News From Antarctica Is Not Good
This week’s Scientific American has a significant article “Antarctica’s Ice Shelves Thin; Threaten Significant Sea Level Rise” by Andrea Thompson and Climate Central. It continues the recent litany of news from the mysterious continent — the one that will determine when all coastal cities will start to experience catastrophic sea level rise. I would like to add a few comments since this very good piece directly supports my area of research and public presentations. Few realize just how ominous the news out of Antarctica is. Month by month the evidence is screaming at us, that we have crossed into the proverbial terra incognita — unknown territory. We have trouble grasping what has started to occur, because sea level has not been higher than present for 120,000 years.
Not only have we broken out of millions of years of natural cycles of “ice ages” roughly every hundred thousand years, but the current levels of elevated ocean heat essentially guarantee that sea level will rise far beyond the last high mark, which was a difficult-to-imagine, twenty five feet above present. While that could not happen this century, it is time to understand the facts and re-engineer our coastal environments for the greatest change imaginable: a gradually shifting shoreline.
The six “Pine Island Glaciers” in West Antarctica plus the Totten Glacier in the east, hold enough ice to raise global sea level more than 30 feet (10 meters). Unlike storm surge, sea level rise is global and will not recede. The fact is we do not know — and can not presently know — exactly what decade the water level will start to rise quickly and visibly. Those glaciers are miles thick, tens of miles wide, and more than a hundred miles long. There is no way to model exactly WHEN they will “disgorge” or slide into the sea. It is rather like being up in snow-covered mountains and being told the conditions are right for an avalanche — that could happen two minutes from now, or two weeks from now. The forces and dynamics for avalanches cannot be precisely predicted any more than we can know when an earthquake will happen. The same for the collapse of Antarctic glaciers.
What we do know is this. Modern technology now shows us detailed images down deep and even under the miles of ice. We can see the topography and contours of those monstrous rivers of ice. The physical dynamics are such that gravity will bring them to the sea as they continue to warm. There is nothing to stop their slide. As they go from land to sea, that is the moment when the ocean rises, like adding an ice cube to a glass of water. The warming and melting is occurring way ahead of the models. The good news is that it appears that the really catastrophic sea level rise will not occur for several decades at least, giving us time to plan on how to adapt.
Our entire human civilization has been built up during a period without substantial sea level change. We came along essentially at the turning point between the long cycles of rise and fall, the 300 – 400 feet (100 meters plus) of sea level change that occurs roughly every hundred thousand years. Because the time perspective of human history is only a few thousand years, sea level appeared not to change — similar to arriving at an ocean inlet during the twenty minutes of ‘slack tide’ when the water level neither rises nor falls. We were fooled into thinking that sea level and the shoreline were quite stable.
Now the ocean is rising as surely as ice melts at 32 degrees F. Rising sea level will move us upward and inland. The Scientific American article helps to put the latest scientific research into plain language that should engage a wider audience than the much more technical scientific journals that publish original research. It is time to start adapting to sea level that will keep getting higher for centuries — much higher. It is now unstoppable.
While it may be tempting to dismiss this as ‘not our problem’, those who are concerned about their legacy to grandchildren and beyond will take this seriously. It will be one of the biggest challenges humankind ever faces. And this future crisis has already begun to have effects. Coastal cities around the world are seeing streets flood every 28 days with the peak tides, often called “king tides.” Miami Beach just installed $15 million dollars of pumps to keep the salt water off the streets on the days of peak monthly high tide. It is the first phase of a $300 M plan. Record high floods occurred again in London this week, surpassing the previous record last month. From Boston to Bangladesh and from Monaco to Manilla, flooding has become routine and can be predicted to the minute by the lunar tide cycle. Salt water intrusion is noticeable in some coastal aquifers. Those manifestations will worsen over the coming decades — the harbinger of the essentially permanent rise of the ocean.
Like most crises, rising sea level will also present opportunities. By mid century rising sea level will destroy more assets globally than any other cause. Coping with the problem will also become a huge business. It may be the ultimate “glass half empty or half full.” That’s the message I share in my presentations to diverse audiences. Metaphorically, the water is already ‘at our ankles.’ Hopefully we will pay attention and adapt before it gets to our chin.
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[NOTE: In my book, “High Tide On Main Street: Rising Sea Level and the Coming Coastal Crisis”, I cited a slightly different calculation for sea level rise when all of Antarctica melts. The Scientific American article referenced, uses ‘more than 200 feet’, whereas I cited 186 feet. I stand by my research, but the difference is a quibble and of course immaterial.]