Rising Sea Level a Slow Moving Freight Train

By the turn of the century Miami will be underwater. That is the sobering news from James White, director of the Institute of Arctic and Alpine Research.

“The sea level that’s rising now is a slow freight train that’s already moving,” said White, speaking to my science writing class at his laboratory on October 18. “It won’t stop at the year 2100. It will keep rising. This means big trouble for cities like Miami, Norfolk and Philadelphia.”

White’s bleak predictions are based on climate models and data sourced from ice cores drilled deep below the ice sheet in Greenland and the Antarctic. Recently, White has been working alongside scientists from 14 countries at the North Greenland Eemian Ice Drilling project. The team began drilling in June 2009. This August they hit bedrock, some 8,300 feet beneath Greenland’s frigid surface.

The multiple layers of the Greenland ice sheet hold valuable information about atmospheric conditions, including air temperatures, moisture levels, and the concentrations of greenhouse gasses, dating back hundreds of thousands of years. The deepest layers of ice were formed throughout the Eemian period, which occurred during the last ice age. Spanning from 130,000 to 115,000 years ago, the Eemian was what scientists call an interglacial period: a transitory interval of warmer global temperatures between cold periods of rapid glacial production.

The Eemian was the last time the Earth’s average temperature was as warm as it is now. It was six degrees Celsius warmer in the Arctic and sea level was three to five meters higher than we know it, White said.

This makes the Eemian a good gauge for predicting how rapidly sea level will rise in line with present and predicted warming conditions, which are the result of increased greenhouse gas concentrations in the atmosphere due to human activities, White explained.

White and his colleagues use data from the Eemian ice core to analyze how much of the Eemian sea level rise was a result of parts of Greenland melting. Similar research is done in Antarctica to measure how the melting of the Antarctic ice sheet contributed to sea level rise. This information should provide insights into how rapidly these regions will melt under warmer conditions in the coming decades, White said.

White pointed out that sea level rise will severely damage infrastructure at coastal cities. “With a three feet rise Miami’s airport is under water. Imagine sewer systems don’t work anymore. Any buried electrical lines are in trouble; roadways are in trouble,” he said.

White believes that careful and informed decisions regarding city engineering need to be made at the political level. “The question is how far do you go inland before rebuilding again?” he said.

White affirmed that humans will not destroy the planet because Earth has experienced higher concentrations of atmospheric carbon dioxide and extreme temperatures in the past. But we will drive other species to extinction and create challenges for our own survival, he said.

“We’ve predicated modern societies on our climate. There are abundant examples from the past where societies collapsed because of climate change,” he cautioned.

“One generation passes its problems onto another. We had every bit of intelligence to deal with this problem in the 1950s. We ignored it then. What I find astounding is that we ignore it now.”

Image: NEEM ice core drilling project – www.neem.ku.dk


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