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Climate change is forcing rising seas and dropping lake levels, according to experts: (L to R) Anthony Oliver-Smith from the University of Florida, Ben Strauss from Climate Central and Phil Willink of the Shedd Aquarium.


Climate change drives rising seas and shrinking Great Lakes

by Kate Van Winkle and Lyndsey Gilpin
Jan 15, 2013


Climate change is driving rising seas and the threat of more East Coast floods while lake levels drop and drought dries out the Corn Belt, according to a panel of researchers who presented at Shedd Aquarium Monday night.

 

“There is one species that has trouble with change, and that would be people,” said Phil Willink, senior research biologist at the Shedd.

Experts on climate change estimate that, at current rates or global warming, sea levels could climb as much as 25 feet within the next 100 years, submerging coastal areas and leading to record flooding.

“We’re looking back a few hundred years and forward a few hundred years, but the question is how will our descendants be looking back on us?” asked Ben Strauss, COO and director of the Program on Sea Level Rise at Climate Central, located in Princeton, N.J. 

Warming trends have also led to a significant glacial retreat, melting that dumps large amounts of fresh water into seas and contributes to rising water levels. In the last decade, ice melted at a rate 10 times faster than in the 1990s, according to Strauss.

Meanwhile, water levels in the Great Lakes continue to fall with drought conditions and leave many concerned about the water supply for communities, crops, ecosystems and shipping industries. The Great Lakes hold 20 percent of the world’s fresh water reserves.

During the Shedd event, experts from Climate Central, the University of Florida and aquarium gathered in a panel to discuss current data and long-term projections regarding changing water levels and the impact on human populations.

According to Willink, water levels in the Great Lakes are constantly fluctuating, with alternating periods of high and low levels recorded throughout history. Lake Michigan also experiences a fluctuation between one and two feet in the course of a year.

Current lake levels, however, have scientists looking for explanations beyond historical trends. While decreases are common, this time lake levels are at near-record lows and don’t seem to be bouncing back.

“There are still fluctuations,” Willink said, “but something else seems to be going on here.”

Willink said a number of factors contribute to falling lake levels, including precipitation and evaporation rates, waterway construction projects and general warming trends.

According to Willink, most models predict a long-term average of one to two feet decrease in water levels in the next 100 years.

This drop could have a significant impact on near shore wetland environments, which typically only have a few feet of water. However, these environments can shift with the water level if conditions are right and the drop is gradual.

“The trick is, it really depends on the rate of change,” Willink said. “If it drops quickly, wetlands may not have time to change.”

Sea levels, however, are a different story. Strauss presented about rising sea levels and the impact on coastal areas.

Sea levels have risen an estimated 15 inches since the 1880s. Sinking land accounts for seven inches of this increase, Strauss said. The remaining eight inches, Strauss said, can be attributed to global warming trends including overall water temperature increases and the retreat of glaciers.

“Whether it’s a long term trend or fluctuation, we can’t tell,” Strauss said of glacial retreating.

Strauss estimates that because of the effects of warming trends, every coastal flood is about eight inches higher than in the past. This means flooding effects entirely new populations. For example, with an average of 6,000 people per vertical inch, New York City has an estimated 50,000 additional people at risk for flooding. According to Strauss, sea level rise was a certain contributor to hurricane Sandy, which created a storm surge of almost 14 feet in New York.

The issue of displacement and resettlement due to rising sea levels was the topic of a presentation by Anthony Oliver-Smith, a professor of anthropology at the University of Florida.

“When we see the outcome of a disaster, we’re seeing the people who are exposed and vulnerable,” Oliver-Smith said.

According to Oliver-Smith, exposure refers to geographically at-risk areas like coasts and lowlands. On the other hand, Oliver-Smith classifies vulnerability as a “socially constructed position” encompassing social, political, cultural and economic factors.

He estimates that nearly 15 million people in Bangladesh and Vietnam are at risk of flooding from just one meter of sea level increase.

“What we’re going to see is the inland reach of storm surge,” Oliver-Smith said.

Oliver-Smith cautions that issues of displacement and resettlement will continue to be an issue as sea levels push more and more people from their homes.

“People grieve for a lost home the same way they grieve for a lost person,” Oliver-Smith said. “We need to see resettlement as an investment and include the people in that investment.”

The “Social and Biological Impacts of Rising Seas and Reduced Lake Levels” was cosponsored by the University of Chicago Center for International Studies and Program on the Global Environment, and the Shedd Aquarium.