Eight of the 15 Colombian glaciers have been lost and - Eco

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Transcript Eight of the 15 Colombian glaciers have been lost and - Eco

Third Western Hemisphere Migratory Species Initiative
Adapting habitats of importance to migratory species
in the face of climate change
Climate change challenges to mountain ecosystems
in the Tropical Andes
Luis Germán Naranjo
Ecoregional Conservation Director
WWF Colombia Program Office
Asunción, 25 July 2008
Climate change has arrived in Latin America….
•
Eight of the 15 Colombian glaciers have been lost and the rest have
retreated approximately 20 meters during the last half century.
•
In the tropical Andes of Peru 10 glaciers, monitored since 1932, retreated
between 590 m and 1910 m through 1994 (Ames, 1998).
•
On the Antisana glacier in Ecuador mass balance measurements indicate
an average negative trend of 600–700 mm yr−1 during the last decade.
•
In Bolivia the Chacaltaya glacier lost 60% (93%) of its ice volume between
1940 and 1983 (Francou et al., 2000, 2003).
Photo: Jorge Lotero
Rising temperature may be the most likely candidate to explain
glacier retreat over the last few decades, but glaciers may also
suffer from a negative mass balance due to negative trends in
precipitation and/or enhanced absorption of solar radiation due to a
decrease in cloudiness.
• Within the last decade, annual rainfall in the Colombian páramos
has decreased up to 2 mm/ year.
• It is estimated that 75% of the páramos will be lost during the next
century.
• Observational evidence indicates a general tendency toward
slightly drier conditions for southern Peru and western Bolivia.
• Precipitation amounts have changed little over the last 45 years,
to the north, although there are several reports which indicate a
precipitation increase on a regional scale to the east of the Andes,
(Vuille et al., 2000a), and NW-Argentina (Villalba et al., 1998).
•
Relative humidity in near-surface levels has increased by 0–2.5% decade−1
between 1950 and 1994.
•
The observed increase in relative humidity is also apparent in model
simulations, but on a regional scale the results between model and
observations vary significantly.
•
This increase in relative humidity shows that the absolute humidity increase
is larger than what could be expected from a temperature increase alone.
• Temperature shows an average warming of 0.09–0.15 ºC decade−1
between 1950 and 1994 with most of the warming taking place after
the mid 1970s.
• Near-surface temperature has increased significantly throughout most
of the tropical Andes, and varies markedly between the eastern and
western Andean slopes.
• Lower elevations west of the Andes have experienced the greatest
warming, while the warming to the east is only moderate below 1000
m. Higher elevations show higher warming on the eastern than on the
western slopes.
Climate models, downscaling and uncertainty in
complex landscapes
Miroc3_2_hires Model
SRES A1B
Precipitation
ECHAM A2
Δ mm
2010 - 2029
2050 - 2069
2080 - 2099
Humidity
ECHAM A2
Δ %
2010 - 2029
2050 - 2069
2080 - 2099
Temperature
ECHAM A2
Δ ºC
Δ %
2010 - 2029
2050 - 2069
2080 - 2099
Climate-related risks and impacts in high Andean ecosystems
• Extreme droughts  reduction of food production, increased fire
intensity and frequency.
• Extreme rainfall  floods and landslides, increased erosion,
damage to infrastructure, losses of human lives,.
• Glacier retreat  decrease of available water for human
consumption, hydropower, and irrigation. Increased risk of “natural”
disasters.
• Changes of distribution patterns of plants and animals 
disturbance of food chains, expansion of ranges of disease vectors
Source: Robledo 2007
• In Ecuador, a 1oC increase and a 15% reduction in rainfall would increase
the current deficit of water availability during the dry season.
• In Colombia, 84% of the municipalities and 91.3% of irrigation districts
would suffer water shortages and 1/3 of Andean agricultural lands will be
affected.
• Water level of the dams generating hydropower would be compromised
affecting 78% of Colombia and Peru and 70% of Ecuador and Venezuela.
• 34% of current supply of potatoes in Ecuador will have to be replaced by
imports or a 38% increase of cultivated land
Source: Soto 2007
Cristal balling: ecological
responses to CC
• Warming and drying trends may
increase the frequency and intensity
of fires in the paramos and the
downward contraction of cloud
forests.
• The downward expansion of paramos,
as we know them, may be prevented
by the slow growth of dominant plant
species and reduced humidity.
• Range contractions of invertebrate
populations may affect the
distributions of their predators even if
they are more resilient to climate
change.
• Changes in the floristic composition
and phenological patterns along
elevational gradients are likely to
disrupt altitudinal migrations.
• Cascading effects of the disruption of
species assemblages are likely.
Loss of very humid
Andean forests
Drier paramos
Drier sub Andean
forests
Loss of Andean forests
and humid paramos
2008
2030
Expected changes in life zones in the Eastern Cordillera Real
2060
Climate trends and migratory birds:
Baird’s Sandpiper (Calidris bairdii)
Climate trends and migratory birds:
Cerulean Warbler (Dendroica cerulea)
To ensure the maintenance of biodiversity, and the provision of
ecosystem services for human populations in high Andean
ecosystems, it is essential to develop climate change mitigation
measures, adaptation strategies to its potential impacts, and increased
public awareness to face the challenge of living in a fast changing
environment.
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