| Clear-cut evidences of global environmental change in Colombia are discussed
for diverse hydro-climatic records, and illustrated herein for increasing
minimum temperature and decreasing annual maximum river flows records. As a
consequence, eight tropical glaciers disappeared from the Colombian Andes
during the 20th century, and the remaining six have experienced alarming
retreat rates during the last decade. Here we report an updated estimation of
retreat rates in the six remaining glacierized mountain ranges of Colombia
for the period 1987–2007, using Landsat TM and TM+ imagery. Analyses are
performed using detailed pre-processing, processing and post-processing
satellite imagery techniques. Alarming retreat rates are confirmed in the
studied glaciers, with an overall area shrinkage from 60 km2 in
2002, to 55.4 km2 in 2003, to less than 45 km2 in 2007.
Assuming such linear loss rate (~3 km2 per year), for the near
and medium term, the total collapse of the Colombian glaciers can be foreseen
by 2022, but diverse physical mechanisms discussed herein would exacerbate
the shrinkage processes, thus prompting us to forecast a much earlier
deadline by the late 2010–2020 decade, long before the 100 years foreseen by
the 2007 IPCC Fourth Assessment Report. This forecast demands detailed
monitoring studies of mass and energy balances. Our updated estimations of
Colombia's glacier retreat rates posse serious challenges for highly valuable
ecosystem services, including water supply of several large cities and
hundreds of rural settlements along the Colombian Andes, but also for cheap
and renewable hydropower generation which provides 80% of Colombia's demand.
Also, the identified changes threaten the survivability of unique and fragile
ecosystems like paramos and cloud forests, in turn contributing to
exacerbate social unrest and ongoing environmental problems in the tropical
Andes which have been identified as the most critical hotspot for
biodiversity on Earth. Colombia requires support from the global adaptation
fund to develop research, and to design policies, strategies and tools to cope with these urgent
social and environmental threats. |