SUMMARY:
"The results of this analysis were stunning", lead author Hillebrand says.
The vast majority of the 36 meta-analyses found that the strength of pressure affected the response magnitude, but only very few (3 out of 36) showed statistical evidence for any kind of threshold, or tipping point. Hillebrand points out:
"The thresholds are either truly absent or they exist but they remain undetectable by our statistical approach".
According to lead author Hillebrand,
"If scientists cannot measure how close a certain ecosystem is to a threshold inducing a tipping point, how useful can then a regulation or policy be relying on such a threshold?"
In addition, by focusing on imaginary tipping points, scientists and policy makers (politicians and government bureaucrats) may risk overlooking the impacts, negative or positive, from gradual changes to ecosystems.
DETAILS:
Most policies concerning global environmental change rely on the concept of tipping points. For example, if the global average temperature changes by some imaginary amount, past a fictional tipping point. it would become impossible to prevent a climate crisis. That crisis has been predicted for 50 years, so many people are "sure" it is coming! But we are "safe" below the imaginary tipping point. In fact, tipping points are nonsense, intended for political gain, not the result of real science.
An international team of scientists, led by biodiversity expert Prof. Dr. Helmut Hillebrand, of the University of Oldenburg in Germany, is now questioning whether the tipping point concept is suited for developing environmental policies. Using detailed statistical analyses of published results, from more than 4,600 field experiments, the scientists found little evidence for tipping points, or thresholds.
The analysis has been published in the Journal Nature Ecology and Evolution. Their results certainly should be true for air pollution, water pollution and soil pollution. But not for the beneficial global warming we have been having since the late 1600s.
Adding CO2 to the atmosphere is beneficial for green plants. Smart greenhouse owners use CO2 enrichment systems inside their greenhouses for the same reason. And if that added CO2 also causes global warming, which is an assumption, not a proven fact, the actual warming in the past 45 years, since 1975, has been good news. Mainly in colder regions, blessed mainly with nights that are not as cold as before, mainly during the six coldest months of the year.
Many ecological "case studies" have been published that claim "tipping points" of ecosystems. So policy makers ($#@&% politicians and government bureaucrats) rely on tipping points to draft laws and agency rules. Does that make sense? This study says no.
Study scientists used experimental data derived from already published synthesis efforts - so-called meta-analyses. "This is a statistical method ecologists apply to summarize the general outcome of many field experiments", explains Dr. Hillebrand, who is an expert in synthesis efforts.
Study authors used information from 36 meta-analyses, which cover 4,601 unique field experiments on natural or close-to-natural ecological communities.
This is the largest effort ever synthesizing scientific literature on global change, according to the authors.
The researchers devised statistical tools that allowed them to test whether the magnitude of response related to the strength of pressure. A very common "pressure" in studies summarized on this blog is plant growth with higher CO2 levels. Co-author Dr. Jan Freund is a modeling expert at the Institute for Chemistry and Biology of the Marine Environment, at the University of Oldenburg