Many deniers of human-caused climate change substantiate their denial with the fact that global warming happened before. Long before humans walked the Earth, 56 million years ago. We didn't cause it then, so how could we cause it now?
Lee Kump can answer that. In a world of 7 billion people, he is one of the few of us who really knows and understands.
Dr. Kump is a "Professor in the Department of Geosciences, and an associate of the Earth System Science Center and Astrobiology Research Center at the Pennsylvania State University."
He is also one of the authors of The Earth System, "The first book of its kind to address the issues of global change from a true Earth systems perspective."
And if you pick up a copy of the current Scientific American, you can read Dr. Kump's article, "The Last Great Global Warming."
Surprising new evidence suggests the pace of the earth's most abrupt prehistoric warm-up paled in comparison to what we face today. The episode has lessons for our future."
Visiting "Spitsbergen, the largest island in Norway's Svalbard archipelago," Kump imagines "a time when palm trees, ferns and alligators probably inhabited this area." And it is there Kump looks for and finds clues to Earth's past...and her future.
Research had indicated that in the course of a few thousand years -- a mere instant in geologic time -- global temperatures rose five degrees Celsius, marking a planetary fever known to scientists as the Paleocene-Eocene Thermal Maximum, or PETM. Climate zones shifted toward the poles, on land and at sea, forcing plants and animals to migrate, adapt or die. Some of the deepest realms of the ocean became acidified and oxygen-starved, killing off many of the organisms living there. It took nearly 200,000 years for the earth's natural buffers to bring the fever down."
Like now the cause of this ancient warming was "a massive injection of heat-trapping greenhouse gases into the atmosphere and oceans comparable in volume to what our persistent burning of fossil fuels could deliver in coming centuries."
Back then, the Earth consisted of one immense supercontinent we now call Pangea. As it entered the final stages of its dissolution, it released a cataclysmic explosion of carbon dioxide and methane gases, consisting of hundreds of billions of tons of carbon "enough to raise global temperature a couple of degrees."
But that was just the beginning. "A second, more intense warming phase began when the volcano-induced heat set other types of gas release into motion." As the atmosphere warmed, the oceans heated up as well, thawing out frozen methane hydrate deposits buried deep in the seabed.
"As the hydrates thawed, methane gas bubbled up to the surface, adding more carbon to the atmosphere." Adding approximately 1.7 billion tons of carbon each year over 20,000 years, it caused a warming of 0.025 °C per century, reaching an overall temperature rise of 5 °C.
Now while the rate of warming 56 million years ago was 0.025 °C per century, current trends suggest a minimum rise of 1-4 °C just this century. And while it took 20,000 years for the Earth to heat up by 5 °C back then, current trends will see a rise of 2-10 °C over the next 200-300 years.
Kump tells us that when you compare the present warming with the last one, "the climate shift currently under way is happening at breakneck speed."
In a matter of decades, deforestation and the cars and coal-fired power plants of the industrial revolution have increased CO2 by more than 30%, and we are now pumping nine petagrams (one petagram equals one billion tons) of carbon into the atmosphere each year."
That rate is expected to reach 25 billion tons a year until all fossil-fuel reserves are exhausted.
Current global warming is on a path to vastly exceed the PETM, but it may not be too late to avoid the calamity that awaits us. To do so requires immediate action by all the nations of the world to reduce the buildup of atmospheric carbon dioxide and to ensure that the Paleocene-Eocene Thermal Maximum remains the last great global warming."
Scientists always end with these positive, hopeful messages, telling us it's not too late if only we wake up and alter our course. Why do we have such trouble admitting the truth? Of course I hope we respond in time, but at the moment we should be completely honest that we are doing absolutely nothing about this and we have no plans to do anything. That is our greatest shame. That we know what is coming and we refuse to act and we carry on as if it isn't really happening.
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