Earth Day good time to ponder impact of mankind on planet

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By For The Columbus Dispatch  • 

Those earnest about Earth Day, which began in 1970 as a way to raise awareness about the trashing of nature, must count small victories because evidence in the oceans and the atmosphere suggests a planet could still be lost.

That there have been conservation and environmental successes since 1970 is indisputable.

In Ohio, for example, hunters can hunt whitetail deer where no deer dwelled 44 years ago and wild turkeys where no turkeys roamed for decades. Trappers can snare once-missing beavers and river otters. Fishermen of a certain age have seen Lake Erie, declared dead during the 1960s, rise in repute as the “walleye capital of the world” during the 1980s.

Wildlife watchers in Ohio are able to witness the irregular though increasingly frequent apparitions of bobcats and bears, as well as get regular views of cormorants, bald eagles, ospreys and peregrine falcons where none used to live. Downtown Columbus is home to peregrines; Hoover Reservoir holds both eagles and ospreys.

The birds of prey — and probably many preyed-upon birds — have found their way back after the pesticide DDT was eliminated for most uses in the U.S. Their return was aided by habitat restoration and human intervention of the positive kind, much of it paid for by hunters and fishermen.

Migrating birds, though, perish by the millions annually as they fly into tall buildings across North America. House cats kill millions more birds. West Nile virus, an imported contagion, has provided birds with yet another way to die.

Hurt in numbers by the transformation of farm practices are hunted-in-Ohio species that include ruffed grouse, bobwhite quail and ring-necked pheasants. Agriculture, too, gets most of the blame for nutrient-laden runoff that has created harmful algae blooms devastating to Grand Lake St. Marys and threatening to Lake Erie’s fish, fowl and human residents.

Having weathered — more or less — invasions by sea lampreys, spiny water fleas, zebra mussels, quagga mussels, round gobies and white perch, Lake Erie and its tributaries are likely to find out sooner than later what happens when one of several varieties of Asian carp take up residence. The invasive silver and bighead carps unleashed by humans already are wending their way up the Ohio River into the state’s tributary streams.

The Cuyahoga River hasn’t caught fire for decades.

Yet pharmaceuticals are concentrated enough in Lake Erie to kill microorganisms at the base of the food web. The lake is rife with microscopic bits of plastic. Blue-green algae create toxins while alive and create low-oxygen “dead zones” when they die and decompose.

The wiping out of Ohio’s ash trees is continuing apace after the emerald ash borer, an invasive insect from Asia emerged from some packaging wood near Detroit a few years ago. That follows the wipeout during the last century of the American chestnut and the devastation of the American elm caused by invasive insects traced to imported wood.

Hemlocks, remnants in Ohio of the last glacial retreat, are threatened to death by hemlock woolly adelgid, yet another invader from east Asia. Additionally, thousand cankers disease, a destroyer of black walnut trees that hadn’t shown up anywhere in North America until 2003, has been found in southwest Ohio. The carrier is the walnut twig beetle, identified in Arizona as far back as 1929 and which mysteriously began expanding its range only in the last decade.

Bats, victims of a fungus that manifests itself as white-nose syndrome, are dying by the millions during the winter hibernation period. The fungus, which has taken a toll on Ohio bats, is believed to have been carried on the shoes of cave explorers to North America from Europe, where bats show more resistance.

A fungus spread by humans has been identified as the killer of frogs and other amphibians worldwide. The disease has been spread by the apparently immune African clawed frog, a species widely used in research and often sold in the pet trade. The North American bullfrog is thought to be one other amphibian with a built-in immunity to the lethal fungus, though that leaves a lot of native frogs vulnerable.

Globally, March came in as the fourth-warmest on record, marking the 349th straight month during which average temperatures exceeded the 20th century average. The average global temperature in 2013 was the fourth- or seventh-highest on record, depending on which data set was used to measure. Nine of the 10 highest annual average world temperatures have been recorded in the 21st century. For each of the past 39 years, average annual world temperatures have surpassed the 20th century average.

The oceans, meanwhile, are becoming more acidic, a direct threat to shell-making animals and to corals that already is having devastating effects. The oceanic transformation, scientists say, is fallout from carbon in the atmosphere.

On the whole, even an abbreviated biological reckoning suggests Earth Day 2014 has to be different from Earth Day 1970 if for no other reason than humans during the past 44 years, though but a blink in geological time, have made a different Earth.