Shaving Cream Prank or Ship Tracks?
Oh, the weather outside is frightful ... or is it? Stroll through this collection of winter wonderlands -- with the occasional reminder of snow's inconvenience thrown in, just to keep us honest. Here we see a tree-lined road in Saxony, Germany.
Snow can bog down trees while still looking beautiful. Neat trick!
Wan M. Iktab
Would this bench in Japan be unoccupied on a warm spring night? Probably not.
Bas Slabbers Photography
Being human, we're not easily swayed to take cover during a storm, even one as bad as this one in the Netherlands.
Of course, children, such as this Canadian boy, are even worse than grown-ups about coming in from the cold.
Sledding. Skiing. These are fun modes of winter locomotion. But driving? Maybe not so much!
I could have sworn I saw this same foamy pattern the other day while cleaning my oven, but no, this is NASA’s latest image of ship tracks over the northeast Pacific Ocean near the coast of Oregon and Washington. The microscopic particles, or aerosols, in ship engine exhaust make good seeds for water condensation under the right atmospheric conditions, creating the clouds in their wake. Years ago it was debatable whether these anthropogenic clouds were helping to cool the Earth or warm it. Last I heard the verdict was that the clouds trap more heat in the lower atmosphere, thereby warming things up.
But the NASA Earth Observatory folks report a new twist to this:
The aerosol particles may be natural—such as desert dust or sea salt—or artificial, including the particles emitted by ships. The particles in ship exhaust are more abundant than natural airborne particles such as sea salt, so they generate more and smaller cloud droplets. Because of this, ship tracks tend to be brighter than other clouds. Water droplets are essentially tiny spheres, and a smaller sphere has a greater surface-to-volume ratio than a bigger sphere. In other words, a littler droplet has a greater surface area, relative to its volume, than a bigger droplet. The greater surface area means more sunlight reflected back into space.
That means ships can have two completely opposite effects on climate. One one hand they are releasing tons of climate warming carbon dioxide by burning fossil fuels. On the other hand, they are helping to reflect more sunlight back into space, which keeps some solar energy from being captured by the oceans and atmosphere.