By Peter Weiss
Despite decades of study, climate-change researchers still can’t tell what in Earth’s atmosphere is responsible for up to 30 percent of the solar radiation soaked up there. Some scientists argue that water vapor–the atmosphere’s major sunlight absorber–takes in much more solar radiation than has been indicated by measurements and models.
Vapor doesn’t absorb enough radiation to explain the discrepancy fully, suggests a newly reported experiment from the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland.