2020-04-01 Smithsonian Magazine

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YOU’VE GOT QUESTIONS. WE’VE GOT EXPERTS

108 SMITHSONIAN | April 2020 Illustration by Traci Daberko

F

OR THUNDERSTORMS and resul-
tant lightning to occur, there must
be rising currents of warm, moist
air. Deep in the Arctic and Antarctic,
there is only cold, dry air, which does
not rise, and thus cannot form thunder clouds, says
Douglas Herman, senior geographer at the Nation-
al Museum of the American Indian. But as climate
change brings moister, warmer air to the area, light-
ning is increasing and causing fi res in the boreal for-
ests where that used to be rare.

Q: My barber sends hair clippings to orga-
nizations that use them to soak up oil spills.
Does that work? What other tricks are used?
Claire Bugos | Evanston, Illinois

THE MOST COMMON methods for cleaning up oil
spills are dispersing, in situ burning or skimming.

Chemical dispersants break up the oil slick into

droplets, which mix into the water column or are

broken down by microbes. That option, used in

the 2010 Deepwater Horizon oil spill in the Gulf of

Mexico, can be harmful to marine life, says Andrea

M. Quattrini, research zoologist and curator of an-

thozoa at the National Museum of Natural History.

For the other approaches, a boom fi rst concentrates

the spill in one area. The oil is either set on fi re, or

is removed from the surface using a device called a

skimmer. There are diff erent designs and methods,

including using suction or gravity to move the oil in

storage tanks. Hair clippings can be used to make the

containment booms , but are not widely deployed.

Q: How does a coff ee brand earn the label

“bird-friendly”?

Anonymous

COFFEE PLANTS can be grown either in the under-

story of tree canopies, a practice that helps sustain

migratory bird habitat, or in direct sunlight, which

drives deforestation and leads to less diverse habi-

tats. To conserve habitats for overwintering migra-

tory bird populations, Smithsonian’s Bird Friendly

certifi cation eff ort, started in the late ’90s, supports

farmers who opt for shade-grown coff ee, says Scott

Sillett, who heads the Smithsonian Migratory Bird

Center. At the moment, 45 farms are participating in

the program, primarily in Central and South Amer-

ica. To be certifi ed, a plantation must include for-

est land that has not been cut for at least ten years,

support ten native tree species, provide 40 percent

shade coverage and also be USDA-certifi ed organic.

Q: Will cli mate change have any eff ect on all

the “space junk”—like outdated satellites or

spent rocket stages—currently in orbit?

Don Maddox | Pasadena, California

WHEN SCIENTISTS discuss the greenhouse eff ect,

they’re usually talking about changes in the tropo-

sphere, the lowest part of Earth’s atmosphere. The

thermosphere, where most of these man-made or-

biting objects are located, is also experiencing an

increase in carbon dioxide. But at that level, because

the atmosphere is much less dense, carbon dioxide

behaves diff erently, says Martin Collins, curator of

the civilian applications satellites collection at the

National Air and Space Museum. Instead of trap-

ping heat, the CO 2 releases heat into space and chills

this upper layer of atmosphere. As a consequence,

the thermosphere contracts, resulting in less atmo-

spheric drag or friction on such objects.

Q: I’ve heard lightning rarely strikes in

the Arctic. Why is that?

Carter Matthew | Boston

Text by Anna Diamond

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