Human Activity Blamed for Atmosphere Changes
From Times Staff and Wire Reports
Human activity may account for 80% of a two-decade, several-hundred-foot increase in the height of the tropopause -- the boundary between the atmosphere’s Earth-hugging lower layer and the ultraviolet radiation-absorbing middle layer, scientists reported in the July 25 issue of the journal Science.
New computer models show that ozone depletion in the stratosphere, or middle layer, and increased greenhouse gases in the troposphere, or lower layer, which can occur through the use of aerosol sprays and the burning of fossil fuels, may be partly responsible for the increase.
