Climate information
Due to the influence of the sea in the region, temperature fluctuations are small and rainfall is by far the most important meteorological variable. Precipitation is influenced by the migration of synoptic features and the mean climate strongly reflects the annual cycle of these features. Rainfall means are strongly controlled by topographic characteristics and also by energy balances controlled at mesoscale level by land cover types.
Central America disasters associated with extreme weather are manily droughts, in the Pacific area, and floodings, which occure in floodplains with corresponding heavy and intense rainfall associated to tropical storms or hurricanes.
Climate projections for Honduras, Costa Rica and Nicaragua show a common pattern which, according to the pessimistic scenario of HadCM2-IS-92a, varying averages of increasing temperatures and decreasing precipitation are expected.
Climate projections to year 2100 for TroFCCA countries in Central America according to HadCM2-IS-92a (information from respective National Communications to UNFCCC).
Information Frame |
Temperature ºC |
Precipitation (%) |
Cloudness (%) |
|---|---|---|---|
|
Honduras |
||
I |
3.3 |
-29.8 |
-10.9 |
II |
2.7 |
-28.4 |
-11.4 |
II |
3.7 |
-36.6 |
-15.6 |
IV |
3.3 |
-35.7 |
-17.2 |
|
Nicaragua |
||
Pacific |
3.7 |
-36.6 |
-15.6 |
Caribbean |
3.3 |
-35.7 |
-17.2 |
|
Costa Rica * |
||
Region I |
0.6 a 3.8 |
-3.3 a -63.4 |
17.8 a - 22.9 |
Region II |
0.5 a 3.2 |
-4.4 a -8.8 |
14.5 a -23.9 |
Region III |
0.6 a 3.5 |
-0.4 a -46.3 |
-0.5 a -23.8 |
* Region III is not reported its territorial coverage is too low for HadCM2 spatial resolution.
Increase in dryness can be predicted from increasing temperature and decreasing deprecipitation.
Extreme events
Honduras, Nicaragua and Costa Rica are affected periodically by drought and floods, accompanied by disasters with different intensities due to local characteristics.
Droughts
Droughts have ocurred either linked to an ENSO phenomenon or to an alteration of the path of Inter-Tropical Convergence Zone which influences the displacement of trade winds over land and thus the occcurrence and distribution of rainfall. As an example of impacted areas, the following map shows the 2001 drought impacts in the region.
Figure 1: Areas impacted by drought in 2001 in Central America.
Source: ECLAC, 2002.
The impacts of the drought in 2001 affected mostly small subsistance farmers. Many of these farmers could not follow the usual strategy consisting in selling their labour in the coffee sector due to the crisis in this crop sector price. The energy sector was vulnerable due to the diffuse dependance on hydropower. Reduced storage capacity due to sedimentation (associated to land use management practices) and the shortfall in precipitation due to drought caused a reduction in hydroelectricity production which required increase in energy import or higher cost thermal production.
Extreme precipitation
They are one of the main causes of floodings in Central America (though land use and cover might play a partial role while mitigating by "absorbing" rainfall up to a certain rainfall threshold). Extreme precipitation events occurr in the context of a hurricane or a tropical storm which take place mainly from June to November. Historical hurricane trends in the Caribbean shows a wide spatial variability, frequency, size and intensity as shown in the graph below. Although an increase in frequency is expected, a recent scientific publication (Kerry, 2005) confirmed a link between increase in sea surface temperature and intensity of hurricanes (rather than frequency).
Frequency of hurricanes in Central America for the period 1944-1999.
Source: Pielke et al., 2003.
Impacts and adaptation to climate change and extreme events in Central America
A revision of Climatic Models and the Projection of Scenes of Climatic Change in Central America