One last cup before the storm: climate change and coffee

The world consumes more than 300 000 cups of coffee per day, how many of those are yours?

As the second-most traded commodity, the climatic impacts on coffee would have repercussions not only in the global economy, but also in your BUBBLE OF DAILY HABITS AND PLEASURES that you took for granted… until now.

THE BEAN BELT

Every plant species has its own optimum growing conditions in terms of temperature, precipitation and soil nutrients. It just takes a glance to the image bellow to realize that the top 8 coffee producers in the world are located in tropical latitudes, where the climate conditions for the optimum growing are met.

Figure 1. The bean belt. Source: Camano island coffee

In the table below, I summarized some of the adequate climatic parameters for the ideal growing of Coffea arabica (the most common species of coffee) in its different phenological stages.

Table 1. Coffee climatic conditions. Own elaboration, References: Moraes, 1963; IBC, 1985; IARC, 1991; Carvajal, 1984;  Camargo, 1985;  Alegre, 1959; Maestri and Barros, 1977;  Haarer, 1958;  Coste, 1992

Not just the climate conditions are complex by themselves, but also the fact that a coffee plant takes three years to give its first fruit. Therefore, seasonal variability cannot be a factor that shifts from one temperature to another in order to satisfy the different phenological-stages necessities, rather it should be the mean annual values the one that oscillates around those specific temperatures.

When the thresholds are passed, a great variety of problems start to arise. For example, the fruit production of Coffea arabica drops by 10% per degree Celsius above 24°C (Nunes et al., 1968).

LOSS OF HABITAT

Climate variability is an important factor in coffee production due to the its high sensitivity. In the case of El Niño Southern Oscillation, the high temperatures and extreme storms or droughts had affected entire coffee regions in the short-term (Ubilava, 2011). Under the present climate change those amplified events are tending to increase.

The Intergovernmental Panel on Climate Change (IPCC) have compiled meticulous observations of different variables over the globe that offer a complete overview of the climatic trends. For example, the figure below shows the frequency of warm days and warm nights over a 60 years period. It is observed that the intense red areas that represent the highest increment in frequency are located in regions of high coffee production. As stated in Table 1, both night and day temperatures are very important for the plant development.

Figure 2. Frequency of warm days and warm nights. Source: IPCC

Several studies had demonstrated the strong impacts of climate change on agriculture (e.g. Pesket, 2007; Turral et al., 2011; Wiebe et al., 2015). And more specifically, the correlation of atmospheric variables and coffee production fluctuation (Gay et al., 2006; Davis et al., 2012), so a coffee crisis due to habitat loss is imminent.

PLAGUES

Coffee rust is a leaf disease with intensities that had grown recently, some affected coffee producers are: Colombia from 2008 to 2011; Central America and Mexico (2012-2013); and Peru and Ecuador (2013; Avelino et al., 2015). The fungus that causes this epidemics is a parasite that affects the leaves and eventually lead to the death of the branches, causing major crop losses. The coffee rust driving factors are mainly associated with extreme weather such as fully packed cloudy skies and high rainfall, which facilitates the plague spreading (Cristancho et al.,2015).

COFFEE SCENARIOS

The future for the coffee is more bitter than I would like. The current knowledge on coffee species and climate projections allow scientists to explore future scenarios for coffee production. For example, Davis et al.(2012) projected suitable lands for Arabica production in Ethiopia under different climate change scenarios, as observed in the Figure below, the ideal land for coffee plantations (first row) will virtually disappear under every scenario by 2080, and by 2050 will remain a few locations. As the rigor of the climatic threshold decreases, the area of coffee production increases, but it will be lands that have intermediate or marginal suitability that will ultimately impact in the farmers economy and in the coffee quality.

Figure 3. Optimal, Intermediate and marginal suitability for coffee plantations by 2020, 2050 and 2080. Source: Davis et al., 2012.

Once we understand the climatic conditions for the adequate species growth and the future projections under climate change scenarios, it’s not surprising to realize that the world has already a coffee deficit since 2014 (International Coffee Organization, 2016). More coffee is being consumed but the production can’t keep the pace.

Figure 4. Coffee deficit. Source: International Coffee Organization.

The future of our Latte looks scary, but we can definitely do something about it!

Starting from the problem’s core: CO2 emissions. Every year in the UK more than 2.5 billion disposable cups are thrown away, it requires energy to produce them and energy to get rid of them. So why don’t invest in a cool reusable cup? Or better, if you are a student, you can ask your Uni to introduce a free reusable cup in the welcome kit (I just got mine!).

If you own or work in a coffee shop, try to recycle the coffee grounds! This is a great example of company that produces clean energy with coffee grounds in London.

In the research and governance arena, it is much more to do, the solutions should be diverse and involving all sectors. Some of them are: strengthening the linkages between the actors involved in the supply and marketing chain, research entities and funding organizations; enhancing ecological control on plagues; and breeding for plague and extreme weather resistance.

So now you can go for a coffee with your friends and tell them why they should worry about climate change. Well, after all this writing, I might use a coffee-break ...See you next week!