Evidence of climate warming from underground temperatures in NW Italy

The ground surface temperature (GST) history in NW Italy was reconstructed for the last three centuries by means of temperature-depth data recorded in a borehole in 1982. The results indicate relatively warmer periods in the 18th century and at the end the 1970s. A more recent set of underground tem perature data was recorded in 1996. The comparison with the earlier thermal logging shows an evident temperature increase in the uppermost 80 m. Two d ifferent inversion techniques yield a subsurface temperature increase of 0. 8-1.0 K since the 1980s. The inferred climatic model is consistent with the air temperature variations recorded at the Genoa University meteorological station. (C) 2000 Elsevier Science B.V. All rights reserved.