The Environment

Some people continue to deny that human activity affects climate change (global warming), despite evidence to the contrary. But an ingenious new study makes the case for human impact on the climate even more convincing:

Piers M. de F. Forster and Susan Solomon of the National Oceanic and Atmospheric Administration analyzed temperature data collected from more than 10,000 surface stations over the past 40 years. Using information from stations operated by certified observers for which complete weeks of data were available the researchers calculated the difference between the highest temperature recorded during the day and the lowest recorded at night, the so-called diurnal temperature range (DTR). They determined that more than 35 percent stations in the U.S. had a significant difference between weekend DTR and weekday DTR on the order of several tenths of a degree. …

The scientists tested the data set for both 28-day cycles (which could reflect a lunar influence) and random variations and found that neither could explain the findings. Because weekly cycles are rarely if ever found in nature, the observed fluctuations must therefore be anthropogenic in origin, the researchers write.