By Hadi, Prajogo Utomo; Istiqlal Amien

Introduction
This pilot study under CAPSA facilitation aims to investigate the El Nino phenomenon and its impacts on food production and availability in Indonesia. Based on the results of the study, policies to offset the impact of the El Nino phenomenon on agricultural production and to ensure food security are presented.

In Indonesia, rice has been the most important staple food in the people's diet; it plays a significant role in the national economy in terms of food supply, labour absorption, and national income. However, recent data show that rice production growth is still lower than the population growth, making Indonesia remain to stay in the Malthusian population trap. Food security will be threatened if factors that severely influence rice production, including unfavourable climate conditions, are not adequately addressed. Understanding the climate change and its impacts on rice production, therefore, is of crucial importance.

By definition, El Nino is an oscillation of the ocean-atmospheric system in the tropical Pacific that has important consequences for weather around the globe (Philander, 1990). In normal (non El Nino) conditions, the trade winds blow towards the west across the tropical Pacific. La Nina, on the other hand, is 'a cold event' or 'a cold episode', characterized by unusually cold ocean temperatures in the Equatorial Pacific. Impacts of La Nina tend to be opposite to those of El Nino. Indonesia is one of the regions in the world influenced by both El Nino and La Nina.

Agriculture's contribution to climate change
Agricultural systems produce sizable emissions of three primary greenhouse gasses (GHG): carbon dioxide (CO2), methane, and nitrous oxide. Specific activities related to growing, raising and harvesting food have large impacts on global warming. It includes enteric fermentation, manure, fertilizers, deforestation and soil disruption and fuel consumption (Anonymous, 1995), which are discussed briefly below

Enteric fermentation and manure: In the process of digesting plant matter (enteric fermentation), bacteria in the guts of ruminants produce and emit large amounts of methane gas. Livestock also produce manure which emits GHG as it decomposes. If the waste is allowed to degrade in the open air, aerobic bacteria will dominate the digestion and produce nitrous oxide in the process. In instances where the animal waste is pooled or submerged, as in feedlots or in rice paddies, the oxygen available to bacteria is limited. Here, anaerobic bacteria break down the material in a process that produces methane emissions.

Fertilizers: Many chemical/inorganic fertilizers that are used throughout modern global agriculture systems are manufactured from natural gas in a process that produces nitrous oxide. In Indonesia, nitrous fertilizers, especially urea, is produced and excessively used (Hadi et al., 2007 and 2009). The subsidized chemical fertilizers containing nitrogen to be allocated to farmers for 2010 in Java alone, are as follows: urea 3,486,000 tons, superphosphate (SP36) 614,500 tons, ammonium sulphate (ZA) 421,994 tons and compound fertilizers (NPK) 466,667 tons (Agriculture Ministry Rule No. 5/2009).

Deforestation and soil disruption: Throughout the world, forests (which act as carbon sinks by absorbing atmospheric CO2 in the process of producing biomass) are being cleared, and often burnt, in order to make room for crop land, tree plantation and pastures. In this process, much of the carbon content of these habitats, which may have accumulated over hundreds of years, is released into the atmosphere in a matter of hours or days. In Indonesia, slash and burn system of million hectares of natural forest is very common in Kalimantan and Sumatra, while in Java natural forests are relatively small and conserved.

Fuel burning and smoke emission: Tremendous amounts of fuel is burnt globally, emitting large amounts of Greenhouse Gas. In the process of transporting input materials and products both in agricultural and non-agricultural sectors also contribute to GHG emission. Smoke emited by large scale manufacturing plants have even larger share of carbon emission. In Indonesia, already large fuel comsumption is rapidly increasing, especially in Java with the highest transportation intensity.

Country's share to climate change
Few industrialized and emerging countries contribute to over 80 per cent of global GHG emissions. While many of them have ratified the Kyoto Protocol, some key players like China and India are exempted from the treaty obligations.

The US on the other hand has not ratified the Kyoto Protocol, but its government has promoted improved energy technology as a means to combat climate change, and various state and city governments have begun their own initiatives to indicate support and compliance with the Kyoto Protocol on a local basis.

 

 

Effects of climate variability and climate change on rice production

Effect of climate variability
Climate varies temporally either seasonally, intra-seasonally or inter-annually and in the long run. It is believed that climate change is driven by increasing atmospheric temperature. Intra-seasonal climate is a season break, which is wetter than the usual in dry season or drier during wet season during 10 days or several weeks. All these can disrupt water supply during the normal cropping rhythm commonly practiced by farmers that eventually cause lower yield or even crop failure.

Figure 2 indicates the inter-annual variability of harvested area in Indonesia during 1961-2008. Despite increasing trend of rice harvested areas since green revolution, it is significantly reduced by inter-annual climate anomaly. During the 48-year period, the harvested area of rice decreased 18 times with a rapid rate in some years of 1963, 1967, 1972, 1982, 1991, 1994, 1997 and 2000. This rapid decrease may relate to the El Nino phenomenon. Yet, the average annual growth rate of the harvested area during the stated period was 1.26 per cent/annum.

Effect of climate change
Higher temperatures generally shorten a plant's period of growth and increase potential for pest attacks and diseases, eventually reducing the yield. Change in rainfall pattern also alter cropping calendar and delay cropping time. The increased frequency and intensity of extreme climate events reduce crop production due to increased risk of flood and drought. Sea level rise is likely to inundate productive agricultural lands and increase soil salinity, potentially reducing crop productivity. Increased CO2 in the atmosphere is known to speed up growth through increased photosynthesis and the increased temperature raise respiration resulting in lower yield.

 

 

Simulation of the effects of different climate scenarios on rice yields was carried out for two sites in Java, namely Pusakanegara in West Java and Mojosari in East Java. Geographically, Pusakanegara is situated in northern coast, while Mojosari is in further inland of Brantas river flood plain. The climate profile of these two sites is indicated in Table 1.
 


 

Rice cultivars were IR42 in Pusakanegara and IR36 in Mojosari. The standard management practice was adopted, including transplanting rice seedlings 18 days after germination; two seedlings/hill at 20 by 20 cm spacing; two applications of urea, 58 kg N/ha before planting and 30 days after planting incorporated into the soil at a depth of 5 cm.

The simulation employed CERES (Crop Environment Resource Synthesis) model and three crop growth models of GISS (Goddard Institute for Space Studies), UKMO (United Kingdom Meteorological Office), and GFDL (Geophysical Fluid Dynamics Laboratory) with DSSAT (Decision Support System for Agrotechnology Transfer) software. The baseline climate data of 1976, 1982, 1987, 1991 and the corresponding years in the transient climate scenario (when El Nino events occurred) were utilized to simulate the rice performance for dry years in current and future climate conditions. The future of all climate variables were simulated based on doubling CO2 level from the pre-industrial time (prior to 1850) to 555 ppm.

The simulation results are presented in Figure 3. For the first crop in Pusakanegara, rice yield decreased during ENSO driven dry year, except for GISS climate scenario. For the second crop, the yield decreased more significantly, except for standard climate scenario that revealed higher yield. In Mojosari, by contrast, yield dropped significantly during ENSO driven dry year, both for the first and second crop of rice.

The change in rainfall pattern altered the timing of rice cropping such as late planting of the first crop (October-December) that pushes back the timing of the second crop (April-June). These late planting limits the possibility of the third crop when irrigation facility is not available or water supply in the irrigation network is limited.

A decrease in rice production on one side and an increase in rice demand on the other can exacerbate food shortage. Demand for food from the poor as their incomes rise will add to the national food requirements, while the rich are likely to increase their demand for food rich in protein such as meat and fish. When population pressure is increased, the poor are likely to be more concentrated in unfavourable regions.

The climate change will significantly reduce the food security situation, unless adequate adaptive measures are taken (IPCC, 2007). Climate change as projected using 21st century climate models will significantly alter food production that has direct implication to food security in the world (Rosenzweig and Hillel, 1998). Cline (2007) predicted that in 2080, the agricultural productivity in Indonesia will decrease by 15-25 per cent due to climate change, but considering the positive effects of increasing CO2 in the atmosphere, the figure would probably be 5-15 per cent.

Handoko et al. (2008) stated that increased air temperature can affect rice production in three different ways, namely (i) decreased harvested areas with decreased irrigation due to higher evapotranspiration, (ii) lower yield because of shorter time to maturity, and (iii) increased plant respiration. The estimated decrease in planted areas of rice by 2050 is 3.3 per cent in Java and 4.1 per cent in the outer islands from current level. The decrease in yield because of earlier maturity is estimated at 18.6 to 31.4 per cent in Java and 20.5 per cent in outer islands. Increased respiration due to increased temperature is estimated to reduce rice yield by 19.94 per cent in Central Java, 18.2 per cent in Yogyakarta, 10.5 per cent in West Java and 11.7 per cent outside Java and Bali.

 

Figure 3. Simulated rice yield as affected by climate change at Pusakanegara and Mojosari
(a) Pusakanegara

Recent study of Boer (2008) in Java also reported that increased temperature due to increased CO2 concentration will reduce crop yield. First, with zero agricultural lands conversion and constant cropping intensity of rice production at district level, rice production is predicted to decrease by 12,500 to 72,500 tons in 2025. Second, when annual land conversion rate of 0.77 per cent is considered with constant cropping intensity of rice production at district level, rice production is estimated to decline by 42,500 to 162,500 tons in 2025. Third, with zero agricultural land conversion and increased cropping intensity, the negative effect of increased temperature can be minimized. Increased rice cropping intensity can maintain rice production in most districts of Java in 2025, except in Tulung Agung and Kediri districts in East Java province; Purworedjo, Wonosobo, Magelang, Klaten and Sukohardjo districts in Central Java province; and district of Sleman in Yogyakarta province. However, when annual rice field conversion rate remains at 0.77 per cent, the increased cropping intensity will be ineffective to compensate the negative impact of the increased air temperature in 2025, particularly in Central Java. The measure seems to be effective only in some districts of the West Java and East Java provinces.

Conclusions and suggestions
Climate change is likely affect rice production in Java and elsewhere in the tropics, mainly due to rise in increased temperature that fasten crop maturity, extreme climate events that may lead to crop failure, and the possibility for significant rise in pest attacks and diseases. The situation is further exacerbated by rapid conversion of lands and competition for water from non-agriculture or higher-valued agricultural crops. Although rice consumption per capita is likely to become lower as income levels rise, increase in welfare and high population growth will increase demand for rice in Indonesia. Therefore, a strong policy framework, including measures for adaptation and mitigation, is necessary to ensure food security in the face of climate change.

Three specific areas that need particular emphasis are described below:

Anticipation Strategy should include: (1) Planning of infrastructure development such as irrigation, farm road as well as water distribution and management systems; (2) Improvement of human resource capability to understand climate change and its possible negative effects; (3) Development of information and early warning systems about flood and drought phenomena; and (4) Further research on plant breeding to produce drought- and/or salt-resistant crop varieties.

Adaptation Strategy: (1) The use of drought-resistant and/or salt-resistant crop varieties; (2) More efficient use of water resources; (3) Improvement of pest management; (4) Changes in planting time, cropping pattern and crop diversification: and (5) Reduction of chemical fertilizer use (especially urea) and more organic fertilizer application; (6) Improvement of livestock feeds and better management of their manure.

Mitigation Strategy: (1) Improvement of crop management, including management of soil nutrient, land use, soil organic matter and grazing land, as well as agro-forestry development and degraded land restoration; (2) Improvement of livestock systems that includes feed management, waste/manure management and animal breeding; (3) Carbon sequestration that involves zero soil tillage and conservation tillage; (4) Water pricing to force water users to be more efficient; (5) Reducing the burning of fossil fuels by, among others, substituting part of fossil fuels with biofuels; (6) Enforcement of land use policies, which discourage slash and burn expansion and extensive (rather than intensive) livestock rearing, as well as raising the opportunities for rural employment; and (7) Promotes communities to plant tree crops in any place wherever possible.