For the first time in 6,000 years sea level is rising, causing the shoreline to move inland. The move will continue for at least 1,000 years. Unless we change the trend of the planet’s heat balance the pace of this movement will accelerate, with disastrous results. We are totally unprepared for this situation.
A week before superstorm Sandy hit New York City my new book High Tide On Main Street: Rising Sea Level and the Coming Coastal Crisis was released. In the book, I describe exactly such a storm hitting that location. The point of my description was to examine the factors that made New York City and the surrounding area particularly vulnerable.
With Sandy there were four things that combined to increase the impact. First there was incredible size of the storm with the unusual track of southeast to northwest. Second, it came at lunar high tide, which is about a foot higher than average; third, sea level has risen about a foot in height over the last century; fourth, the underwater topography off New York harbor amplified the storm surge.
The fact that the scenario portrayed in my book happened exactly a week after it was published is pure coincidence. I did not “predict” Sandy, as was reported on British television and elsewhere.
Here are a few of the facts that I do explain in the book:
The disappearing polar ice cap around the North Pole proves the planet is warming, but has no direct effect on sea level. Contrary to popular perception the ice around the North Pole is floating sea ice. Like an ice cube in a glass of water, when it melts it does not change the level of its surrounding water.
In fact, melting of glaciers is a rather small contributor to sea level rise, and ultimately will only raise sea level by about a foot or two. What will really add to sea level height is the melting of the great ice sheets on Greenland and Antarctica, which sit on top of land. When the Greenland ice sheet melts entirely, sea level will rise about 24 feet. Melting of the Antarctic ice sheets will raise sea level about 185 feet.
Enormous changes in sea level– between 300-400 feet– occur with each ice age. But never in recorded human history has there been a shift like we are seeing now. A brief explanation of the history of sea level rise will help make this clear.
For the last few million years ice ages have occurred as part of natural cycles. Every 100,000 years or so, small variations in the amount of solar energy Earth gets each year, known as the Milankovitch Cycle, change the Earth’s temperature enough to create and then melt ice sheets a couple of miles thick. The last ice age peaked 20,000 years ago followed by thousands of years of warming.
If we were still in the natural cycle of warming and cooling, we would now be heading into another cooling phase about now. The turn would be slow and imprecise, like a “slack tide” as an ocean tide shifts from high to low or vice versa. If you have never seen this, it is the time when the sea shifts directions and appears static or still. The last six thousand years were like slack tide, a turning point.
During that 6,000 years, sea level has not changed much. This happened to coincide with the rise of our civilization and recorded human history. Scientists only came to understand geologic (very long-term) history about a century ago, but most of us are still fooled by the fact that our coastlines have been fixed in place as long as people can remember.
The following chart shows 400,000 years of sea level, global average temperature, and CO2 levels. Note the general synchronized pattern of the three. Also note how the CO2 levels have rocketed off the chart in recent years.
The natural cycle that would otherwise have led us into a cooling phase has been overcome by the warming force that mankind created by burning fossil fuels, which creates what are known as greenhouse gases, trapping heat in the atmosphere. A major contributor to this effect is carbon dioxide.
We emit absolutely massive amounts of carbon dioxide in the atmosphere each year, and so have dramatically altered the natural cycle of cooling and warming of the planet. Again, whereas we would have been entering a cooling phase, we are now heading into an ever-accelerating warming trend that could melt the rest of the ice.
In the last century, sea level rose seven or eight inches. But in the last 30 years the rate of rise has doubled. On the current path, sea level is projected to rise at least three feet, and possibly seven feet by the end of the century. But those projections are actually conservative. They do not allow for two factors that could greatly exacerbate the rate of rise.
Of significant concern is methane. Methane is over 100 times more effective as a greenhouse gas than CO2. As the permafrost, peat bogs, and deep-sea bottom melt, they release huge amounts of methane. Cows also “release” methane but not on the same scale.
Scientists cannot accurately predict when the rest of the trapped methane will be released into the atmosphere. It will happen, though they can’t say whether it will happen tomorrow or 200 years from now. Therefore, they simply leave it out of their calculations.
The melting of certain glaciers within Antarctica will also significantly effect the pace of sea level rise. It is too early to know when they will break up, but some are already loosening and moving more quickly than they have in thousands of years. Melting just a couple of them could raise sea level ten feet this century. Because their melt rates are not predictable, they too are not included in any forecasts and never discussed in most media outlets.
This is all hard to believe. We have grown up understanding that the past will tell us the future. Things follow a pattern. While that is true, our scale of history has simply been too narrow. The time of recorded human history- 6,000-8,000 years is simply not long enough to understand the patterns that influence sea level rise and will influence our lives for the foreseeable future. It’s time for understandings about longer-term, geologic history to become background knowledge for all of us.
When the two great ice sheets — on Greenland and Antarctica — melt again, sea level will be 212-feet higher than it is today. It has happened before and will happen again. It will not happen in our lifetimes, but will happen much more quickly than it has in the geologic past.
Statistical analysis suggests another Sandy-like storm could happen in 15 years. I am not sure we can predict that accurately. Regardless of how soon another storm will hit that location, we have to realize that the long-term rise of sea level demands that we look at the coast differently.
We are in a new era of long-term sea level rise, more storms and erosion, all of which will affect individuals, businesses, communities, and countries.
We need to embrace a realistic program of adaptation. If the ocean is going to be ten feet higher — or more — over the next century or two, we need to start thinking about how we can adapt.
I suggest a five-point roadmap to the future, which I call “Intelligent Adaptation”.
This approach is based on the fact that the more we know about the scale of sea level rise in the decades ahead, the better we can plan for it. The change has started and will be much more obvious by mid-century. It demands honest discussion and practical long-term community planning.
1. Act with a long term perspective, to get the best return on investment (ROI). If you just anticipate a foot of SLR, you will build a certain kind of defense. But once it becomes clear that the rise will eventually get to five feet and higher, that initial defense may be worthless. The efforts of beach restoration, sea walls, and sandbags for storms may work in some places for the short term. But once we confront and accept the longer-term view, we need to think appropriately about actions like elevating buildings, creating serious setbacks for oceanfront property, and bold engineering, like sea walls and major levee control systems, for Chesapeake Bay or San Francisco Bay in the US, or at the Straits of Gibraltar for the Mediterranean.
2. Study the range of projections this century for SLR — just like economic or crop projections. Don’t wait for an exact number to begin to plan and act.
3. Consider the geology and topography at each location. Geologically New York City or at least Manhattan has a plus in that the rock is granite and gneiss, impermeable rocks that can be protected with seawalls up to a considerable height. Miami cannot be saved for centuries due to the Achilles Heel of porous limestone. Sandy demonstrated that the challenge for NYC is that the topography topside and underwater funnels storm surge, raising its level substantially.
4. Recognize the finite future of government bailouts for coastal real estate. We can spend a few hundred billion rebuilding New Orleans; Venice can spend six billion dollars on their protective gates, but these are myopic solutions. When it becomes clear that sea level rise is not a random location event, and will eventually destroy all coastal property, governments will stop compensating people, since no government has enough money to cover all coastal developments and impacts.
5. Anticipate property devaluation. As coastal vulnerability becomes more obvious, the premium prices of waterfront will start to be discounted, and instead be treated more like leasehold land than something you leave in your estate. That change could start this decade. In fact, the devastation of Sandy may have already started to reduce property values of low-lying coastal land. This will have a huge financial impact, affecting companies, communities, and governments (tax bases.) Once the awareness becomes clear, values will start to decrease.
In addition to the five points of intelligent adaptation, there are several actions we should consider at the personal planning level:
1. Look at your investments, particularly real estate. Make adjustments while there is time.
2. Look at your community, with a broader view to impacts. Identify not only which land and property might be flooded, but consider the infrastructure and the effects from surrounding communities being devastated or eliminated. Support adaptation to the reality of rising sea level.
3. Talk to your representatives. Demand that they take this seriously. This is the ultimate issue of ethics, morality, and responsibility for future generations.
We all need to understand the truth about this issue that will change the face of the planet.
My book explains the causes and effects in greater detail. Perhaps more important is that it provides guidance for what this means for you, your family, and your community. We must understand, discuss and ultimately accept a radically different view of our planet.
While sea level rise will produce catastrophes, the good news is that we have decades to plan and adapt. The time to start is now. Future generations will suffer from our inaction. It is a moral issue. It is our legacy.
[disinfo ed.'s note: the article above is based on the book High Tide On Main Street: Rising Sea Level and the Coming Coastal Crisis by John Englander (published by The Science Bookshelf, ISBN: 978-0615637952). This article is published by The Disinformation Company with the kind permission of the book's author and publisher.]
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