SRI & Climate Change
The Paris Agreement on Climate Change has now been signed by 194 nations. Those signatories have pledged to reduce green house gas emissions and to put in place policies and targets aimed at adaptation to and mitigation of climate change. They have also committed to making those policies gender-friendly.
The agricultural and food production sector is on the one hand, one of the biggest contributors to climate change and on the other, stands to become one of the most significant victims of any failure to act decisively to reverse current adverse trends in climate change and water availability. Small-scale farmers are the most vulnerable to such changes in water availability and a changing climate. Many areas of the developing world are already seeing large-scale de-peasantisation and the ‘feminisation’ of agriculture – both phenomena that are affected by climate change and the precariousness this brings to farming.
Increasingly, climate change is becoming a primary reason for policy-level support for SRI. Here’s why:
Irrigation for food production consumes about 70% of the world’s supply of renewable fresh water each year (1), with most being applied to irrigate rice. In more and more parts of the world, water scarcity is causing crop losses, crop failure, and conflict over diminishing resources. By implementing SRI practices farmers are mitigating the ongoing depletion of freshwater sources, and farmers in areas experiencing water scarcity are able to continue growing rice. SRI plants thrive with 30 – 50% less water exposure, compared to conventional production in which the rice is constantly flooded. Depending on the amount of water used conventionally, water savings of as much as 84% have been recorded (2).
Rice is the highest greenhouse gas-emitting food commodity.(4) The alternate wetting and drying practices (AWD) used in SRI represent a potential for the mitigation of greenhouse gas emissions. Studies outlined in Styger and Uphoff’s briefing paper on SRI as a Climate Smart Agricultural technique (4) show that methane emissions, which are 30 times more powerful than CO2 over a 100-year period, are reduced with SRI methods by between 22% and 64% because of the aerobic soil conditions. Some studies have shown that there can be an increase in nitrous oxide emissions under SRI conditions, although those are sometimes offset by a reduction in nitrogen-based fertiliser usage.(4) Thus, the overall Global Warming Potential of rice fields is reduced by between 20% and 30% with SRI.
Extreme Weather Events
While agriculture has always been vulnerable to extreme weather events such as storms, typhoons, flooding and drought, these phenomena are occurring more frequently and more intensely in many parts of the world. Drought in eastern Africa, floods in south Asia and storms, married with rising sea levels and saline incursion in southeast Asia are all impacting on local, regional and global food supplies. SRI can improve farmers’ resilience to such events. SRI plants have stronger root systems. The reduced competition between plants, together with the aerated and organic matter-enriched soils creates stronger plants above and below ground with larger, deeper root systems, which can better resist drought and extreme temperatures. SRI plants grow taller, have stronger and thicker tillers, thicker leaves, deeper roots, and a much larger root mass. Also, increases in beneficial microbial activity and processes have been recorded in the SRI plant-soil environment, which are key for improved plant performance and productivity.