Greenpeace says 95% certainty is the same as 100% certainty. Tell that to people who die on the operating table.

click to read the full Greenpeace blog post

When the Intergovernmental Panel on Climate Change (IPCC) held its recent press conference in Stockholm, I was monitoring the online reaction.

In no time at all, activist organizations were making public statements in response. Greenpeace unleashed a press release that began with two words: “Greenpeace demands…” It talked about “climate chaos,” tipping points, and stoking “the fires of climate change by burning fossil fuels.”

Stephanie Tunmore, a Greenpeace International climate campaigner, discussed the “strongest take away from this report” – even though the report itself hadn’t yet been released.

For good measure, Tunmore followed up with a blog post that same day in which she claimed that IPCC personnel are the “world’s top climate scientists” and that the IPCC is the “world’s leading authority on the science of climate change.” She then proceeded to ignore what the IPCC actually said.

In the entirely subjective opinion of a particular group of IPCC authors, it’s “extremely likely” (95% certain) that “more than half of the observed increase in global average surface temperature from 1951 to 2010” was caused by human-generated greenhouse gas emissions (see the bottom of p. 13 here).

Judith Curry discusses that opinion near the bottom of this blog post. These remarks, in particular, are entertaining:

The 95% is basically expert judgment, it is a negotiated figure among the authors. The increase from 90-95% means that they are more certain. How they can justify this is beyond me. [bold added]

In other words, a reputable climate scientist thinks the IPCC displayed poor judgment when it chose to raise its certainty level from 90 to 95%. Yet Greenpeace is prepared to push the envelope even further. In Tunmore’s words:

It is now certain that most of the warming since 1951 was caused by human activities. [bold added]

Pardon? Only in an activist fantasy world does “extremely likely” translate as “certain.” If there’s a five percent chance that I’m wrong about something, it is not a certainty.

click to read the full Greenpeace blog post

Global warming activists love medical analogies, so let’s use one of our own. According to recent research, your chance of dying after receiving surgery-related general anesthetic is approximately 34 out of one million (see here and here). That’s 0.0034% – or three one-thousands of a percent.

Yet, prior to surgery, medical personnel are still obligated to warn you that there’s a risk. They aren’t allowed to brush aside that tiny number and declare that there’s nothing to worry about.

If an outcome isn’t certain when there’s only a 0.0034% chance of something going wrong, it is by no means certain that humanity is responsible for most of the recent warming. The IPCC itself admits there’s a full 5% chance it might be mistaken.

While Greenpeace claims to recognize the authority of the IPCC, it isn’t actually interested in – and has no respect for – this body’s findings. The IPCC’s new report is a prop, nothing more, in the Greenpeace drama.

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The Greenpeace press release is backed up here. Tunmore’s blog post is backed up here.

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