Climate reconstruction from subsurface temperatures demonstrated on example of Cuba

Temperature-depth records from more than 30 boreholes from Cuba were inverted to assess the ground surface temperature (GST) history. A simple step-model of ground warming originally proposed [Global Planet. Change 97 (1992) 325] has been re-examined by applying a more complex inversion technique. A general climate-warming scenario of the past several centuries is proposed. Combining borehole temperature logs with meteorological surface air temperature (SAT) records the baseline temperature (pre-observational mean (POM)) was calculated. All obtained POM values are negative and they vary from -0.09 to -9.01 K with a clear preponderance values ranging between 0 and -2 K, relative to the 1950-1980 reference mean temperature, This indicates characteristic colder conditions before year 1880, the beginning of the long-term SAT recording. The observed warming can be related both to the widespread temperature changes in the tropical Atlantic region as well as to the environmental effects of extensive deforestation which accompanied the land-use development in Cuba. The average warming rate for Cuba for the last about 100 years amounts 2.2 +/- 0.5 K and is in good agreement with similar values reported for other Caribbean islands. (C) 2001 Elsevier Science B.V. All rights reserved.