Scientists examined data over a 24-year period from three satellites measuring incoming sunlight against the amount of radiation reflected back into space from the surface of Earth. They discovered that the brightness of Earth is dimming, and the Northern Hemisphere is darkening more than the Southern Hemisphere. Scientists hypothesize that 1) increased warming in the Northern hemisphere from loss of highly reflective sea ice may be partially responsible, and 2) fewer reflective aerosols in clouds in the Northern Hemisphere mean more sunlight penetrates the atmosphere (recent volcanic activity and the Australian bushfires in the Southern Hemisphere has led to more cloud-bound aerosols).

Why this is matters: If less sunlight is reflecting off clouds and the surface in the Northern Hemisphere, more heat will melt more ice, furthering global warming.

What the experts say: Because of the imbalance in reflectivity, “the whole circulation of the climate will shift in order to transport energy from the hemisphere that has a surplus to the one that has a deficit,” says Brian Soden, a University of Miami professor of atmospheric science. This could influence ocean currents and the location of rainfall bands, which can have ramifications for water availability.

A population of invasive smallmouth bass in Little Moose Lake in New York have genetically outmaneuvered the 20-year culling campaign by a group of Cornell University scientists. Genetic tests revealed that the overpopulating fish have evolved to grow faster and spawn younger. The new adaptations let them reproduce before the scientists take their twice-yearly lake cruise to electrically cull and remove the fish. The lake’s bass population is thriving at larger numbers than ever.

How this works: Scientists sequenced DNA samples of the fish and found that the genes of the chromosomes involved in growth rate and reproduction timing were “wildly different” from those in tissue samples taken from Little Moose bass preserved before the electrofishing began, says Liam Zarri, a molecular ecologist at the Smithsonian National Zoo and Conservation Biology Institute. Individual bass with genes that lead to late sexual maturity and slow growth didn’t survive to reproduce before the shock treatments. Instead, the bass that were genetically predisposed to live fast, reproduce early, and die young were more likely to spawn.

What the experts say: The timing of the cullings is fueling the fishes’ genetic adaptation, so varying the culls’ timing and frequency could slow the rapid evolution, says Stephanie Green, an ecologist who wasn’t involved in the research. The Cornell scientists say they’re actively considering such alternatives. —Andrea Tamayo, Newsletter Writer