“The Montreal Protocol is working,” says chemist Mario Molina, who shared the Nobel Prize for his work on the effects of chlorofluorocarbons (CFCs). “CFCs are a global environmental problem that is being solved by society.”
The international treaty, which opened for signature in 1987, created controls on the use of CFCs, gases used as coolants in refrigerators and to propel aerosols like hair spray out of cans. The problem was that CFCs spread out in the stratosphere, where they led to a hole in the ozone layer.
When Molina started studying CFCs in the 1970s and discovered their role in ozone depletion, each U.S. household averaged 30 to 40 spray cans. Since the late ‘90s, CFC production has all but stopped, making modern spray cans ozone safe.
The ozone layer itself? Though scientists say it will take until beyond 2050 to return to pre-1980s levels of CFCs — they take about 100 years to decompose — the amounts in the atmosphere are steadily decreasing.

Some katydids might be mutants. Discovered in the 1770s, the oblong-winged species may have undergone a genetic change. Although their ancestors apparently were green, a fraction have been found with bright colors, including yellow, orange and hot pink.
Geneticists aren’t sure what caused the mutation. Entomologists have long thought the colors are symptoms of erythrism, an anomaly similar to albinism. Scientists working with a related species at Osaka Prefecture University pointed to genetics over environmental factors as the cause.
Last summer mating trials for the oblong-winged katydid at New Orleans’ Audubon insectarium followed up on an early 1900s study. The modern entomology teams posited green as a recessive trait – good camouflage just makes them fittest for survival. Yellow and orange ones were second best, since these colors aren’t revealed till the final molt. Pink ones are least likely to survive because they are that color from birth. Pink is actually their dominant trait but makes them easy prey when young.

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