August 24th, 2010 by Zachary Shahan
12% of Mexican lizards have gone extinct from global warming in the past 25 years, 4% have gone extinct worldwide, and 39% are expected to go extinct worldwide from global warming by 2080.
I’ve written on lizards going extinct from climate change in the past, and I’m sure others have as well since theoretical models predict that 20% of lizard species will go extinct from climate change. A scientific paper out this year not only confirms that they will go extinct, but shows that they already are, and that only 20% going extinct would be a good thing.
The paper, Erosion of Lizard Diversity by Climate Change and Altered Thermal Niches (Sinervo 2010), compares global observations of 48 Mexican lizard species from 1975 to 2009. The evidence is clear — lizard species are already rapidly going extinct.
Since 1975, 12% of lizard species in the 200 Mexican sites studied have gone extinct. Local extinctions correlated with weather station data, as would have been expected.
You would think that lizards and other animals could survive by either adapting to a hotter climate or migrating. The first is too hard to do for most species, because the world is warming too fast. The latter, when possible, amplifies extinction of other species as unfamiliar, invasive move in.
This all leaves a pretty bleak future for many species. Lizards have already crossed a key threshold, it seems, and who knows how many more years of extreme CO2 emissions and rapid warming we will see before things turn around.
As John Cook of Skeptical Science points out, the fact that temperature lags CO2 emissions means temperatures will rise even long after we cut emissions — “if we manage to reduce CO2 emissions over the next few decades, this will reduce the number of species extinctions in 2080 but have little effect on the extinctions by 2050. A slow down in global warming will lag atmospheric CO2 levels by decades.” Additionally, as I discussed this last weekend, there are feedback loops that make warming cause CO2 emissions and then CO2 emissions again cause warming. Not a bright future.
In the case of lizards, the scientists of the study above estimate that 4% of lizard species worldwide went extinct from 1975 to today and they predict that 39% will go extinct by 2080.
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