I like to comment on the original topic:
Climate change could drive a million of the world's species to extinction as soon as 2050, a scientific study says.
The authors say in the journal Nature a study of six world regions suggested a quarter of animals and plants living on the land could be forced into oblivion.
They say cutting greenhouse gases and storing the main one, carbon dioxide, could save many species from vanishing.
The United Nations says the prospect is also a threat to the billions of people who rely on Nature for their survival.
http://news.bbc.co.uk/2/hi/science/nature/3375447.stm
So what did they do?
Exploring three approaches in which the estimated probability of extinction shows a power-law relationship with geographical range size, we predict, on the basis of mid-range climate-warming scenarios for 2050, that 15–37% of species in our sample of regions and taxa will be 'committed to extinction'. When the average of the three methods and two dispersal scenarios is taken, minimal climate-warming scenarios produce lower projections of species committed to extinction (18%) than mid-range (24%) and maximum-change (35%) scenarios. These estimates show the importance of rapid implementation of technologies to decrease greenhouse gas emissions and strategies for carbon sequestration.
Which three methods?
We explore three methods to estimate extinction, based on the species–area relationship, which is a well-established empirical power-law relationship describing how the number of species relates to area ...
In method 1 we use changes in the summed distribution areas of all species...
in method 2 we use the average proportional loss of the distribution area of each species to estimate the fraction of species predicted to become extinct.
Thus, in method 3 we estimate the extinction risk of each species separately by substituting its area loss in the species–area relationship, before averaging across species
Source:
Nature 427, 145 - 148 (08 January 2004); doi:10.1038/nature02121
Extinction risk from climate change, Thomas et al.
That's it. So not why method 4? and test your hypothesis and check how many species became extinct with earlier violent climate changes in the recent past.
The Pleistocene Holocene boundary: bingo: about 10-20 degrees assumed temperature change and we have a massive extinction of megafauna, Mammoths Mastodonts, giant ground sloth, etc. Many google hits on those keywords. Good start.
So Hypothesis proven?
How about the Dansgaard Oeschger events?
http://www.ngdc.noaa.gov/paleo/icecore/greenland/summit/document/gispinfo.htm
The isotopic temperature records show 23 interstadial (or Dansgaard/ Oeschger) events first recognized in the GRIP record (Dansgaard et al., 1993) and verified in the GISP2 record (Grootes et al., 1993) between 110 and 15 kyr B.P. These millennial-scale events represent quite large climate deviations; probably many degrees C in temperature, twofold changes in snow accumulation, order-of-magnitude changes in wind-blown dust and sea-salt loading, roughly 100 ppbv in methane concentration, etc., with cold, dry, dusty, and low-methane conditions correlated (Alley et al, 1993; Taylor et al., 1993b; Mayewski et al, 1993c, 1994; Chappellaz et al, 1993).
These events are regional to global since they are observed in local climatic indicators such as snow accumulation rate and the isotopic composition of snow linked to temperature, in regional climatic indicators such as wind-blown sea salt and continental dust, and in regional-to-global indicators such as atmospheric concentrations of methane, nitrate and ammonium. Reorganizations of atmospheric circulation are indicated clearly (Mayewski et al, 1993c; 1994b; Kapsner et al, 1995).
So we it seems that we had enormous climatal upheaval in the 60ky -25ky BP timeframe. If a few degrees temperature change of Thomas in several decades is good for 25% how about 23 events of more than 10 degrees temperature change within a decade. Wouldn't it be good for 23 x 25% extinctions at least. So, did we have mass extinctions? I couldn't find any other than the previous mentioned P-H event.
So how many species became extinct during the transition to the assumed Eemian interglacial 130-135 Ky ago, that was as fierce as the transition to the Holocene? I couldn't find anything going on.
How about the other some 8 interglacials in the last million years, much upheavel in climates but mass extinctions? Please show them to me.
Another marked climate upheaval was the Paleocene/Eocene boundary (~55 Ma) when it was believed that massive CO2 discharges from oceanic clathrate caused a severe global climate change. So when was the last mass extinction? right the K-T boudary 65 Mya. 55 My ago mammal species were emerging rapidly taking the niches that the dino's left behind. No mass extinction.
It is incredible, nay, infuriating, that this paper past the peer review. But as long as you support the erratic anthropogenic global warming theory, you can just about say anything, but in the mean time science succumbs.
