Mean annual temperature trends in the tropical Andes were determined over t
he last six decades (1939-1998), to investigate the apparent inconsistency
between the observed glacier retreat and the reported slight cooling trend
in the lower tropical troposphere after 1979. Our results indicate that tem
perature in the tropical Andes has increased by 0.10 degrees - 0.11 degrees
C/decade since 1939. The rate of warming has more than tripled over the las
t 25 years (0.32 degrees- 0.34 degreesC/decade) and the last two years of t
he series, associated with the 1997/98 El Nino, were the wannest of the las
t six decades. Temperature trends vary with altitude and show a generally r
educed warming with increasing elevation. However, despite the lower rate o
f warming, the trend toward increased temperatures is still significant at
the 95% confidence level, even at the highest elevations. Clearly high elev
ation surface stations in the: Andes do not reflect the slight cooling tren
d observed in the tropical lower-troposphere.