The advertising proverb says it all: “The large print giveth, and the small print taketh away.”
Unfortunately, climate science is rife with this. A research announcement is released and the same text appears in media articles everywhere, the only difference being who can attach the scariest headline. One list of things claimed to be caused by global warming numbers 883, including many head scratchers.
For example: species extinctions.
WWF claims “The rapid loss of species we are seeing today is estimated by experts to be between 1,000 and 10,000 times higher than the natural extinction rate. MSNBC laments the “fact” that 100,000 species of flora and fauna will no longer be with us by next Christmas. And yet, WWF also estimates the number of identified unique species to be between 1.4 to 1.8 million, an uncertainty of 400,000. As someone said, “Anytime extinctions are claimed, ask for the names.” The debunking is done in detail here:
On this blog, Science Matters, several posts address specific misleading and exaggerated claims made in the media:
IPCC the Worst Offender
But the IPCC Assessment Reports display the worst abuse of headline claims denied by statements in the details. The headlines are in the Summary for Policy Makers (SPM) while scientists write the details in the Working Group reports, in particular WGII.
We see again a familiar pattern in the latest AR5 round of IPCC releases. As previously, the SPM features alarming statements, which are then second-guessed (undermined) by the actual science imbedded in the report details.
Example Ocean Acidification
For example, I looked at the topic of ocean acidification and fish productivity. The SPM asserts on Page 17 that fish habitats and production will fall and that ocean acidification threatens marine ecosystems.
“Open-ocean net primary production is projected to redistribute and, by 2100, fall globally under all RCP scenarios. Climate change adds to the threats of over-fishing and other non-climatic stressors, thus complicating marine management regimes (high confidence).” Pg 17 SPM
“For medium- to high-emission scenarios (RCP4.5, 6.0, and 8.5), ocean acidification poses substantial risks to marine ecosystems, especially polar ecosystems and coral reefs, associated with impacts on the physiology, behavior, and population dynamics of individual species from phytoplankton to animals (medium to high confidence).” Pg 17 SPM
WGII Report, Chapter 6 covers Ocean Systems. There we find more nuance and objectivity:
“Few field observations conducted in the last decade demonstrate biotic responses attributable to anthropogenic ocean acidification” pg 4
“Due to contradictory observations there is currently uncertainty about the future trends of major upwelling systems and how their drivers (enhanced productivity, acidification, and hypoxia) will shape ecosystem characteristics (low confidence).” Pg 5
“Both acclimatization and adaptation will shift sensitivity thresholds but the capacity and limits of species to acclimatize or adapt remain largely unknown” Pg 23
“Production, growth, and recruitment of most but not all non-calcifying
seaweeds also increased at CO2 levels from 700 to 900 µatm Pg 25
“Contributions of anthropogenic ocean acidification to climate-induced alterations in the field have rarely been established and are limited to observations in individual species” Pg. 27
“To date, very few ecosystem-level changes in the field have been attributed to anthropogenic or local ocean acidification.” Pg 39
Ocean Chemistry on the Record
Contrast the IPCC headlines with the the Senate Testimony of John T. Everett, in which he said:
“There is no reliable observational evidence of negative trends that can be traced definitively to lowered pH of the water. . . Papers that herald findings that show negative impacts need to be dismissed if they used acids rather than CO2 to reduce alkalinity, if they simulated CO2 values beyond triple those of today, while not reporting results at concentrations of half, present, double and triple, or as pointed out in several studies, they did not investigate adaptations over many generations.”
“In the oceans, major climate warming and cooling and pH (ocean pH about 8.1) changes are a fact of life, whether it is over a few years as in an El Niño, over decades as in the Pacific Decadal Oscillation or the North Atlantic Oscillation, or over a few hours as a burst of upwelling (pH about 7.59-7.8) appears or a storm brings acidic rainwater (pH about 4-6) into an estuary.”
Many know of the Latin phrase “caveat emptor,” meaning “Let the buyer beware”.
When it comes to climate science, remember also “caveat lector”–”Let the reader beware”.