The Climes They Are A-Changin’

Come gather ‘round, Florida

Wherever your home

And admit that the waters

Around you have grown . . .

The climes they are a-changin'

It only takes a few changes in Bob Dylan’s classic protest lyrics from the 1960s to adapt them to 21st century Florida. Of course its not rebellious youth that we in God’s Waiting Room should be worried about.

Nor is it the routine menace of hurricane season. We know the drill for that. Fill the water jugs, charge the batteries, lay in the tinned food, check the shutters, bring in the patio furniture. Pray. Been there, done that for years.

No, the worry we need to embrace is defined by two terms, feedback and tipping point, and how they translate the meaning of Dylan’s lyrics from a metaphor for social upset to a story about what’s happening at sea as the globe gets warmer.

Bluntly, the oceans are rising, and we are only now learning how soon they will rise and how high their sun fueled storms will surge and how far and deep the resulting mess will penetrate, percolate and stagnate. We do have an adequate sample from which to learn though: Andrew, Katrina, Irene, Sandy.

Until recently climate scientists were predicting a meter's rise in average ocean heights by the next century, but now, according to an article in a recent Scientific American, they find that sea ice and the arctic and antarctic glaciers sea ice helps hold back are melting faster than their most pessimistic predictions.

Although the Scientific American writer was too cautious to say so, the new uncertainty over timing leaves us to wonder: do we have decades, years, months -- or what -- to prepare for a Florida that is largely under water?

What is feedback in this context? Sea ice is white and so reflects the sun's rays back into space. When it begins to vanish, the darker waters absorb more heat, melting more ice in a cycle of "positive" feedback -- a chain reaction that feeds on itself and picks up speed. Fortunately sea ice already displaces its volume in water and thus doesn't cause the seas to rise when it melts. Except, of course, for the fact that warmer water takes up more space than colder water.

When glaciers begin to melt, the melt water trickles down and puddles beneath them as a lubricant. They slide ever more speedily, especially where there is less sea ice to slow them at the ocean's edge. Again positive feedback that, this time, dumps new water into earth's bath tub at an accelerating rate.

Skiers know about tipping points. When fresh snow piles up on slopes it balances ever more precariously. When it can't balance any more we call the result an avalanche. Greenland and Antarctic glaciers may never move that fast let us hope, but a tsunami or two is not out of the question.

What these twin concepts of feedback and tipping point tell us is that global warming will not be upon us gradually, but in fits and starts, storm after increasingly giant storm. Debating whether the warming trend is natural or man made is irrelevant. The unintended consequences of the industrial revolution are upon us and may well unfold no matter what we do. 

Remember the old Bill Cosby routine? Cosby is Noah and God speaks to him. "Noah, build an ark." Silence. "Noah!" "What!?" "Build an ark." Long pause. "What's an ark!?" What indeed.