Climate Change Weekly # 564—Turns Out Climate Change Isn’t Causing ‘Mass Extinctions’
By The Heartland Institute
One of the persistent claims made across the twentieth century is that humans are causing mass extinction of species, both in rate and numbers, unseen since the end of the age of dinosaurs. I discussed this claim at length and explained why it was not supported by the data and evidence, in my dissertation, “Ecosystemic Goods: The Pros and Cons of a Property Rights Approach.”
More recently, many researchers, green-energy profiteers, green-virtue-signaling politicians, bureaucrats with environment and energy portfolios, and the fawning mainstream media have asserted climate change has replaced other causes as the driving force behind fast-rising extinction rates. The high point of this alarmist rhetoric perhaps was when the misinformed and misguided youth Greta Thunberg was invited to berate the United Nations in a speech made famous on video. Among the many false claims Thunberg made, she said, “People are dying, entire ecosystems are collapsing, we are in the beginning of a mass extinction. . ..” (Emphasis mine. Btw, that portion of the video is used in the opening of The Heartland Institute’s Climate Realism Show each week.)
There is one tiny problem with this claim, as recent research reinforces: It probably just ain’t so!
A study published in October in the Royal Society’s Proceedings B finds that in the past century, amid ongoing climate change, extinction rates have slowed, and they are currently at their lowest in the past 500 years. The findings confirm what I posited in my dissertation: past claims of rapid extinction were based on flawed extrapolations of extinctions on islands to mainland habitats and ecosystems. Island biogeography studies have never been a solid basis for projecting mainland extinctions nor of the types of species threatened.
From the article abstract (emphasis mine):
Biodiversity loss is one of the greatest challenges facing Earth today. The most direct information on species losses comes from recent extinctions. However, our understanding of these recent, human-related extinctions is incomplete across life, especially their causes and their rates and patterns among clades, across habitats and over time. Furthermore, prominent studies have extrapolated from these extinctions to suggest a current mass extinction event. Such extrapolations assume that recent extinctions predict current extinction risk and are homogeneous among groups, over time and among environments. Here, we analyse rates and patterns of recent extinctions (last 500 years). Surprisingly, past extinctions did not strongly predict current risk among groups. Extinctions varied strongly among groups, and were most frequent among molluscs and some tetrapods, and relatively rare in plants and arthropods. Extinction rates have increased over the last five centuries, but generally declined in the last 100 years. Recent extinctions were predominantly on islands, whereas the majority of non-island extinctions were in freshwater. Island extinctions were most frequently related to invasive species, but habitat loss was the most important cause (and current threat) in continental regions. Overall, we identify the major patterns in recent extinctions but caution against extrapolating them into the future.
A number of species lost to extinction over the past 500 years were the result of commercial hunting for meat, hides, and feathers. However, most species then, and as it seems is the case still, have been lost to the introduction of invasive species and, most importantly, habitat loss from conversion of wildlands for agriculture, dams, urban development, and other types of anthropogenic land alterations.
“For their study, [Kristen] Saban and [John] Wiens analyzed rates and patterns of recent extinctions, specifically across 912 species of plants and animals that went extinct over the past 500 years,” wrote my Heartland Institute colleague Anthony Watts in describing the study. “All in all, data from almost 2 million species were included in the analysis.”
The good news is that extinctions of plants, arthropods, and land vertebrates peaked about 100 years ago and have declined since then, even as the climate has changed.
Directly addressing this point in a University of Arizona interview, Wiens said, “We show that extinction rates are not getting faster towards the present, as many people claim, but instead peaked many decades ago.”
So much for climate change driving the sixth great mass extinction. If this study is correct, climate alarmists will have to drop this talking point from their litany of climate horrors.
Sources: Proceedings B of The Royal Society; Watts Up With That
