Migrations and Climate Change

As our climate changes at an ever-increasing rate, everything from bacteria to blue whales are on the move. Climate changes have come and gone over the ages but rarely at the rate we are inducing by our profligate production of Carbon Dioxide from the burning of fossil fuels. Both plants and animals alike have only two choices – migrate or die.

Species migrations are generally are to the north or upslope, in either case to cooler climes that existed before global warming. Some migrations have little impact on humans. The Arctic is a bellwether for climate change as it is occurring there more rapidly than elsewhere. Moose are moving north, for the mosses and larch which now have moved northward. Ironically polar bears are moving south. As the ice floes where they hunted seals diminish, they are forced on to land, moving south where they are now competing with grizzly bears.

The now extinct Golden Toad lived in the Monteverde Cloud Forest in Costa Rica. As the climate warmed, it went upslope until it had no higher to go. A smallish mammal, the Bramble Cay Melomys is now extinct. It formerly inhabited an atoll near Papua New Guinea, but sea level rise has inundated the atoll and it had nowhere to go.

Of greater concern to humans are shifting populations of pests. Leishmaniasis is a deadly disease caused by a protozoan parasite. Infection occurs from the bite of an infected sand fly. The sand fly and hence the disease has previously only been seen in the tropics, but the sand fly is now seen in North Texas.

Plant pests that affect food crops are on the move. A moth is moving south(southern hemisphere) ravaging cruciferous crops in South Africa. Coffee plants in Central America are threatened by a fungus due to wetter weather. Wine grapes and olives are threatened in Europe.

Rapid climate change invariably means large scale species extinctions. The greatest rapid climate change is called the Permian Extinction. Around a quarter of a billion years ago, not all that long ago considering the nearly 5 billion year age of the planet, something happened that wiped out about 90 percent of life’s species. It has been suggested that an asteroid a couple of miles across stuck earth.

The debris from the impact, plus induced volcanism from the shock to the mantle would have flooded the skies with ash and poisoned the oceans with sulfuric and other acids. The skies would have drastically darkened and cooled the earth, killing most plant life. The subsequent release of Carbon Dioxide upon their decay would have then drastically warmed the planet. The climatic whipsaws resulted in the extinction of 96 percent of ocean life and over two-thirds of terrestrial life. Rapid climate change is a bad thing for biodiversity and biodiversity is the best measure of a healthy environment.

A physical catastrophe such as an asteroidal impact is out of our control, but we can and must get our impact on the climate under control. No amount of walls and fences will stop starving migrants suffering from climatic change.

Dr. Bob Allen, Ph.D., is Emeritus Professor of Chemistry at Arkansas Tech University.

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