People know global warming is real and humans are partly to blame, but less than a quarter of them are very or extremely worried about it, according to an Associated Press-NORC Center for Public Affairs Research mid-October poll.
“Usually when we hear about global warming everything seems so distant. The sea levels are going to rise but I find it difficult to find a prediction that tells you how many years exactly,” said Renata Schram, a 43-year-old customer service representative in Sturgis, Michigan in the AP story reporting the poll’s results.
Sea-level rise is, in fact, something we should worry about, says Dr. Jim White, Director of the Institute of Arctic and Alpine Research at the University of Colorado Boulder. White’s specific area of expertise is paleoclimatology, studying past climates to better understand our current and future climates. He thinks sea-level rise is what will finally get people to stop talking about believing in global warming and instead start worrying about it.
Historically, a 1 degree Celsius (1.8 degrees Fahrenheit) change in the planet’s temperature results in a 20 meter (66 feet) change in sea level, according to White. The UK Met Office announced in October that 2015 was the first year to be 1 degree Celsius above pre-industrial levels. We could warm another degree as soon as 2036, well within most of our lifetimes, according to prominent climate scientist Michael Mann.
What does a 20 meter sea-level rise look like?
White has a simpler way for Americans to think of the impact of sea level rise. “Delaware, first state in, first state out.” It will be the first state we lose to the rising seas, White says.
Those farther inland or on higher ground shouldn’t think they will be spared either. If the West Antarctic Ice Sheet collapses, 26 million people in the United States could be displaced, according to a report last year in the Proceedings of the National Academy of Science. Those people will need to move somewhere.
Additionally, the United States will try to prevent or minimize the damage caused by rising seas. The federal government funded a $335 million wall to protect Manhattan. How much more taxpayer money will be needed to protect Houston, New Orleans, Miami, Charleston, Washington, D.C. and other cities?
The Intergovernmental Panel on Climate Change (IPCC) has a much more conservative outlook than White on sea-level rise. The panel projects less than 1 meter rise by 2100. But IPCC models don’t incorporate large glaciers well, so they don’t forecast the sea-level rise associated with temperature increases well, according to White.
Scientists don’t know precisely the rate of sea-level rise because of uncertainty over the melting rate of marine ice sheets, such as the one in West Antarctica.
The point at which an ice sheet starts to float in the ocean is called the grounding line. One hypothesis proposes that movement of this line inland to a certain point on the seabed floor can trigger rapid melting of the ice sheet. If this happened in West Antarctica, White says, the ice sheet could collapse and drive the dramatic sea-level rise.
White’s wife bought him a t-shirt that says, “Science, it doesn’t care what you believe.” Regardless of whether Americans worry or not, the planet will keep warming and ice will keep melting if humans continue emitting carbon at our current pace.
“Sea-level rise, it’s going to get you,” said White.