Solutions for the future
Coffee rust in the future
The time of emergence of the climate change signal (the date
at which the climate state moves out of its historical range of
variability), in tropical areas, for mean annual temperature will
possibly be reached within the current decade for Central
America (Hawkins and Sutton 2012). Historical climate trends
for Central America (1961–2003) have already shown an increase
in maximum and minimum temperatures (0.2–0.3 °C/
decade), and a decrease/increase in the frequency of cool/
warm days and nights respectively, combined with no trend
in total annual rainfall but increased precipitation intensity
(Aguilar et al. 2005). Other studies, also using station data
but interpolated over forested areas, agree with these temperature
trends and find a correlation between the temperature
anomaly due to ENSO development and an increased spatial
trend in these anomalies, spanning throughout Central America
(Malhi andWright 2004). Future climate scenarios show a
drying trend over most of the region that is highly consistent
across global climatemodels (Neelin et al. 2006) and emission
scenarios, with precipitation anomalies showing less agreement
in signal across models for southern countries (Panama
and Costa Rica) (Imbach et al. 2012). The largest increase in
temperature is expected between March and August (with a
relatively large level of agreement across climate models)
along with expected increases in the frequency of warm days
and nights (in agreement with recent observed trends)
(Biasutti et al. 2012). Precipitation reduction is also expected
to be greatest between March and August and particularly
between June and August (following a similar North–south
uncertainty gradient as the annual anomaly) (Biasutti et al.
2012) resulting in a stronger and longer mid-summer drought
under future climate scenarios for Central America (Rauscher
et al. 2008). In Colombia, the situation with regard to rainfall
is the opposite, and weather modelling indicates that the Pacific Decadal Oscillation (PDO) is causing the start of a
30 years period where La Niña events, associated with rainier
than normal conditions, will be more frequent (Laing and
Evans 2011).