There are quite a few reasons to believe that the surface temperature record – which shows a warming of approximately 0.6°-0.8°C over the last century (depending on precisely how the warming trend is defined) – is essentially uncontaminated by the effects of urban growth and the Urban Heat Island (UHI) effect. These include that the land, borehole and marine records substantially agree; and the fact that there is little difference between the long-term (1880 to 1998) rural (0.70°C/century) and full set of station temperature trends (actually less at 0.65°C/century). This and other information lead the IPCC to conclude that the UHI effect makes at most a contribution of 0.05°C to the warming observed over the past century.
[Read more…] about The Surface Temperature Record and the Urban Heat Island
Gavin Schmidt is a climate modeller at the NASA Goddard Institute for Space Studies and Earth Institute at Columbia University in New York and is interested in modeling past, present and future climate. He works on developing and improving coupled climate models and, in particular, is interested in how their results can be compared to paleoclimatic proxy data. He has worked on assessing the climate response to multiple forcings, including solar irradiance, atmospheric chemistry, aerosols, and greenhouse gases.
Dr. Michael E. Mann is Presidential Distinguished Professor in the Department of Earth and Environmental Science at the University of Pennsylvania, with a secondary appointment in the Annenberg School for Communication. He is director of the Penn Center for Science, Sustainability, and the Media (PCSSM).
Caspar Ammann is a climate scientist working at the National Center for Atmospheric Research (NCAR). Dr. Ammann is interested in the reconstruction of natural climate forcings, natural climate variability, coupled modeling of natural and anthropogenic climate change, and data/model intercomparison. Dr. Ammann got his B.S. from Gymnasium Koeniz (Switzerland), his M.S. from the University of Bern (Switzerland), and a Ph.D. from the Department of Geosciences at the University of Massachusetts.
Ray Bradley is Director of the Climate System Research Center (