INSAM - International Society for Agricultural Meteorology
In a publication of late last year, from the Climate Change And Food Security (CCAFS) group (http://cgspace.cgiar.org/bitstream/handle/10568/21226/ccafs-wp-23-cc_impacts_CGIAR.pdf) there are predictions on how certain crops may be expected to behave under conditions of a changing climate. We used from this publication the section on rice. A month earlier the University of California, Davis, published in the journal “Nature Climate Change” a paper “Rice agriculture accelerates greenhouse gas emissions” (http://www.news.ucdavis.edu/search/news_detail.lasso?id=10382). Working in an extension project with rice farmers on the western north cost of the island of Java, Indonesia, we already used the publication “Climate Change and Rice Production”, No. 19 in the series “Questions and Answers” of the Philippine Rice Research Institute (www.pinoyrkb.com/main/ppt/doc_download/647).
Combining mainly advisories in these three publications with our experience published in some papers in the “agrometeorological extension” and “ethnographic anthropological” literature in the last few years, we (Kees Stigter and Yunita T. Winarto) wrote a paper “Rice and Climate Change” for a book to be published in Indonesia next year. We also produced a PowerPoint presentation of this material that we will present in various places in Indonesia from October 2013 onwards. After a general introduction on rice production, this material talks about its “Biological vulnerability to climate change” (temperature, carbon dioxide, floods, salt, drought and some minor other abiotic stresses). It suggests the need to develop crop plants with high levels of tolerance for combinations of stresses. The paper/presentation then continues with a paragraph on socioeconomic vulnerability of rice to climate change, and finally makes some critical additions not found or insufficiently dealt with in the three major papers reviewed.
Such issues related to climate change that are not or only partially dealt with in these papers used are (i) increasing climate variability/disasters; (ii) changes in pests and diseases vulnerabilities; (iii) changes in rice systems and diversification in cropping. Under this heading we underline a conclusion, drawn by many over the last decades, that depending on rice alone remains an unwise policy for Indonesia. This same argument we need to use in a discussion on whether and how Indonesian rice farmers need/will be able to adapt their rice farming to the causes and consequences of climate change. This brings to the above sequence a point (iv): diminishing contributions of rice to GHGs. We will add here our own experience in Indonesia as well. As to this point (iv), we suddenly are in mitigation issues.
When CH4 (methane) is released into the atmosphere, it traps significant amounts of heat that would otherwise escape to space. Methane is more than 20 times more heat absorptive than CO2 and it has a 9 to 15 years life time in the atmosphere. Thus, CH4 is considered a greenhouse gas that heavily contributes to global warming and climate change, owing to its greenhouse effect. Flooded rice fields emit significant amounts of methane to the atmosphere. As in all natural wetlands, flooding a rice field cuts off the oxygen supply from the atmosphere to the soil, which results in anaerobic fermentation of soil organic matter. Methane is a major end product of anaerobic fermentation. It is released from submerged soils to the atmosphere by diffusion and release of gas bubbles, and through roots and stems of rice. Because global demand for rice will increase further with a growing world population, results suggest that without additional measures, the total methane emissions from rice agriculture will strongly increase. Moreover, as more carbon dioxide enters the atmosphere, rice plants grow faster, experimental data showed. This growth, in turn, pumps up the metabolism of methane-producing microscopic organisms that live in the soil beneath rice paddies. The end result: more methane.
When the fields remain flooded for the entire growing season, there is more potential for CH4 emissions than when the fields are drained or permitted to dry at least once during the season. Methane production is negligible in upland rice because the fields are not flooded for any significant period of time. In rainfed fields, methane emissions are much lower and more variable due to periods of no standing water during the season. Too much use of chemical fertilizers and pesticides also emits N2O. Expansion of rice areas could also alter the earth’s land cover and eventually change its ability to absorb or reflect heat and light. This is all knowledge that we can use to design rice production that copes better with environmental issues and consequences of climate change.
These findings underscore the importance of mitigation and adaptation efforts to ensure a secure global food supply while keeping GHGs emissions in check. However, in principle, mitigation is for the real GHG polluters, not for the farmers in the South. In our earlier work of the past few years, on what climate change means for farmers in Asia and Africa, we have always taken the stand that only in win-win situations these farmers should be encouraged to apply mitigation measures. With this we mean that only when a proposed adaptation of their agricultural production to (the consequences of) climate change appeals to (in this case) rice farmers as helpful, useful and feasible, only then should they also assess the additional mitigation aspects of that adaptation.
Now in that paper of ours that we are discussing here, win-win situations for rice production are recognized in that (a) 5 of 8 proposed adaptations have possible mitigation components during an El-Niño period; (b) 1 of 8 proposed adaptations have possible mitigation components during a La-Niña period. We also found that for general win-win situations in rice (c) 7 out of 10 possible proposed adaptations had mitigation components, while (d) 4 out of 12 possible proposed mitigations had adaptation components. These results will now be used by us with our groups of farmers, to see which win-win situations, in their specific conditions, they consider suitable to be carried out. This is, in the end, long term participatory on-farm research, about which we will love to report to you in due course. However, when you would like to know about the adaptations and mitigations in (mostly) irrigated rice we talk about here, have a look at our paper at (http://www.agrometeorology.org/topics/climate-change/rice-and-climate-change-adaption-or-mitigation-facts-for-policy-designs).