Coffee and Climate Change: Reading Past the Headlines

By Emma Sage, SCAA Coffee Science Manager

By now you have likely heard of the new scientific study published last week in the online peer-reviewed journal PLOS ONE that has sparked a flurry of doomsday headlines for coffee. The study is a collaborative effort between researchers at Kew Royal Botanic Gardens in London and the Environment and Coffee Forest Forum in Ethiopia. Since its publication on November 7th, it has been covered by the popular media with creative titles such as:

The Last Drop?; Climate Change Could Kill Off Coffee; Brew Hoo! Coffee Could Disappear by 2080, Researchers Say; Climate Change taking a toll on coffee; Try not to Panic, but Climate Change is Killing coffee; How Coffee Could become Has-Beans; Coffee Beans at Risk of Extinction; Coffee Beans Burn toward Extinction; You get the idea…

These stories cover the basic idea that coffee may be threatened by climate change, but they are also a bit confusing. What are the actual results of the study? How will the extinction of wild C. arabica affect the supply of quality coffee? How serious is the peril to our morning cup?

It is extremely important to remember that the result from one scientific paper, no matter how perfect the methodology and valid the results, does not equal a finite, absolute answer to a problem or a complete prediction of the future. It is dangerous for the popular press to sensationalize any individual scientific study as it is likely that study does not encompass the body of work on a subject. Also, some of the above headlines can lead to misperceptions about the results of the study. Scientific knowledge of any topic is an evolving and continually changing process, where small pieces of information are gathered over time and are used to build a body of work that helps us to understand a problem or phenomenon.

That being said, this article is open-access, which means that you can go to the journal web site and read or download the article for free. I encourage everyone who is interested in this topic (or the topic of specialty coffee) to do so. Currently, the article has been viewed more than 9,000 times, but only downloaded 7.41% of the time (per metrics on the PLOS ONE web site). Be empowered by knowledge and read the paper for yourself. Certainly, there may be many elements of the paper (for example, the methods section) that are not your cup of tea or as digestable as a mainstream media article. Try starting with the abstract and introduction, then moving to the results, and finally the discussion. This is an important paper highlighting one of the most critical problems facing the specialty coffee industry: loss of C. arabica genetic diversity.

For those of you who would like a bit of background on this topic, the scientific community, and now pretty much the entire world, have acknowledged that anthropogenic climate change is real and is already impacting living organisms. Since plants are rooted, they are stationary and unfortunately this gives them a slight disadvantage when climate change begins to make their living situations less than ideal. In the coffee industry we know that since coffee is a plant it will likely have some physiological or even species-level responses to changes in temperature, rainfall intensity and distribution, and other climate-related environmental changes. In specialty coffee, we have been talking about this for some time; how perhaps ideal coffee growing regions will get warmer, and how that may change the geographic distribution of those regions.

And that is exactly what this paper is showing. Their computer models mapped the range of wild C. arabica and compared that with future climate change scenarios predicted by the Intergovernmental Panel on Climate Change (the IPCC) and others for the next century revealed that within the next 70 years wild C. arabica has a high probability of going extinct. What does that mean for genetic diversity? We don’t know for sure how much unique and diverse genetic material currently exists within wild C. arabica in Ethiopia and surrounding regions. One Ethiopian PhD dissertation suggests that the genetic diversity in cultivated C. arabica only accounts for 10% of the diversity of wild Ethiopian populations (as reported on the WCR web site). However, it is likely even less than that, leaving us with much to learn from the wild genotypes. The danger is that we may never know, unless we begin to conserve these wild populations and do a thorough examination of their genetic diversity.

Why is genetic diversity important? Without writing a textbook about it, each organism’s capacity to grow, change, acclimate, and thrive, is dependent on their genetics. You can think of a genome as a sort of tool-box for organisms.  A population of organisms of the same species is made up of a group of individuals with slightly different genomes or tools at their disposal. The more diverse the population is the more differences are in the genome. This is important for long-term survival, as different individuals may have different strengths. For example, a few wild coffee plants may be very frost-tolerant due to a slight difference in their genetic codes caused by evolving in a colder than normal climate. This sub-set of the population may be the only ones to survive if exposed to a severe winter storm. Another group of wild coffee plants may produce more of a certain hormone and by chance ward off the coffee berry borer in a large outbreak. These are only two examples of what could be endless possibilities in the wild C. arabica population. The take home message here is that the more diversity that exists within a population, the more likely that population will survive exterior challenges such as climate change. Why would we (the specialty coffee industry) like to have as much C. arabica genetic diversity as possible? Because in future breeding programs this biodiversity may be used to create amazing tasting, heat tolerant, high yielding, pest and fungus resistant cultivars. But in order to access the tools we need to preserve the tool box.

What should we really know about this topic? Here are the bullets:

1)      The area of the world where coffee is indigenous has a rapidly changing climate and will change dramatically in the future due to anthropogenic climate change.

2)      Wild coffee still exists in this region that has not been conserved, catalogued, or researched for its genetic diversity and unique phenotypes, and is vulnerable to changes in climate.

3)      This study reported that the region may be inhospitable for wild C. arabica within the next 70 years, leading to the extinction of indigenous populations.

4)      Genetic diversity of C. arabica is extremely important to the specialty coffee industry, as it will be necessary to maintain an adequate tool box for breeding new coffees as part of an adaptive strategy for commercialized coffee.

5)      The climate changes predicted for this region of the world may also affect cultivated coffee in the future, which may result in a variety of other unforeseen consequences.

6)      Coffee is threatened by climate change, but we have time to act to preserve these wild genotypes. Institutions and organizations like World Coffee Research already are making progress on these important issues.

What can be done about this? What are the steps that the industry needs to take in order to preserve these wild C. arabica genotypes? The first critical step is to conserve and catalog all of the current wild materials available. There are many institutions worldwide that have small to medium sized plantations of wild C. arabica individuals from Ethiopia. These and the still indigenous coffee populations themselves need to be preserved via cryopreservation or live germplasm form in order for us to be able to access them after the climate is no longer hospitable. World Coffee Research currently has a biodiversity Project in motion to begin just this task. After the genetics have been preserved, we can begin learning from them. Analyzing their diversity and examining their physical characteristics (their phenotypes) is when we will see the true potential of the wild genomics. After we understand them and their unique qualities we will be able to use them for breeding and adapting our own favorite cultivars for future environmental conditions.

In summary, it is too late to reverse the effect of anthropogenic climate change on Ethiopia, but it is not too late to support wild coffee genome preservation.  Watch the SCAA Digital Chronicle for more info on this important and complex topic coming soon.