As Greenland and Antarctica melt the Gulf rises near New Orleans

 Greenland and Antarctica are strong contributors to sea-level rise around New Orleans.

Climate change is melting giant ice sheets covering Greenland and Antartica faster than previously expected, scientist have uncovered. As the ice melts, the rate of sea level rise will increase in South Louisiana, according to a new NASA tool that links melting of specific ice sheets to 293 affected coastal cities.
Though Greenland and Antartica may seem too far away to have such a direct impact on the Big Easy, the distance between the locations actually increases the impact, said Eric Larour, the project lead and co-developer of the Ice Sheet System Model.
Ice sheets have enough mass that they exert their own gravitational force, attracting nearby waters. As the ice sheets melt, water nearby recedes. "This means, that close to the ice melting, sea level decreases, but far from it, it increases," Larour wrote in an email.
Furthering this effect is bedrock rebound below ice sheet melting. Bedrock rebound works like a foam mattress that expands back up when you wake up and get out of bed in the morning, Larour said. As ice melts, reducing its weight, the bedrock below rebounds pushing away nearby waters and dropping the sea level near the source of the melting.
Combined, these factors are why the melting of Greenland and Antartica will have a greater impact on sea level rise around New Orleans than melting in Alaska. While the melting of northwestern glaciers in Alaska will contribute to sea level rise in New Orleans, melting of glaciers in southeastern Alaska will actually decrease sea level near New Orleans because of the gravity effect.
In addition to these factors, as climate change warms the oceans it causes water to expand. This accounts for about 50 percent of sea level rise in coastal cities around the globe while melting of all the ice in the world contributes to about 46 percent of sea level rise in New Orleans.
Sea level rise in South Louisiana is compounded by sinking land, also known as subsidence. The highest sea level rise estimate in the state's 2017 coastal master plan predicts sea levels will increase by 2.72 feet over a 50-year period.
Partial melting of the Greenland ice sheet would cause a 3-foot rise in sea level, according to the NASA website. But determining the probability and time frame of the melt has proven difficult, Larour said. That's because the models cannot keep up with the observed melting. Previous models have proven overly conservative. "And, that's not a good thing," he said.

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