By Yessenia Soto, Rainforest Alliance
“Global warming and extreme weather events are disrupting the entire production schedule, pruning, flowering patterns, harvests and other agricultural activities, while causing losses of productivity and increasing expenses and the cost of labor in the field.”
In late 2012 and early 2013, the coffee growers of Central America faced one of the most serious crises to date — a leaf rust attack. Called roya in Spanish, this disease, produced by the fungus Hemileia vastatrix, has affected 49% of the region’s coffee farms, according to data from Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), and has caused a loss of USD 700 million in coffee for export. Thousands of coffee farmers have lost part or all of their plantations.
Among the reasons given by experts to explain this crisis, global warming stands out. Central America, like other tropical regions, is facing rising temperatures and extreme weather events that generate more heat and humidity, two conditions that create the ideal habitat for the leaf rust and other pests and diseases to flourish. We talked with Mario López, senior associate for Sustainable Agriculture projects at the Rainforest Alliance, who tells us more about the challenges that climate change is creating for the farmers of Latin America.
Question: How can climate change affect farmers?
López: Producers are telling us that they feel more heat and the rains are changing; they used to be able to count on the rainy season starting in May and finishing in late October or early November in Central America. The rains that once fell over six months are now concentrated in only three — August, September, and October. This affects the soil moisture that is essential for the development of strong plants and changes their growth and flowering patterns. It also requires making changes in the entire crop management process, which can affect yields and generally have a negative impact on the crop. Furthermore, the increased heat and humidity in certain places and months favors the development of pests and diseases, which migrate to places that did not have them before.
Q: Was this the case with the leaf rust attack?
López: The leaf rust epidemic is a very clear example. The fungus that causes leaf rust prefers warm habitats with high humidity, conditions that occurred in the 2012-2013 season, which facilitated the fungus’ spread throughout Central America. Other factors that worsened the crisis were that producers were unprepared for such a strong attack and the fungus even spread to coffee farms at higher elevations of 3,900 to 4,900 feet (1,200-1,500 meters). This kind of epidemic could also happen with various insects, other fungi, bacteria and other organisms that thrive in warmer climates and are harmful to agriculture.
Q: Why do unstable rainfall patterns harm or even destroy crops?
López: First, because rain is essential for the life cycle of a plant. Plants need water to germinate. If a farmer plants his vegetables in May when it is assumed the rains will start, but there is no rain, the plants won’t germinate. Or maybe it rains for a few weeks and then stops raining, and the plant cannot finish developing. Other types of crops that are not planted every year, such as coffee, need a certain amount of soil moisture so that the plant can carry out photosynthesis and therefore have good flowering followed by fruiting. If it does not rain on time, the flowering pattern will change; if it rains but then the rain stops, it will flower, but the fruit does not develop well and that harvest is lost. And if the rains start early, the crop changes its physiological functions and this ultimately affects production. Extreme rainfall events are more frequent now, and after two or three days of storms, entire plantations can be wiped out from floods or mudslides.
Second, most farmers in Latin America depend completely on rainfall to grow their crop; only a few, mostly large farmers, have irrigation systems to help manage the instability and shortage of rainfall, or greenhouses or other infrastructure to protect against excessive rain or heat.
Q: Are droughts also an important threat?
López: This is another serious problem. Some areas areexperiencing a longer and more intense rainy season, followed by droughts that cause soils to have very little moisture in the first 20-30 cm, which forces the plants to expend a lot of energy to make their roots penetrate even deeper in search of water and nutrients. This leads to a weakening of the plants, reducing their capacity to produce fruit. In addition, groundwater is being depleted by agricultural and urban overexploitation, reducing the availability of water to the plants. As a result, crops that have always relied on rainwater alone now require irrigation systems that are usually too expensive for small producers.
Q: Are there human-caused factors that are making farmers more vulnerable to climate change?
López: Yes. In addition to the unsustainable use of water resources, the overuse of chemical products over so many years has created resistance in many pests and diseases that are now finding optimal growing conditions, thanks to global warming. On many farms, the removal of all ground cover and plants other than the crop was promoted, which killed soil microflora and microfauna essential for enriching the soils, maintaining moisture, and even providing natural biological pests and disease control. For example, if leaf rust reaches a coffee plantation where the only vegetation consists of coffee plants, it will attack the coffee with full force. In our experience, on Rainforest Alliance CertifiedTM farms other plants or trees remain and are planted, and these harbor diverse insects and microorganisms.As a result, , the incidence of rust has been much lower.
Another mistake has been to remove shade trees from plantations, exposing coffee bushes to increased heat and leaving the soils more exposed to erosion and prone to landslides caused by heavy rains. But Rainforest Alliance certification requires a minimum amount of shade cover, which helps protect coffee plants.
Q: Which crops are most affected by climate change?
López: In Latin America, the Rainforest Alliance works mainly with coffee, cocoa, palm, pineapple, and banana, and all are being affected by climate change. Global warming and extreme weather events are disrupting the entire production schedule, pruning, flowering patterns, harvests, and other agricultural activities, while causing losses of productivity and increasing expenses and the cost of labor in the field. Crops like corn and beans are also affected, and these are key to the food security of many countries.
Q: Will farmers be able to adapt and continue farming in spite of the climate challenges?
López: If they receive the information, guidance, and technology they need, they will be able to adapt, but in different ways. For example, it is very probable that coffee and cocoa farms will have to migrate to higher elevations. The same could happen with some legumes, vegetables, and fruits – we will have to move these crops or grow them in greenhouses to be able to control growing conditions. Large plantations such as pineapple, banana, and oil palm cannot be moved because of the topography of the soils – these crops are planted on very large plains, hence the entire productive systems would have to be changed. And those small producers who cannot relocate and do not have the money for technologies and infrastructure will probably continue farming their lands but with different crops.
Q: How does the Rainforest Alliance help farmers adapt and mitigate climate change?
López: Rainforest Alliance CertifiedTM producers use sustainable, climate-friendly agricultural practices that, for example, favor agroforestry systems with shade trees, live plant cover, and natural barriers, which ensure cooler microclimates and less heat stress while also capturing carbon. They also help keep soil moist, rich, and resistant, and reduce vulnerability to pests and diseases. Certified farms implement integrated management practices and are constantly monitored, ensuring a faster response to threats from climate and disease. In 2011, the Climate Module of the Sustainable Agriculture Network was launched, which added 15 climate-related criteria that have proven to help mitigate climate change and increase the resilience of farms. About 350 producers in Latin America are verified for compliance with the Climate Module. Additionally, we are providing training and specific tools for climate change adaptation and mitigation, which are used to analyze risks on farms and help control the main threats related to climate change.