Summary: The IPCC’s Special Report “Global Warming of 1.5°C” is cited as the basis for climate activists’ predictions of doom. Look at the report. There is nothing in it justifying such apocalyptic forecasts.
“Global Warming of 1.5°C“
An IPCC Special Report, 6 October 2018.
Excerpt from the Summary for Policymakers. Red emphasis added.
B1. Climate models project robust differences in regional climate characteristics between present-day and global warming of 1.5°C, and between 1.5°C and 2°C. …
B1.1. Evidence from attributed changes in some climate and weather extremes for a global warming of about 0.5°C supports the assessment that an additional 0.5°C of warming compared to present is associated with further detectable changes in these extremes (medium confidence). …
B1.3. Risks from droughts and precipitation deficits are projected to be higher at 2°C compared to 1.5°C global warming in some regions (medium confidence). …
B2. By 2100, global mean sea level rise is projected to be around 0.1 metre lower {4″} with global warming of 1.5°C compared to 2°C (medium confidence). …
B2.1. Model-based projections of global mean sea level rise (relative to 1986-2005) suggest an indicative range of 0.26 to 0.77 m by 2100 for 1.5°C global warming, 0.1 m (0.04-0.16 m) {4″} less than for a global warming of 2°C (medium confidence). …
B3. On land, impacts on biodiversity and ecosystems, including species loss and extinction, are projected to be lower at 1.5°C of global warming compared to 2°C. …
B3.1. Of 105,000 species studied,9 6% of insects, 8% of plants and 4% of vertebrates are projected to lose over half of their climatically determined geographic range for global warming of 1.5°C, compared with 18% of insects, 16% of plants and 8% of vertebrates for global warming of 2°C (medium confidence). …
B3.2. Approximately 4% (interquartile range 2–7%) of the global terrestrial land area is projected to undergo a transformation of ecosystems from one type to another at 1ºC of global warming, compared with 13% (interquartile range 8–20%) at 2°C (medium confidence). …
B4. Limiting global warming to 1.5°C compared to 2ºC is projected to reduce increases in
ocean temperature as well as associated increases in ocean acidity and decreases in ocean
oxygen levels (high confidence). …
B4.1. There is high confidence that the probability of a sea-ice-free Arctic Ocean during summer is substantially lower at global warming of 1.5°C when compared to 2°C. With 1.5°C of global warming, one sea ice-free Arctic summer is projected per century. This likelihood is increased to at least one per decade with 2°C global warming. Effects of a temperature overshoot are reversible for Arctic sea ice cover on decadal time scales (high confidence). …
B4.4. Impacts of climate change in the ocean are increasing risks to fisheries and aquaculture via impacts on the physiology, survivorship, habitat, reproduction, disease incidence, and risk of invasive species (medium confidence) but are projected to be less at 1.5ºC of global warming than at 2ºC.
————– There are 4 more pages like this. ————–
Summary of the SPM
Most of the findings in the SPM of this Special Report are of two kinds. First, stating that the effects of 1.5°C warming are less than those of 2.0°C warming. Pretty obvious, but it means little unless we know the effects of 2°C warming. It seldom quantifies the difference in effects from that extra 0.5°C warming, which is the key information necessary to know when assessing the cost-benefit of limiting the coming warming.
Second, there are more specific findings given at a “medium” level of confidence. The IPCC uses five levels of confidence: very low, low, medium, high, and very high. “Medium” is a weak basis for extreme measures to restructure society and the global economy. Especially since it is human nature to overestimate confidence more often than to underestimate it.
There is nothing in this Special Report justifying belief that the world will end, that the world will burn, or that humanity will go extinct. The disasters described the Climate Emergency and Extinction Rebellion activists are those of RCP8.5, the worst-case scenario in the IPCC’s Fifth Assessment report – or even beyond it. RCP8.5 is, as a worst-case scenario should be, a horrific but not apocalyptic future that is improbable or impossible.
The hysteria of activists
In the past year, climate activists have gone full doomster – with predictions of disasters up through an apocalypse, often citing the SR1.5. It has swept the West like the 1918 flu. As in this graphic, pinned to the Twitter page of Julia K. Steinberger, Professor of Social Ecology & Ecological Economics at the University of Leeds. It is from her article at Medium about saving the world.
Some climate scientists I have spoken with dismiss the hysterical claims of climate activists. That is a mistake. The effectiveness of propaganda is unrelated to its accuracy. It just has to tell a compelling story.
“Do remember you are there to fuddle him. From the way some of you young fiends talk, anyone would suppose it was our job to teach!
— Advice from Screwtape to his nephew, from chapter I of The Screwtape Letters by C. S. Lewis (1942).
For years, RCP8.5 provided the material for an almost endless series of stories to scare the public (see examples) about the horrible future ahead if we did not change the world. But eventually people pointed out that RCP8.5 was either extremely improbable or impossible (see here and here). Scientists began considering less extreme scenarios. The entire doomster program was at risk. But there was a backup plan.
The 2°C warming target was set somewhat randomly (see here and here). It was the basis for the Paris Agreement(implemented by Obama without Senate approval). It proved a weak tool for activists. So the target was lowered to 1.5°C, which would require massive changes.
About the SR15 report
For a report of this important, it has received surprisingly little critical analysis. One of the few is “Deficiencies In the IPCC’s Special Report on 1.5 Degrees” by climate scientist J. Ray Bates. He documents two weaknesses in SR15.
- “It departs from the IPCC (2013) Fifth Assessment in the direction of an increased sense of planetary emergency without giving rigorous scientific reasons for doing so.
- “Crucial research evidence, accumulated since the IPCC Fifth Assessment (2013), significantly reduces the prospect of a looming emergency. This evidence has not been taken into account; nor is it even referred to in the SR1.5 report.”
Read the report and decide for yourself.