The Royal Society has produced a new report to try to maintain the climate scare, providing an update on the last IPCC report (AR5) that came out in 2013. Unsurprisingly, the main message is “it’s worse then we thought”.
It’s in two parts, a document that summarises their main points in a non-technical way, starting off with “Climate change is one of the defining issues of our time” and a supporting document that includes references to new papers published since AR5. Unsurprisingly, the main message is “it’s worse then we thought”. The authors include several of the familiar “usual suspects” with a solid track record in alarmism and exaggeration, such as Joanna Haigh, Ed Hawkins, Gabriele Hegerl and Brian Hoskins.
The report addresses 13 questions, some of which we have looked into, see below.
Climate Sensitivity (Paul)
The first question explored is How sensitive is global temperature to increasing greenhouse gases?
The summary claims that:
In 2013, the IPCC report stated that a doubling of pre-industrial carbon dioxide concentrations would likely produce a long-term warming effect of 1.5 to 4.5°C; the lowest end of that range now seems less likely.
The article explains what climate sensitivity is, and discusses the different ways of trying to estimate it. It points out that there tends to be a difference between estimates that are based on observations, and estimates that are based on computer models (see if you can guess which method gives the higher values – observations or computer models).
This figure is included, which shows a comparison of observations with models assuming an ECS of 2.1C, 2.8C and 3.7C.
Notice that the observations curve lies below all three of these, suggesting that the climate sensitivity is below 2.1C. Yet the Royal Society document claims that lower values of ECS are less likely. So the report has included a diagram that shows the opposite of what is claimed. Maybe it’s a typo, and the statement should have read “the highest end of that range now seems less likely” (unfortunately not — the section ends with a statement that values below 2C now seem less plausible).
Several recent papers are included in the reference list that look at the question of climate sensitivity.
Recent attempts to diagnose equilibrium climate sensitivity (ECS) from changes in Earth’s energy budget point toward values at the low end of the Intergovernmental Panel on Climate Change Fifth Assessment Report (AR5)’s likely range (1.5–4.5 K).
Again, this is the opposite of what is claimed in the RS report.