by Larry Kummer

The Extinction Rebellion and the Green New Deal arouse fears of extinction for other species, and humanity. Only the complicit silence of climate scientists makes this possible. Compare the alarmists’ claims with what scientists said in the IPCC’s Fifth Assessment Report (AR5). Too bad that journalists don’t.

Climate hysteria goes mainstream. Climate scientists are silent.

The Extinction Rebellion – “Life on Earth is in crisis: scientists agree we have entered a period of abrupt climate breakdown, and we are in the midst of a mass extinction of our own making. …see how we are heading for extinction.” See their evidence here.

“If Politicians Can’t Face Climate Change, Extinction Rebellion Will” by David Graeber (prof anthropology at the LSE) in a NYT op-ed – “A new movement is demanding solutions. They may just be in time to save the planet.” Also see “Extinction Rebellion and Momentum join forces on climate crisis” by Martha Busby at The Guardian.

Rep. Alexandria Ocasio-Cortez (D-NY) is interviewed by Ta-Nehisi Coates at an “MLK Now” event in New York. Video here.

“Millennials and people, you know, Gen Z and all these folks that will come after us are looking up and we’re like: ‘The world is gonna end in 12 years if we don’t address climate change and your biggest issue is how are we gonna pay for it?’”

“Planet Earth Is Doomed. How Do I Go On?” by Liza Featherstone at The Nation.

“Andrew Samuels, a Jungian psychoanalyst and a professor at the University of Essex, tells me that therapists are increasingly hearing from patients who are deeply disturbed by climate change and are struggling to cope.”

“We Need Radical Thinking on Climate Change” by Kevin Drum at Mother Jones – “{The Green New Deal} would only change the dates for planetary suicide by a decade or so.”

“The Uninhabitable Earth” by David Wallace-Wells in New York Magazine – “Famine, economic collapse, a sun that cooks us: what climate change could wreak – sooner than you think.” Expanded into a book: The Uninhabitable Earth: Life After Warming .

“The five ways the human race could be WIPED OUT because of global warming.” By Rod Ardehali at the Daily Mail. H/t to the daily links at Naked Capitalism. Promo for Falter: Has the Human Game Begun to Play Itself Out? , a book by Bill McKibben.

The media overflows with credulous stories about this hysteria. It must be having a bad effect on America. Activist Naomi Klein wants journalists to deliver even more alarmism and less science. There is almost no basis for these fears.

First fruits of the Extinction Rebellion’s climate hysteria: the UK parliament declares a “Climate Emergency.” Some say this puts the UK on a “war footing”, always a useful way to increase a government’s power over its people.

About the coming extinctions!

What does the IPCC Working Group II of AR5 say about extinctions? Its Summary for Policymakers gives a bold warning.

“Extinction risk is increased under all RCP scenarios, with risk increasing with both magnitude and rate of climate change.”

That is politics, meaningless rhetoric, not science. It tells us nothing about timing and magnitudes of changes compared to temperature increases. Turn to the full report for answers. First, the good news – they give a rebuttal to the hysteria about the mass extinctions supposedly occurring now due to climate change (more details here).

“{O}nly a few recent species extinctions have been attributed as yet to climate change (high confidence) …” {p4.}

“While recent climate change contributed to the extinction of some species of Central American amphibians (medium confidence), most recent observed terrestrial species extinctions have not been attributed to climate change (high confidence).” {p44.}

“Overall, there is very low confidence that observed species extinctions can be attributed to recent climate warming, owing to the very low fraction of global extinctions that have been ascribed to climate change and tenuous nature of most attributions. (p300.)

Looking to the future.

Much of the report discusses possible results of 4°C warming above preindustrial levels – as of 2018, we are now ~1°C above preindustrial (likely 0.8 – 1.2°C). Supposedly a raise of over 0.5°C will prove disastrous (i.e., over the 1.5°C red line). A further increase of 3°C is wildly improbable by 2065 (the visibility limit of reliable forecasting), and unlikely even by 2100 (i.e., that is in the middle of the range for the improbable RCP8.5 scenario).

WGI used a recent baseline for temperature comparisons: the average of 1986–2005. WGII measured from preindustrial temperatures, defined as before 1750 (WGI occasionally uses preindustrial, such as for historical analysis). Comparing with preindustrial has advantages for climate alarmists.

It measures warming from close to the trough of the coolest period for thousands of years.

There is no instrumental record for global temperatures in 1750.

Most valuable, it allows conflating the natural warming from 1750 to WWII with the mostly anthropogenic warming (AGW) since WWII. So, to the public, all ill effects of this warming become effects of AGW.

What does WGII say about extinctions resulting from AGW? They give many scary findings. But, like the headline conclusion given above, most either lack meaningful details, or are given low confidence, or both.

“Models project that the risk of species extinctions will increase in the future due to climate change, but there is low agreement concerning the fraction of species at increased risk, the regional and taxonomic distribution of such extinctions, and the timeframe over which extinctions could occur.” {p67.}

“Within this century, magnitudes and rates of climate change associated with medium- to high-emission scenarios (RCP4.5, 6.0, and 8.5) pose high risk of abrupt and irreversible regional-scale change in the composition, structure, and function of terrestrial and freshwater ecosystems, including wetlands (medium confidence).” (p15.)

“From a global perspective, open ocean NPP {net primary productivity} will decrease moderately by 2100 under both low- (SRES B1 or RCP4.5) and high-emission scenarios (medium confidence; SRES A2 or RCPs 6.0, 8.5) …. However, there is limited evidence and low agreement on the direction, magnitude and differences of a change of NPP in various ocean regions and coastal waters projected by 2100 (low confidence).” (p135.)

“There is a high risk that the large magnitudes and high rates of climate change associated with low-mitigation climate scenarios (RCP4.5 and higher) will result within this century in abrupt and irreversible regional-scale change in the composition, structure, and function of terrestrial and freshwater ecosystems, for example in the Amazon (low confidence) and Arctic (medium confidence), leading to substantial additional climate change.” (p276.)

WGII discusses bad impacts on some specific kinds of creatures, such as corals. Nothing about extinction of humans. The 1,150 pages of WGII have a remarkable lack of specificity about what we can expect from the various scenarios. There is one exception, a paper that WGII cites 22 times. It was published ten years ago, with no mention of its replication or follow-up research. This is an example of what Andrew Revkin condemns as the “single study syndrome” (e.g., here and here).

“Fischlin et al. (2007) found that 20 to 30% of the plant and animal species that had been assessed to that time were considered to be at increased risk of extinction if the global average temperature increase exceeds 2°C to 3°C above the preindustrial level with medium confidence, and that substantial changes in structure and functioning of terrestrial, marine, and other aquatic ecosystems are very likely under that degree of warming and associated atmospheric CO2 concentration. No time scale was associated with these findings.” (p278.)

“All model-based analyses since AR4 broadly confirm this concern, leading to high confidence that climate change will contribute to increased extinction risk for terrestrial and freshwater species over the coming century. Most studies indicate that extinction risk rises rapidly with increasing levels of climate change, but some do not. …There is, however, low agreement concerning the overall fraction of species at risk, the taxa and places most at risk, and the time scale for climate change-driven extinctions to occur.” (p300.)

AR5 describes the assessed likelihood of an outcome or a result: “virtually certain 99–100% probability, very likely 90–100%, likely 66–100%, about as likely as not 33–66%, unlikely 0–33%, very unlikely 0–10%, exceptionally unlikely 0–1%.”

Conclusions

The Left has incited hysteria about climate change for political gain (the Green New Deal is their maximum dreams given form). Their claims go far beyond consensus climate science, with little basis in the IPCC assessments. Climate scientists and their institutions have remained silent for years as the Left’s claims grew more extreme and less grounded in science. Turning these issues into an irrational crusade makes rational public policy far more difficult to achieve.

An ignored warning from 2010, a path not taken

Here is a remarkable op-ed in the BBC: “Science must end climate confusion” by climate scientist Richard Betts, 11 January 2010. He cautions about scientists exaggerating or misrepresenting climate science “if it helps make the news or generate support for their political or business agenda.”

Too bad climate scientists did not heed his warning.

Originally posted at Fabius Maximus.

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