Using the available evidence, Peter Baker, James Alden and Paul Baranowski* look at how the climate has been changing in Colombia’s coffee zones, and how the industry there is responding
From Cenicafé’s meteorological station network, which covers a range of elevations in coffee zones, we can compare pre-1980 average temperatures to recent years (2006 to 2017). A clear increase of about 1.2°C (~ 0.3°C/decade) can be seen.
In terms of elevation, this suggests that the lower limit for coffee growing has risen by about 200m over the past 40 years. Cenicafé publications from the 1970s onwards refer to the coffee zone being between 1,000m and 2,000m above sea level with an optimal range from 1,250m to 1,600m, from where the best yields are obtained.ⁱ
Optimal range is changing
Because of recent warming, it seems likely that the optimal range now lies between 1,450m and 1,800m and even above. As far as quality is concerned, the Cup of Excellence results bear this out: of all 327 finalists between 2005 and 2018, only 8 per cent had elevations below 1,450m whereas 58 per cent were between 1,450m and 1,800m, with 34 per cent above 1,800m.
For precipitation, the picture is less clear. Rainfall is inherently variable; hence it is always difficult to detect a consistent signal emerging from the noise. For instance, two stations in the Caldas coffee zone – Cenicafé and Naranjal – are only 7km apart; over the period 1971-2010, the former shows a decline of 6mm/ year whereas the latter a rise of 7mm/ yr.ͥⁱ Overall, it is likely that Colombia is getting wetter and that the extra rain falls in heavier downpours, which is a global trend of humid regions; currently though it is a poorly researched area in coffee zones.
The sunshine problem
In the Andes, around the altitude where rainfall is at its maximum (about 1,500m above sea level), sunshine hours have been declining by −3.7 to −8.5 per cent per decade.ⁱⁱⁱ The reason for this is increased cloud cover, which is likely also the reason why minimum rather than maximum temperatures have risen significantly there.
The Coffee Farmer’s Manual produced by Cenicafé states that light levels below 1,700 hours/year are inadequate for high production.ⁱᵛ The decline has been substantial in recent years; for instance, the Cenicafé station sunshine average for years 1942 to 1993 is 1842 hours, whereas the mean of the years 2006 to 2017 is only 1,491 hours – a remarkable 19 per cent fall.
Generally, it seems that in much of the coffee lands (1,200m to 1,800m) these levels are not reached in most recent years meaning that maximum obtainable yields may be depressed by as much as 50 to 60 per cent in some years.
Temperature fluctuations follow quite closely global values, showing the extent to which Colombian coffee is at the mercy of global weather patterns.ᵛ
During El Niño events, extremes are becoming more extreme: on 7 February 2016 the Cenicafé station (1,310m) recorded a 75-year record maximum of 36°C, extremely high for Arabica – temperatures above 34°C can cause flower abortion in a few hours.
Although such extremes are still a rare event, this must be a concern because part of the country’s coffee species collection is maintained at this altitude. On the other hand, a dramatic La Niña event in 2010-11 reduced flowering and the accompanying low light levels during that event led to weakened plants which were further affected by low soil nutrition because conditions did not permit farmers to apply routine fertilizer treatments.■ C&CI
*The authors work with Climate Edge www.climate-edge.co.uk, which is currently engaged on two climate-related projects in Colombia with Innovate UK
i Cenicafé (1972) Avances Técnicos No.015
ii Mayorga et al (2011) IDEAM– METEO/001-2011 nota técnica
iii Ruiz et al. (2012) DOI 10.1007/s10584-011-0228-0
iv Manual del Cafetero Colombiano (2013) Tomo 1, FNC-Cenicafé
This extract is from an article that first appeared in the May’19 issue of C&CI, click on subscribe now if you wish to read the article in full and other informative articles in the current and future issues of C&CI.