Tuesday, April 5, 2011

Extinction is forever

Mass extinctions are nothing new in the history of this planet. Scientists have identified at least five events in the history of Earth in which an estimated 75 percent of all species then on the planet disappeared in a few million years or less. Many scientists believe that we are now in the midst of a sixth such event and that this one is largely being caused by human beings.

The impetus for this suspected mass extinction is human-caused climate change. Scientists suspect that their study which identified this phenomenon may actually be underestimating the impact and just how many species might disappear.

Although it is virtually impossible to link any one species' fate to global warming, there is no doubt that animals' ranges are changing in response to the changing climate. I saw an example of that just today on a road trip here in Southeast Texas. I saw a bunch of Black and Turkey Vultures at a carcass next to the road and when the birds flew up, I noticed that one of them was not a vulture but a Crested Caracara. At one time, this was a Mexican bird, but in recent years they have colonized South Texas and every year they push farther and farther north.

The same thing has happened within the last ten years with White-winged Doves. At one time, they were never seen in this area. Now they are all over the place, especially at my bird feeders.

Birds are very adaptable creatures and they will readily explore new territories if the climate suits them and if they can find the food they need. Other less mobile creatures have more of a disadvantage in adapting to these changing conditions. Moreover, humans place barriers, things like cities and farms and highways, in their way that may make it impossible for them to move to new territories. And in some instances, being unable to move may mean that they are unable to survive.

The thing is, animals - and plants - are already stressed today. A changing climate may just be one stressor too many.

We could, of course, take steps to ameliorate or reverse the situation, but that would mean having to change some of our habits. No need for that because, as Republicans constantly assure us, global climate change is all a hoax anyway. Nothing to see here. Move along. Never mind that mass extinction thing - not your fault.

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