
Tropical Storm Issac Growing
This image from NASA's GOES-13 satellite shows two active cyclones in
the Atlantic -- tropical storm Issac, which will likely be a hurricane
by late Thursday, and a new tropical depression.
NASA
Hurricanes form in warm tropical waters, drawing strength from the heat of the ocean surface — that’s why they are expected to worsen as sea surface temperatures increase. But if we could cool them off, they may chill out and decrease in strength. Cloud seeding the areas in front of their path might be a way to do this, a new study says.
The
idea is to target marine stratocumulus clouds, which cover about a
fourth of the world’s oceans. Reflecting more light away from the sea
surface would theoretically prevent it from getting as warm. “Then there
will be less energy to feed the hurricanes,” said Alan Gadian of the
University of Leeds.
In this concept, a fleet of drones at or near the surface could spray
sprinkles of seawater droplets, some of which would rise into the
atmosphere. The increased droplet concentration would make the clouds
thicker, causing them to last longer and reflect more sunlight, the
Leeds scientists say. By the way, this is the same basic technique
Beijing officials used to create rain during the 2008 Olympics.
The scientists ran calculations and found this cloud-brightening
technique could decrease the sea surface’s temperature by a few degrees,
and thereby drop hurricanes’ strength down an entire category.
One major downside: Cloud seeding interferes with the atmosphere’s
natural cycles, so laying a path for new clouds over the ocean would
draw moisture away from nearby areas. Like, for instance, the Amazon
rainforest. Any future cloud seeding efforts would have to be very
careful.