Page 74 - Ecuador's Banana Sector under Climate Change

Figure 15
34 32 30 28
oC 26 24 22 20 18
Min Avg Max
ecuador’s banana sector under climate change: an economic and biophysical assessment to promote a sustainable and climate-compatible strategy
Monthly temperatures in Guayaquil
Jan
Feb Mar
Apr May Jun
Jul Aug Sept Oct
Nov Dec
Source: http://www.guayaquil.climatemps.com/
rainfall levels for the crop in question. For commercial bananas, the optimum daily average temperature is between 26oC and 28oC, but plants can tolerate averages between 24oC and 31oC; above and below this range, suitability would diminish.27 Generally, average temperatures below 16oC and above 33oC make commercial production unviable. Banana plants effectively shut down at temperatures above 34oC and suffer permanent damage above 40oC.
Similarly, permanent damage occurs below 10oC. Coastal Ecuador has an ideal climate for banana production and the magnitude of temperature increases projected for 2030 and 2050 will not seriously erode its suitability. Figure 15 only plots monthly averages of daily maximum temperatures; unusually hot and cool afternoons do occur but 90 percent of the variation in daily maximum is within approximately 2oC of the monthly average. In other words, one would expect the maximum daily temperature to be more than 2oC above the average maximum approximately 5 percent of the time. Temperatures that exceed the critical 34oC point are currently infrequent; at higher temperatures, the risk of exceeding
34oC would increase, but not so much as to seriously impair the capacity for commercial production. Higher temperatures, however, would shorten the time to maturation and result in smaller fruit than in the current climate. (See below for disease incidence and severity).
The projected temperature increase for the end of the twenty-first century of 3oC above current values will pose a serious threat to the commercial production of bananas. The average daily maximum temperature will exceed 34oC approximately half of the time in March and April and will present a 5 percent risk, even in the relatively cool months of July and August.
27 These values are drawn from Robinson and Gálan Saúco (2010), which is oriented towards commercial banana production (see Chapter 4: Climatic Requirements and Problems, pp. 67-88). Ramirez et al. (2011) apply a slightly lower temperature range to allow for a wider range of banana and plantain varieties and a wider range of environments (e.g. at higher elevations). Similarly, Van den Bergh et al. (2010) apply an even lower range of temperatures because of their focus on varieties adapted to the sub-tropics.
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