I’ve been slow to say anything about the Gulf of Mexico situation because, in all honesty, words simply fail to express my disgust. Dwelling on blame doesn’t seem reasonable because in an economy that pigs out on oil the way we do something like this seemed inevitable. The cleanup is going to be long and difficult no matter what. But one angle that seems to have been lost in furor is the critical role that the Gulf of Mexico has in bringing life to North America and Europe in the form of warmth and rain. A tremendous slick of oil has the potential to change the climate in ways that are, at the very least, worth keeping an eye on.
The Mississippi-Missouri-Ohio river systems are over 90% contained. Water evaporates in the Gulf, swirls over the continent, and falls as rain through the vast center of North America. Very little water comes in over the Rockies and the prevailing winds keep clouds from the east away, meaning that it all comes up from the South.
Similarly, the warm water bubbles up into a river that passes the Strait of Florida and becomes the well-named Gulf Stream, making Europe much more habitable than its high northerly latitude would suggest. This one shallow sea is responsible for a tremendous amount of life in the Northern Hemisphere.
How might a film of oil in place over the next few years change this? The process of bringing the water of life from the Gulf has two distinct phases that might be affected.
First, sunlight is absorbed by the water which has now become darker and more turbid (cloudy). If there is any net change in the amount of heat taken up by the water of the Gulf, it should reasonably be higher – that is, the water itself is likely to become hotter or stay the same.
The other process is one of evaporation, where the hot water boils up into the air on its way to becoming a sweltering Midwestern summer or, when conditions are right, a dark thunderstorm. We can expect that a thin film of oil bubbling up from underneath will only slow the rate of evaporation, if it makes any change at all.
That leave us with four possibilities for the near future:
Absorption increases but evaporation stays the same. This would make for a hotter Gulf. In this scenario, there is more fuel waiting for a hurricane that may just have the low pressure and turbulence to mix things up and encourage evaporation in the way a calm sea cannot. The amount of warm water going to Europe also would increase, and effect that would probably only be noticed if it continues for many years.
Absorption increases and evaporation decreases. This is the same as above, but potentially much moreso. The Gulf could become much hotter than we’ve ever seen and have the potential to fuel very large storms that are catastrophic.
Absorption remains the same but evaporation decreases. That would mean less water moving into the air and the potential for drought throughout the farm states of the Midwest lasting for years.
Both remain the same. Obviously, there would not be any net change.
Given these four possibilities, it seems that if the net effect of a sea darkened by oil is a hotter sea that may not be able to find its equilibrium easily. The climate would, primarily, become a bit more chaotic and act outside of normal bounds. There is at least some potential for drought if the evaporation is slowed significantly. The changes may be large or small – we can’t say until we see how important the processes of water and energy in the Gulf are affected.
What will happen because of this terrible oil spill? Away from the human drama of cleaning and blaming, preening and shaming there is at least the potential for a serious change in the life of two highly populated continents. The Gulf of Mexico is that important to civilization as we know it. We can’t predict exactly what will happen, but there are boundaries based on what we know can happen. None of it is good.
There could be a storm coming, so fasten your seatbelts. Better yet, just stay out of your car and seek shelter. – we’ll all burn a bit less petroleum.