Blog › When climate change is natural and when it very clearly is not


When climate change is natural and when it very clearly is not

Marc Lefkowitz  |  12/06/17 @ 12:00pm  |  Posted in Climate

Timing is everything, and that includes climate change. For 65 million years, the climate has experienced natural changes—as the earth tilted a little on its axis and its orbit stretched, the sun’s energy reaching earth was diminished to the extent that it triggered an Ice Age. A mile-high glacier covered where Cleveland is. Florida’s coast line grew to double its current size.

<br />Dr. Darin Croft presents on Climate Change Past Present and Future. The image is of the tight connection between carbon emissions and planetary rise in temperature between 1880 and Present.<br />A mile high glacier covered Cleveland for 11,000 years. Current climate change is beyond the normal range, scientist who look at millions of years of evidence discovered.

When the natural cycle of the earth's axis tilts and its orbit returns to its normal state, the sun’s energy is restored. In the course of 10,000 years, Cleveland's rolling hills and Great Lake was formed as the glaciers scoured the land and melted into pools. Florida would have been submerged to half its current size due to seas rising as polar ice melted.

This is a normal swing in climate, Dr. Darin Croft, a paleontologist and professor of anatomy at Case Western Reserve University told a crowd at last night’s Institute for Science Origins lecture at the Cleveland Museum of Natural History.

“The swings between glacials and inter glacial periods takes a long time,” Croft explains. “Change is normal. But, if we’re jumping off the swing, we’re really in uncharted territories.”

What isn’t natural is the effect on the climate from burning fossil fuels and releasing heat trapping gas into the atmosphere, Croft said. As carbon dioxide levels rose in the atmosphere in the past 30 years, it has produced the warmest interval in the last 800 years.

Climate scientists discovered this by drilling deep into the polar ice caps and the ocean floor to look for clues about how much carbon is stored inside the layers of geologic (millions of years) time. In the ocean floor cores, one centimeter of soil equals 1,000 years of history. The soil samples reveal that 1,000 years is the time it takes for levels of carbon in the ocean to find a balance after a spike.

The ice cores are a “proxy for thermometers,” he said. “We know there is not a sharp change in carbon dioxide without a big change in temperature. ”

Current climate change has been forced by burning fossil fuels—the spike in heat trapping gas—with the effect being an almost certain rise in global temperatures past 2 degrees Celsius and predicted rise of oceans.

“Sea levels have risen about a foot, ”Croft states. “If we stop (burning fossil fuels), the earth works very slowly. The latest data presents changes that are largely irreversible for 1,000 years. We might be able to restore atmospheric carbon if we had that much time.”

Croft studies the affects of climate change on mammals. As temperature rise, mammals could relocate, he said. Like moose who are migrating northwards, looking for new, undeveloped territory. They could adapt—like coyotes who are able to forage and live in cities. Or, they will go extinct—Croft pointed to the boom in ticks who are not being killed off by freezes and are killing moose calves in the Northeastern U.S.

“Extreme weather is what climate change will mean for us,” he said. “In our neck of the woods, floods will become normal.”

Estimates from the 2017 UN Climate Impact Assessment shows regional impacts: Northeast Ohio could expect 37% more precipitation, which translates to more floods, more bacteria and oil washing into rivers, streams and Lake Erie.

Croft recommends Northeast Ohio start mitigating against the effects of climate change.

“We could cut down on our fossil fuel reliance,” he said. “We could build wind mills and solar farms. For gardeners like me, it may mean I can grow a lot more things that couldn’t before. We have to start getting used to change.”

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