New Study Shows Sea Levels Rising Faster, Higher Than Previously Thought (INTERACTIVE MAP)

If you are planning on moving to the shore anytime soon, you’d better think again. According to a new study from Proceedings of the National Academy of Sciences (PNAS), the sea level is rising much faster than previously thought and will be much higher, as well. The conclusion from PNAS is pretty dire:

Global mean sea level has been steadily rising over the last century, is projected to increase by the end of this century, and will continue to rise beyond the year 2100 unless the current global mean temperature trend is reversed. Inertia in the climate and global carbon system, however, causes the global mean temperature to decline slowly even after greenhouse gas emissions have ceased…

That’s a bit couched in science talk but, basically, atmospheric carbon levels are like a very heavy, very fast train. Even if we can put the brakes on it, the mass and inertia involved means it will take a while for the train to stop completely. We have ignored the problem for so long — thank you, climate change deniers and greedy oil & gas companies — that it’s nearly impossible, at this point, to even slow it down.

Previous measurements have indicated that the sea level would rise one inch per decade. But this inertia — known as “lock-in” — shows that rate growing 10 times faster than we thought. This new study by PNAS found that for every degree (Farenheit) of global warming, the global sea level will rise 4.2 feet. When this is multiplied by the current rate of carbon emissions and a best-guess at the global temperature sensitivity to other pollution, it indicates a long-term rise of one foot per decade. This means that a sea level about four feet higher than today is already a foregone conclusion. You can see the charts and read the scientific paper (PDF) if you aren’t easily convinced, and can understand the scientific jargon.

This locked in sea level  — the one we can’t do anything about now — of four feet will submerge over half the population of 316 cities and towns on current coastlines. That’s around 3.6 million people in the lower 48 states. If we don’t act, by the end of this century we will see a rise of 23 feet, jeopardizing over 1,400 towns and cities and an additional 18 million people will be affected. If we do act now, we can keep that down to about 7.5 feet, saving 900 of those places. These numbers were developed by Ben Strauss of, based on the study and on the Surging Seas project, an assessment and map of coastal vulnerability. A visit to this page and a perusal of the interactive map (above) is an eye-opening experience. South Florida will need to severely rethink their idea of “beachfront” property.

Though we can’t be sure of how quickly this will happen, Strauss draws the following analogy:

… it is much easier to know that a pile of ice in a warm room will melt, than to know exactly how fast it will melt.

The study says it may take 2,000 years for the sea level commitments in it to play out. But that estimate is just a guess based on current data. Right now, sea level is rising at a rate of about one foot per century. Average projections indicate that will grow to five feet per century by 2100. Unless we can figure out a way to scrub carbon from our atmosphere, this is a given. It will happen. The carbon we emit today is pretty much irreversible and will last for hundreds, maybe thousands, of years. So, essentially, we don’t know for sure if we’re looking at millenia or merely centuries before the majority of the earth’s coastlines are under water. Just think of that. The people can be moved but, with few exceptions, the buildings cannot. Imagine the historic and beautiful architecture we will lose. It’s heartbreaking.

My husband and I are looking to retire to the Big Island of Hawai’i one day. We look at properties when we visit, searching for that perfect piece of paradise. Talk to the real estate agents and they try to sell you on beachfront — which, with my love of snorkeling, is a lovely thought. But talk to the native Hawaiians, and they will tell you to live mauka, or towards the mountains. They know how dangerous the sea can be.