John’s Blog/Newsletter: SEA LEVEL RISE NOW

One of the challenges raised about transitioning off of fossil fuels is the cost of giving up the relatively cheap energy of coal and similar sources. Of all the fossil fuels, coal is arguably the least expensive, most plentiful, and highest in the amount of carbon dioxide (CO₂) produced with its dominant use in power plants.

It is a fair point to ask about the effect on our economy if we give up, or even diminish, the use of coal. But here is what the “skeptics” and business-as-usual crowd are missing:

What is it going to cost to move every coastal community and infrastructure in the world inland or to higher elevation as sea level rises? If we are going to raise one question about the impact on our economy, we need to ask the other. Both are what economists term “external costs”, those not considered in our usual calculations of benefit and expense.

Rising sea level is now inevitable due to the excess heat already stored in the oceans. The average ocean temperature reading is about 1.5 degrees F (0.85 C) warmer than a century ago. That elevated heat causes direct higher sea level due to a phenomenon called thermal expansion of seawater. The more powerful factor of the glaciers and two great ice sheets in Greenland and Antarctica getting smaller, raising sea level is also assured for centuries due to the warmer ocean. The amount of ice on the planet over the course of centuries is directly related to average global temperature. (See a clear compelling graphic of the relation between temperature, sea level, and CO₂ spanning four ice ages.)

There is a “lag time” of centuries for elevated levels of CO₂ and other greenhouse gases to melt the ice. Even if we halt the rise of heat trapping greenhouse gases, it will take centuries for that to translate into cooling the oceans. In the meantime, we need to begin planning for the effects of the sea moving upward and far inland from the shoreline that has existed for thousands of years. And the damage is not just on the coasts. Rising sea level has effects far inland, on the low land often behind the apparent high beach dunes, and up tidal rivers to inland cities like Washington DC, Hartford, Sacramento, and London, just to name a few.

Though we have had little change in global sea level during the roughly six thousand years of human civilization, geologists have known that the cycles of the ice ages raises and lowers sea level by roughly 350 feet, about every hundred thousand years. (For a complete explanation see my book, “High Tide On Main Street: Rising Sea Level and the Coming Coastal Crisis“)

For the last few thousand years, we were at the turning point, when the natural upward part of cycle, was going to turn into the downward phase for sea level, that would typically last 80,000 years. That phase has been negated — by us. Sea level must rise for centuries, due to the elevated ocean heat that will melt the ice, raising sea level, and slowly shift the shoreline inland. (See my post about Sea Level Rise in Just 4 Key Points.)

Moving to higher ground  is something we are quite unprepared for. It will be a very expensive adaptation. The sooner we start the better. In fact those who see this new reality sooner will be able to reduce their “cost” by designing and investing in assets that can better deal with ever rising sea level. If we are going to build buildings and infrastructure to adjust to ever rising sea level it is important to have a sense where it is headed. The right criteria will lead to designs that can adapt to continued rise with lower long term cost, or a better ROI, to use the business term (Return On Investment). One example I like to use is that you can build a ten story building a floor at a time, if you design the right foundation at the start. If you build a one story building and later realize you need to add more floors, you have to tear down the original to put in the right foundation for a taller structure.

Though there will be losses, there will also be great opportunities. To help change the discussion, the next time someone protests about the high cost of transitioning off fossil fuels, particularly coal and the controversial “tar sands”, say something like: “Gee, you’re right that will be expensive — and how will that compare with the cost to move every city on the coast upward and inland as sea level rises, due to the thermal expansion of seawater, the melting glaciers and ice sheets?” (See the recent news item that adapting to rising sea levels could greatly reduce the trillions of dollars of loss this century from rising sea level.)

It is too late to stop sea level from rising. The warmer ocean means the amount of ice on our planet will get smaller. We need to adapt to the inexorable rise of sea level, moving the shore inland. We also need to slow the warming as quickly as possible to slow the speed of the ice melting, slow the process of our communities and infrastructure going underwater, and slow the cost of that inevitable adaptation. (Note that “slowing” in this context is sometimes called “mitigation” though I have found that that word is poor communication.) In some ways, sticking with cheap energy might benefit our generation in the next few years. The cost of moving our cities and writing off assets will fall in large part to our children and grandchildren’s era. That may help to put the issue in perspective.

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