocean, as well as increased understanding of various feedbacks in the climate system”, it is noted. Making progress will also require “enhanced observations” that could provide “new insight into cloud microphysics”.
The Meehl paper accepts that the situation has “elicited scrutiny” because there are implications for “policy-relevant mitigation strategies”. But any scrutiny of climate models is lacking in the wider political and media debate. As with Covid, the results of models are accepted almost without question in the rush to Net Zero, despite, for instance, 40 years of wrong temperature forecasts. In addition, scientists model climate impacts using improbable pathways assuming warming of up to 5C in less than 80 years. As the recent Clintel report showed, almost half of the climate impacts forecast by the IPCC and the wider scientific community are based on this highly improbable data. Meanwhile, so called eco anxiety rises as mainstream media acts as an uncritical trusted messenger for all the doom-laden predictions.
Chris Morrison is the Daily Sceptic’s Environment Editor.