Debunking The Utterly Unscientific 1.5°C Climate Cliff

Reason magazine recently posted an article on its website titled “There Is No 1.5°C Climate Cliff,” arguing that the 1.5°C threshold touted by the United Nations Intergovernmental Panel on Climate Change, world governments, and activists, is not based on any scientific investigation, but is rather arbitrary.

This is true. [emphasis, links added]

The threshold value was first developed by a panel of advisors who had no data to show that 1.5° warming would be catastrophic, and the language used by the media has only become more extreme since then.

In the post, writer Ronald Bailey explains that the 1.5°C threshold was developed in the 1990s by the German Advisory Council on Global Change.

Bailey writes:

The advisors adopted two principles to guide their work. The first was the “preservation of Creation in its present form” achieved chiefly by staying within their guess of what would be “a tolerable ‘temperature window.’’’ The second was the “prevention of excessive costs.” Their analysis of what would constitute a tolerable temperature window occupies a single paragraph.

There they reckoned that the mean maximum temperature during the last interglacial period was 16.1 C to which they arbitrarily added a further 0.5 C to establish tolerable maximum temperature of 16.6 C.

They then assumed that in 1995 the current global mean temperature was around 15.3 C which would be only 1.3 C below their tolerable maximum. Finally, they presupposed the 1995 average was 0.7 C above the preindustrial average which yields an overall 2.0 C threshold.

This was not a rigorous scientific investigation.

Climate Realism has explained this fact in past posts as well, such as here, here, and here, where we point out that there is also no evidence to suggest passing that arbitrary warming threshold would cause “climate chaos” or positive-feedback type cascading events.

Climate at a Glance: Tipping Points concurs, showing that there is no evidence that irreversible tipping points exist at all.

Since the conception of the threshold, only computer models with faulty assumptions built in have driven the alarmist claims and associated headlines tied to the 1.5C figure.

It is also possible that the 1.5°C threshold has already been passed.

Meteorologist Anthony Watts explains in “Media Regurgitates IPCC’s ‘Final Warning’ on Climate Change – Without Realizing We’ve Already Passed 1.5°C,” Berkeley Earth’s global surface temperature data show that the planet may have warmed a full 4°C since 1750.

Despite this, no catastrophes have occurred, and extreme weather has not become worse since that period.

Bailey writes “It is good, although not surprising, news that when the world passes through the 1.5 C target, it will not be plunging to its death over a climate cliff.”

He is correct, and what’s more, some climate scientists and media have been cautioning against making claims that make 1.5°C sound like an existential threat.

The fact is, if it has not been passed already as discussed above, the threshold is going to be passed soon, even if immense fossil fuel cuts are made.

When disasters don’t materialize, climate scientists who previously hyped the 1.5 C threshold as a catastrophic tipping point will, or at least should, lose credibility.

Reason and Ronald Bailey should be applauded for publishing such a detailed and thorough investigation of the origin and lack of scientific basis for the popular global warming threshold.

[No evidence supports] the idea that 1.5°C warming will be a dangerous “climate cliff” that will cause more chaotic weather.

Top photo by Mika Baumeister on Unsplash

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