Model simulations of changes in radiative forcing (W m-2) from 2000 to 2100 for all greenhouse gases (panel a, top left) and short-lived species only (panel b, bottom left). The short-lived species (sulfate, black carbon, tropospheric ozone, and organic carbon) exhibit a northern mid-latitude maximum. The right-hand panels show the simulated time series of summer average surface air temperature changes (°C) relative to the year 2001 for the continental United States, showing the increasing contribution from short-lived species after the year 2030 (panel d, lower right). Credit: H. Levy II, M . D. Schwarzkopf, L . Horowit z, V. Ramaswamy, and K . L . Findell, NO A A/Geophysical Fluid Dynamics Laboratory (reproduced from Journal of Geophysical Research with permission from the American Geophysical Union).