Plankton Cause Hurricanes! Urgent Action Required!

Guest Post by Willis Eschenbach

When people say that we understand the unbelievably complex climate system well enough to project scenarios out a hundred years, I point out that new things are being discovered every week. The latest scientific finding is that plankton cause hurricanes. I know it sounds like a headline in The Onion, but there it is.

Figure 1. Phytoplankton (ocean) and Normalized Difference Vegetation Index (land), 3 year average. Data from SeaWIFS satellite. Green in the ocean indicates the presence of chlorophyll-containing plant plankton (phytoplankton). Image Credit NASA

The study hasn’t been published, but the publishers (AGU) have this to say: [updated link here]

Ocean’s Color Affects Hurricane Paths

AGU Release No. 10–25, 13 August 2010

For Immediate Release

WASHINGTON—A change in the color of ocean waters could have a drastic effect on the prevalence of hurricanes, new research indicates. In a simulation of such a change in one region of the North Pacific, the study finds that hurricane formation decreases by 70 percent. That would be a big drop for a region that accounts for more than half the world’s reported hurricane-force winds. …

In my opinion, the folks who wrote the headline missed the boat when they say that the color of the ocean affects hurricane paths. If their description of the study is correct (not yet published study, but description by publisher) what the study indicates is that the amount of microscopic life in the ocean affects hurricane formation. Or in other words, plankton cause hurricanes. I wonder if New Orleans residents can sue the wee timorous planktonic beasties for damages from Hurricane Katrina?

The mechanism which they propose for this increase in hurricane formation where plankton are present seems quite reasonable to this life-long sailor …

In the no-chlorophyll scenario, sunlight is able to penetrate deeper into the ocean, leaving the surface water cooler. The drop in the surface temperature in the model affects hurricane formation in three main ways: cold water provides less energy; air circulation patterns change, leading to more dry air aloft which makes it hard for hurricanes to grow.The changes in air circulation trigger strong winds aloft, which tend to prevent thunderstorms from developing the necessary superstructure that allows them to grow into hurricanes.

There’s another mechanism known to be at play as well. This is that certain common phytoplankton produce a chemical called dimethylsulfoniopropionate. Since no one can pronounce that correctly, it is always called DMSP. DMSP is an precursor chemical for the formation of aerosols that eventually become cloud nuclei. This increases cloud formation. So we have plankton helping build the clouds that cool the ocean surface.

The presence of plankton in the water warms the ocean surface. And clouds and hurricanes cool the ocean surface. What is the net effect of these two inter-related but opposed plankton-caused phenomena? Unknown, even as to sign. How does this net effect change, either annually, decadally, or longterm? Again, unknown.

Plankton emit chemicals that control the clouds in the skies, who would have guessed? And who would ever have thought that plankton would have the power to affect the formation of the world’s largest natural heat engine, tropical hurricanes? Talk about having your hand on the heat-loss throttle, control of hurricane formation by plankton has the smallest of life controlling the huge power of the largest of climate phenomena. How strange is that?

I do not bring up this study to draw any scientific conclusions from it at all. It’s far too early days for that, the study is not even published.

I bring it up to illustrate the awesome complexity of the climate, and how little we truly understand the often bizarre intricacies of how it works. Next time someone says that computers can project their tinkertoy scenarios out a hundred years, remind them that we just found out about the plankton and the hurricanes …