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The Flooded Earth

John Tarleton Nov 19, 2012

Hurricane Sandy lifted up the ocean and slung it in our face — a salty, stinging lesson in how close we live to the sea. For Peter D. Ward, New York’s inundation came as little surprise.A University of Washington paleontologist and expert on how past episodes of climate changed have dramatically altered life on Earth, Ward authored The Flooded Earth: Our Future in a World Without Ice Caps in 2010. Grounded in science, the book is a creatively envisioned postcard from a future in which humans have failed to halt and reverse global warming. The book bombed commercially — it was the least successful of the more than a dozen books Ward has written. “People don’t like to hear bad news,” he says. Surrounded by bad news, but grateful to have a working phone and internet connection, I called Ward a few days after the storm to learn what else the ocean might have in store
for us.

JOHN TARLETON: What does the future hold for coastal cities like New York?

PETER WARD: If carbon emissions continue to increase, we could be at 600 parts per million of carbon dioxide in the atmosphere by 2100, higher than anytime since a few million years ago when the planet was much warmer. We know from the record that when we reach 1,000 parts per million of carbon dioxide and stay there long enough, ice sheets have completely melted. This means oceans would rise 240 feet higher than they are today which would wipe out all the world’s coastal cities.

JT: Why does a three-foot increase in sea level matter?

PW: If future storms like Sandy start from a tidal height that is three feet higher, that will hugely increase the destructive power of their storm surge. The impact I would be way more concerned with is the salinization of croplands as seawater goes laterally a long distance.

We’ve seen the start of this problem in the San Joaquin Valley in California. River deltas where much of the world’s food is produced, such as rice in Asia, are in great peril from encroaching salt water. If crops fail and there is famine, you could see enormous unrest and gigantic numbers of people moving from one country to the next.

JT: Research into past instances of climate change show it can happen quite rapidly. How close are we to stumbling into runaway global warming?

PW: We’re at 391 parts per million of carbon dioxide in the atmosphere. It’s said if we can keep it below 450 ppm, we can avoid runaway global warming. But no one knows.

JT: How does a warming world affect the physics and chemistry of the oceans?

PW: The Earth warms way more at the poles than it does at the equator. So if you warm the poles and don’t increase the temperature in the equator, the all-important temperature difference between the poles and the equator gets lower and lower.

This matters because the only thing that makes currents on this planet is a cold high-latitude and the warm mid-latitude and warm equator. Once you’ve got pretty much the same temperature from pole to equator, there is no wind. There is no high-pressure and low-pressure cells. Ocean currents stop. When that happens, oceans becomes depleted of oxygen and a new type of bacteria takeover that produces hydrogen sulfide which is poisonous and causes mass extinctions that are quite horrid. It’s like a World War I shelling by gas.

That would take millennia to happen, but new computer models suggests that big ocean current systems in the Pacific Ocean could start noticeably slowing down early in the 22nd-century followed by the Atlantic about a century later.

JT: How has your research into past mass extinction events shaped your understanding of what we’re experiencing now?

PW: Global warming has caused every single mass extinction event except the demise of the dinosaurs. And even in the case of the dinosaurs, there was a precursor extinction just before the asteroid hit.

JT: You’ve spent a lot of time contemplating the catastrophes of the ancient past as well as the present.

PW: I think about it like Dickens’ Christmas Carol. That’s a powerful story because things change. What I try to do is show people the Ghost of Christmas future so they recognize the future does not have to be that way.