By Cliff Montgomery – June 25th, 2015
“Our global society has started to destroy species of other organisms at an accelerating rate,” thus “initiating a mass extinction episode unparalleled for 65 million years,” according to an eye-opening report released last week by the American Association for the Advancement of Science (AAAS).
“The loss of bio-diversity is one of the most critical current environmental problems, threatening valuable ecosystem services and human well-being,” stated the study.
“The average rate of vertebrate species loss over the last century is up to 114 times higher than the background rate,” declared the AAAS, which added that these species should “have taken, depending on the vertebrate taxon, between 800 and 10,000 years to disappear.”
These findings are based on “conservative comparisons with modern extinctions,” emphasized the report.
AAAS points out that “averting a dramatic decay of bio-diversity and the subsequent loss of ecosystem services is still possible through intensified conservation efforts,” but adds that the “window of opportunity is rapidly closing.”
Below, offers a number of quotes from the study:
“Arguably the most serious aspect of the environmental crisis is the loss of bio-diversity—the other living things with which we share Earth. This affects human well-being by interfering with crucial ecosystem services such as crop pollination and water purification and by destroying humanity’s beautiful, fascinating, and culturally important living companions.
“Our analysis shows that current extinction rates vastly exceed natural average background rates, even when (i) the background rate is considered to be double previous estimates and when (ii) data on modern vertebrate extinctions are treated in the most conservative plausible way.
“We emphasize that our calculations very likely under-estimate the severity of the extinction crisis because our aim was to place a realistic ‘lower bound’ on humanity’s impact on bio-diversity.
“Therefore, although biologists cannot say precisely how many species there are, or exactly how many have gone extinct in any time interval, we can confidently conclude that modern extinction rates are exceptionally high, that they are increasing, and that they suggest a mass extinction under way—the sixth of its kind in Earth’s 4.5 billion years of history.
“A final important point is that we focus exclusively on species, ignoring the extirpation of populations—the units relevant to ecological functioning and the delivery of ecosystem services.
“Population extinction cannot be reliably assessed from the fossil record, precluding any analysis along the lines of that presented here. Also, although it is clear that there are high rates of population extinction, existing data are much less reliable and far harder to obtain than those for species, which will remain true for the foreseeable future.
“Likewise, we have not considered animals other than vertebrates because of data deficiencies.
“The evidence is incontrovertible that recent extinction rates are unprecedented in human history and highly unusual in Earth’s history.
“Our analysis emphasizes that our global society has started to destroy species of other organisms at an accelerating rate, initiating a mass extinction episode unparalleled for 65 million years.
“If the currently elevated extinction pace is allowed to continue, humans will soon (in as little as three human lifetimes) be deprived of many bio-diversity benefits.
“On human time scales, this loss would be effectively permanent because in the aftermath of past mass extinctions, the living world took hundreds of thousands to millions of years to re-diversify.
“Avoiding a true sixth mass extinction will require rapid, greatly intensified efforts to conserve already threatened species and to alleviate pressures on their populations—notably habitat loss, over-exploitation for economic gain, and climate change.
“All of these are related to human population size and growth, which increases consumption (especially among the rich), and economic inequity.
“However, the window of opportunity is rapidly closing.”
