Synopsis: The modern surface temperature record is badly flawed, inaccurate and biased from concrete/asphalt 'urban heating.'
Source here. "The IPCC cites as evidence of modern global warming data from surface-based recording stations yielding a 1905-2005 temperature increase of 0.74ºC +/- 0.18ºC. But this temperature record is known to be positively biased by insufficient corrections for the nongreenhouse-gas-induced urban heat island (UHI) effect. It may be impossible to make proper corrections for this deficiency, as the UHI of even small towns dwarfs any concomitant augmented greenhouse effect that may be present."