Climate variability impacts on rice production in the Philippines.

Malte F Stuecker,Michael B Kantar,Michelle Tigchelaar,Vanesa Magar

doi:10.1371/journal.pone.0201426

Abstract

Changes in crop yield and production over time are driven by a combination of genetics, agronomics, and climate. Disentangling the role of these various influences helps us understand the capacity of agriculture to adapt to change. Here we explore the impact of climate variability on rice yield and production in the Philippines from 1987–2016 in both irrigated and rainfed production systems at various scales. Over this period, rice production is affected by variations in soil moisture, which are largely driven by the El Niño–Southern Oscillation (ENSO). We found that the climate impacts on rice production are strongly seasonally modulated and differ considerably by region. As expected, rainfed upland rice production systems are more sensitive to soil moisture variability than irrigated paddy rice. About 10% of the variance in rice production anomalies on the national level co-varies with soil moisture changes, which in turn are strongly negatively correlated with an index capturing ENSO variability. Our results show that while temperature variability is of limited importance in the Philippines today, future climate projections suggest that by the end of the century, temperatures might regularly exceed known limits to rice production if warming continues unabated. Therefore, skillful seasonal prediction will likely become increasingly crucial to provide the necessary information to guide agriculture management to mitigate the compounding impacts of soil moisture variability and temperature stress. Detailed case studies like this complement global yield studies and provide important local perspectives that can help in food policy decisions.

Highlights

Rice–which provides nearly half the calories for half the world’s population [1;2]–is a key crop for the Philippines: it is a staple food, the sixth highest per capita consumption in the world), as well as a major source of income
Irrigated rice production in the Philippines has almost tripled over the past thirty years, while rainfed rice production has seen a much smaller growth (Fig 1A). Yields for both production systems have increased steadily (S1A Fig). Besides this long-term trend, annual rice yields at the national level have been fairly stable over this period, with irrigated paddy rice production having only six yield anomalies exceeding one standard deviation, while rainfed upland rice crops exhibited eight yield anomalies exceeding one standard deviation
Relative anomalies in total rice production (Fig 1B) are larger than those in yield, implying that the effects of climate variability are compounded through both yield and harvested area changes

Summary

Introduction

Rice–which provides nearly half the calories for half the world’s population [1;2]–is a key crop for the Philippines: it is a staple food (with >110 kg/person/year consumption, [3], http://irri. org/rice-today/nourishing-a-nation), the sixth highest per capita consumption in the world), as well as a major source of income (rice production valued at ~6 billion U.S dollars in 2015; [4]). Rice–which provides nearly half the calories for half the world’s population [1;2]–is a key crop for the Philippines: it is a staple food Org/rice-today/nourishing-a-nation), the sixth highest per capita consumption in the world), as well as a major source of income (rice production valued at ~6 billion U.S dollars in 2015; [4]). The Philippines produces approximately 3% of the world’s rice in both “lowland” flooded transplanted paddies and “upland” rainfed direct seeded areas [5]. Surface air temperature (2m) was obtained from the ERA-Interim reanalysis on a 0.125o horizontal grid (https://www.ecmwf.int/). Future climate projection data were obtained from the CMIP5 database for the business-as-usual scenario RCP 8.5 (https://cmip.llnl.gov/cmip5/ data_portal.html)

Methods

Results

Discussion

Conclusion