Sunday, December 13, 2009
Do Armadillos show that the world is warming?
picture from here
Often one gets hit with anecdotal stories of animals moving north as evidence of the world's warming. One such animal is the armadillo. I grew up in northern Oklahoma. I didn't know what an armadillo was until my family moved to southern Oklahoma in the early 1960s. They used to scratch for insects outside my bedroom window at night.
A look at the above map will show that Armadillos have been moving north for over a century and that they were just crossing the Red River between Oklahoma and Texas in the early 1960s.
Is this evidence of global warming? I think not. Look at the levels of CO2 in 1880. It was about 290 ppm. When Keeling started in the late 1950s the CO2 was only 315 ppm. One should not have expected a lot of warming during that time. Nor should one expect lots of warming between 1850 and 1900 (and indeed there wasn't.)
But the armadillo started moving in 1850, long before the warming that is ascribed to its migration.
"Prior to about 1850, the nine-banded armadillo was not found north of the Rio Grande river. The sudden and extremely rapid armadillo colonization of the southern United States has puzzled quite a few biologists. The degree of range expansion per year is nearly ten times faster than the average rate expected for a mammal. Sightings of the animals farther north are reported every year, prompting many people to wonder just how far north the armadillo will go." source
Maybe there was a mutation. No one knows why he started moving north. Butone thing is sure. Since there was cooling of the world from 1940 to 1970, one can't say that the continued northward march of the armadillo was due to global warming, when the globe was cooling during that period. Yet during this cooling, he continued his northward trek. But, of course, when it is expedient to grab a fact and make it fit some preconceived viewpoint (that the world is warming and tropical animals will be in Duluth soon), then the armadillo becomes an easy target.
The picture above is the history of the armadillo migration. He started moving north before the warming started. The armadillo didn't care about the cooling or warming, he simply moved north.