Page 75 - Ecuador's Banana Sector under Climate Change

chapter 3: climate change in ecuador and its impact on banana crops: an overview
4.2.2 Precipitation
Most IPCC climate models forecast that surface sea temperatures will increase more in the eastern equatorial Pacific region than in the western Pacific region. The climate, therefore, would become slightly more El Niño-like.28 The net result would be more rainfall along the coast of Ecuador and northern Peru. The central IPCC forecast for Coastal Ecuador for 2080-2099 (relative to 1980-1999) is for an increase of about 0.5-0.7 mm/day of precipitation in the months of December, January and February and an increase of about 0.7 to 0.9 mm/day in the months of June, July and August. Coastal Ecuador currently has a rainy season from late December through mid-May; otherwise, there is almost no precipitation. Average monthly rainfall for December to February is 160 mm and for June to August,
4 mm. The end-of-century changes that are forecast would increase the current averages to 178 mm and 28 mm (using the mid-points of the forecast ranges
and 30-day months).29 Increased rainfall would potentially be more beneficial than harmful for Ecuador’s banana production. If the increase comes in the form of occasional violent downpours, then harm would be probable. If the increase is distributed evenly as slightly more rain than occurs currently, it would be beneficial, since it would somewhat reduce the reliance on irrigation in the drier months.30
The reduction of Andean glaciers and snow fields means that less precipitation is stored as ice and snow. A reduced glacial buffer increases water discharge during the rainy season, stressing existing river and water management systems. Increased discharge in the rainy season means reduced discharge in the dry season, which poses a major threat to water supplies in the Sierra. The coastal region is not as exposed to these dry season risks, but greater discharge during the rainy season would likely require greater attention to water management, particularly in ensuring drainage and flood control.31
4.2.3 Disease
In Ecuador, higher temperatures potentially will make conditions slightly less favourable for BS, but this may be offset by higher rainfall and higher relative humidity. The influence of higher-than-expected rainfall on BS-favourability may increase the duration of the rainy season, resulting in more months with an average relative humidity exceeding 80 percent. Under all IPCC scenarios, Ecuador will remain at least proportionately BS-favourable.32
28 “These background tropical Pacific changes can be called an El Niño-like mean state change (upon which individual El Niño-Southern Oscillation (ENSO) events occur).” IPCC (2007: 779).
29 IPCC rates these forecasts as likely; that is, as having at least a 66 percent chance of being correct. The prediction for December to February is more likely than the June to August forecast, but the potential is not sufficient to merit the rating ‘very likely’ with a 90 percent chance of being correct.
30 It may require, however, more fungicide use.
31 With regard to Andean glaciers and water resources, see Chevallier et al. (2011), Rabatel et al. (2013) and
Bradley et al. (2006). Arias-Hidalgo et al. (2013) focus on challenges facing the Guayas River Basin.
32 Ghini et al. (2007) examine BS-favourability relating to Brazil. Given the high-resolution climate projection data, a similar study could be produced in relation to Ecuador.
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