John’s Blog/Newsletter: SEA LEVEL RISE NOW

We must end the pervasive misconception that ADAPTING to rising sea level can be addressed by MITIGATION — the reduction of greenhouse gases. It is false and is only causing further delay in dealing with the inevitable adaptation that we need to be planning now.

Most people don't realize that sea level will rise for decades, even centuries, regardless of efforts to slow global warming. It is true that slowing the warming will eventually SLOW the rise in sea level — a very important goal — but it will not STOP sea levels from rising. Even if we magically stopped ALL emissions of greenhouse gases today, sea levels will still rise for at least a thousand years. We are past the tipping point.

Here are the 3 irrefutable reasons why this is now fact:

1. The oceans have already been warmed by the elevated levels of carbon dioxide and other greenhouse gases (GHG) and are now about 1.5 degrees F (0.85 C) higher than in preindustrial times. (The ocean stores heat similar to the way rocks and outdoor swimming pools stay warm long after the heat source of sunlight is removed.)
    
2. Warmer oceans directly correlate with smaller glaciers and ice sheets on the planet. The ocean will get bigger as melting ice enters the sea in the form of icebergs and meltwater. The extra heat that is already stored in the oceans means that the ice sheets and glaciers will continue to melt for centuries.
    
3. As the ocean warms there is "thermal expansion" of the water, similar to the way most materials get slightly bigger as they warm. For every degree of Fahrenheit temperature increase, average global sea level will rise approximately 2 to 3 inches.

Most importantly, higher sea level moves the shoreline inland. As a global average, the ratio is about 300 to 1 in terms of horizontal movement inland, for each unit of vertical increase. That means for each foot of higher sea level, the average coastline moves inland the length of a football field! — though the ratio varies significantly depending on topography.

We have been fooled into thinking the stable sea level of the last few thousand years was "normal." Geologic history shows this was just an intermission. Sea level moves up and down three or four hundred feet with each ice age about every hundred thousand years as I explained in the book High Tide On Main Street.

The extra heat now trapped in the Earth system means that sea level will rise far higher for at least a thousand years. It is simple physics, as fundamental as the 2nd Law of Thermodynamics. That is the new reality. The longer we avoid looking at the issue and planning for real adaptation, the more we will be investing in assets that will go underwater, literally and financially.

Planning for higher sea level is daunting. It will be disruptive. There will be losses and write offs. But as I always explain to clients or audiences, there will be great opportunities too. For everyone that loses, there will be those that gain. The sooner we start looking ahead, the sooner we will unlock our amazing creative energies to adapt and deal with inevitable higher sea level. As painful and difficult as it may be, there is a very positive opportunity here for communities, companies, investors, and individuals. Those that can see a long term fundamental trend can be better prepared. There will be entirely new cities, massive renovations to existing communities, and lots of services to address this profound new reality of "ever-rising" sea level.

Therefore we must do two things simultaneously:

1. Begin ADAPTATION knowing that rising sea levels will move shorelines inland for centuries, perhaps even sooner than the current projections suggest.
    
2. REDUCE the warming ("mitigation") to slow the extra energy that will otherwise ACCELERATE sea level rise.

We must no longer fool ourselves in believing that mitigation will STOP sea level rise. EVENTUALLY we can slow the melting ice and reverse it, but that will likely be so far in the future, that we should avoid the distraction from the task of adaptation we face NOW and for the balance of this century.  Sharing the truth about sea level rise can keep the conversations on track not only to deal with this challenge but to recognize the opportunities that are also on the horizon.