Climate change has directly and severely threatened the production and self-sufficiency of rice, which is the biggest and most important food grain in China and vital for the country's food security. China is the world's largest rice-growing nation, producing more than 200 million tons of rice per year that accounts for over one-third of total grain production of the country. In 2014, the share of rice production in China's GDP was 1.02% which is over two times as the global average level (GTAP Database, 2019). Rice accounts for 6.25% of household food expenditure in 2014 (GTAP Database, 2019), and its per capita consumption has increased from 42.5 kg in1961 to 77.45 kg in 2013, which is 1.4 times the global average level. Since the early 2010s, due to a slowdown in the growth of rice production and rapid increase in rice consumption, China has changed from a net exporter of rice to a net importer.  

In recent decades, China has sustained a high level of rice self-sufficiency (above 97%) due to the low level of rice import (less than 3 million tons per year) in the past decades. However, like other crops, rice production in China is vulnerable to climate change that affects radiation, rainfall, and temperature: the essential elements for effective photosynthesis. An increasing number of studies confirmed that climate change has significant negative impacts on China's rice production, consequently threatening its rice self-sufficiency. Therefore, the impacts of climate change on China's rice self-sufficiency should be carefully evaluated.

Numerous studies have evaluated the impacts of climate change on the paddy rice yield; however, there is a large statistical dispersion in the changes in China's paddy rice yield due to differences in the study area, crop type, scenarios, and whether CO2 fertilization effect is considered. Without considering CO2-fertilization effects, China's paddy rice yield decreases by 6.1–18.6%, 13.5–31.9%, and 23.6–40.2% under global temperature increases of 1 °C, 2 °C, and 3 °C, respectively also found that climate change would reduce paddy rice yield by 2–16% by the end of this century. In the South China that accounts for over 80% of national paddy rice production, temperature rise would have statistically significant and negative effects on paddy rice yield. These studies have evaluated the impacts on paddy rice yield using climate results from IPCC Special Report on Emissions Scenarios (SRES), and found that paddy rice yield would decrease by 1–10%. Meanwhile, paddy rice yield would decline by 3.3–10.3% in China's northern province of Heilongjiang, and the paddy rice production would largely decrease by 8.1–8.5%, based on historical climate change data. also found that paddy rice yield in Northeast China would decline by up to 15% in the 2080s under SRES A2 and B2 scenarios.

A consensus among the existing studies is that climate change would threaten China's rice production and self-sufficiency. Several agronomists have used crop simulation models such as the CERES-Rice and found that climate change has negative effects on China's rice production. Based on historical data and the econometric model, found that climate change had a negative effect of up to 5.35% on China's rice production in the main rice-producing areas during the period from 1979 to 2011. Using the multi-regional computable general equilibrium model (CGE),suggested that without considering the CO2 fertilization, climate change could reduce China's rice production by 5–7%, increase rice price by 2–7%, and reduce rice export by 10–20% towards the 2030s. According to, paddy rice yield in China is projected to decline by 1.34% and 2.60% by 2050 under RCP 2.6 and RCP 8.5 scenarios respectively, which would cause rice production to decline by 0.55% under RCP 2.6 and 0.22% under RCP 8.5, and the self-sufficiency rate to decline by 0.29% under RCP 2.6, and increase by 0.23% under RCP 8.5. Although climate change seems to pose serious challenges to rice self-sufficiency in the future, to our knowledge, the previous studies have not examined the changes in rice yield, production, and self-sufficiency with 2 °C rise in global temperature.

A series of economic equilibrium models have been widely applied in assessing the impacts of climate change on food self-sufficiency. Several studies have evaluated this issue by using single-country CGE models. Single-country CGE models can show the impact mechanisms of climate change through the domestic market, but they may either overestimate or underestimate climate change impacts by ignoring the feedback mechanisms originating from the global market. For this reason, an increasing number of studies have used multi-country CGE models to evaluate the impacts of climate change on food self-sufficiency . For example, have analyzed climate change impacts on China's agricultural production and found the mitigation capacity of the domestic market and global trade to climate change damages. show that international trade plays an important role in facilitating global food security in the face of a changing climate. However, they have not explicitly analyzed the role of different regional feedback mechanisms through the global market in assessing climate change impacts.

Two ‘families’ of climate change scenarios have been widely adopted in previous literature, including the SRES and Representative Concentration Pathways (RCPs). In 2009, an agreement was reached at the Copenhagen Conference that all parties should take urgent action to reduce greenhouse gas emissions in order to limit global warming to 2 °C above pre-industrial temperatures by the end of the 21st century. Compared with other climate change scenarios, a rise of 2 °C in global temperature is most likely to become a reality as it fully considers the trend of global temperature rise and various mitigation measures put in place. IPCC latest special report has emphasized that climate-related risks to food security are projected to increase with 1.5 °C rise in global temperature and increase further with 2 °C.

The purpose of this paper is to explore the impacts of climate change on China's rice self-sufficiency, with a focus on the scenario of a 2° global temperature rise, and to investigate the impact and transmission mechanisms of climate change through market and trade. To achieve this goal, we estimate the impacts of climate change on paddy rice yield in each country based on the estimated results from IPCC, then simulate the impacts of climate change on China's rice self-sufficiency with GTAP - a multi-regional, multi-sectoral general equilibrium model. This study contributes to the existing literature from the following perspectives: 1) This paper empirically analyzes the effects of active and passive regional feedback mechanisms of climate change impact on agriculture through global trade, which are ignored by most of the current studies. 2) A simulation method is developed that switches different regional feedback mechanisms with the same CGE model by changing alternative scenarios and closures. 3) A decomposition formula for rice self-sufficiency is employed to identify the major factors affecting China's rice self-sufficiency, and the latest version of the GTAP database (Version 10) is used. This study is also important for a better understanding of China's rice self-sufficiency under climate change, and the research and policy implications for climate change policy in the future.

In the next section, we introduce the changes in paddy rice yield of countries in response to global temperature rise and Section  3 describes the simulation model and methodology. The simulated results of the impacts of climate change on rice self-sufficiency are discussed in Section 4. The final section concludes this study with research and policy implications.

该文章以“Impacts of climate change on self-sufficiency of rice in China: A CGE-model-based evidence with alternative regional feedback mechanisms”为题，发表在《Journal of Cleaner Production》Volume 230, 1 September 2019, Pages 150-161