This is the time of year when pop science news recycles all the leftovers left over all over again, and this one was bound to come up—left over again:
From ScienceDaily:
Early humans were the dominant cause of the extinction of a variety of species of giant beasts, new research has revealed.
The researchers ran thousands of scenarios which mapped the windows of time in which each species is known to have become extinct, and humans are known to have arrived on different continents or islands. This was compared against climate reconstructions for the last 90,000 years.
Examining different regions of the world across these scenarios, they found coincidences of human spread and species extinction which illustrate that man was the main agent causing the demise, with climate change exacerbating the number of extinctions. However, in certain regions of the world — mainly in Asia — they found patterns which patterns were broadly unaccounted for by either of these two drivers, and called for renewed focus on these neglected areas for further study.
In short, their theory only works some of the time, despite supposed being the nail in the coffin of a 50year-old debate.
Lewis Bartlett, a researcher from the University of Exeter’s Centre for Ecology and Conservation, said: “As far as we are concerned, this research is the nail in the coffin of this 50-year debate — humans were the dominant cause of the extinction of megafauna. What we don’t know is what it was about these early settlers that caused this demise. Were they killing them for food, was it early use of fire or were they driven out of their habitats? Our analysis doesn’t differentiate, but we can say that it was caused by human activity more than by climate change. It debunks the myth of early humans living in harmony with nature.” More.
Straw man alert: No serious analyst sponsors a “myth of early humans living in harmony with nature.”
The obvious problem is that correlation is not causation. The same forces that caused early humans to migrate may have doomed the mammoth as well, without direct cause and effect. Without being there, it is difficult to know.
Here’s the abstract:
Debate over the late Quaternary megafaunal extinctions has focussed on whether human colonisation or climatic changes were more important drivers of extinction, with few extinctions being unambiguously attributable to either. Most analyses have been geographically or taxonomically restricted and the few quantitative global analyses have been limited by coarse temporal resolution or overly simplified climate reconstructions or proxies. We present a global analysis of the causes of these extinctions which uses high-resolution climate reconstructions and explicitly investigates the sensitivity of our results to uncertainty in the palaeological record. Our results show that human colonisation was the dominant driver of megafaunal extinction across the world but that climatic factors were also important. We identify the geographic regions where future research is likely to have the most impact, with our models reliably predicting extinctions across most of the world, with the notable exception of mainland Asia where we fail to explain the apparently low rate of extinction found in in the fossil record. Our results are highly robust to uncertainties in the palaeological record, and our main conclusions are unlikely to change qualitatively following minor improvements or changes in the dates of extinctions and human colonisation (paywall) – Lewis J. Bartlett, David R. Williams, Graham W. Prescott, Andrew Balmford, Rhys E. Green, Anders Eriksson, Paul J. Valdes, Joy S. Singarayer, Andrea Manica. Robustness despite uncertainty: regional climate data reveal the dominant role of humans in explaining global extinctions of Late Quaternary megafauna. Ecography, 2015; DOI: 10.1111/ecog.01566
Follow UD News at Twitter!
In any event: