Climate reconstruction from subsurface temperatures demonstrated on example of Cuba

Temperature-depth records from more than 30 boreholes from Cuba were invert ed to assess the ground surface temperature (GST) history. A simple step-mo del 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 tempe rature (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 cha racteristic colder conditions before year 1880, the beginning of the long-t erm SAT recording. The observed warming can be related both to the widespre ad temperature changes in the tropical Atlantic region as well as to the en vironmental effects of extensive deforestation which accompanied the land-u se development in Cuba. The average warming rate for Cuba for the last abou t 100 years amounts 2.2 +/- 0.5 K and is in good agreement with similar val ues reported for other Caribbean islands. (C) 2001 Elsevier Science B.V. Al l rights reserved.