...increased precipitation in winter, more droughts in summer, and less day-to-day variability in temperature. The atmospheric concentrations of greenhouse gases...have increased because of human activities, primarily energy and agricultural practices, since the beginning of the preindustrial era around 1750: carbon...

...a 24 hour period), increased precipitation in winter, and less day-day variability in temperature. The atmospheric concentrations of greenhouse gases...since the beginning of the pre-industrial era around 17SO: carbon dioxide by about 30%, methane by more than a factor of two, and nitrous oxide by about...

...a 24 hour period), increased precipitation in winter, and less day-day variability in temperature. The atmospheric concentrations of greenhouse gases...pre-industrial era around 1750: carbon dioxide by nearly 30%, methane by more than a factor of two, and nitrous oxide by about 15%. Their concentrations...