Rice Feeds Billions But it Fuels Climate Concern

May 26, 2026

There is no denying the fact that rice feeds more than half of the population across the planet. From terraced paddies in Southeast Asia to irrigated fields in China and India, it underpins daily meals for billions of people.

But the same flooded soils that help rice thrive also create ideal conditions for microbes that release climatewarming gases. According to a latest survey, greenhouse gas emissions from rice paddies have nearly doubled globally since the 1960s, averaging about 1.1 billion tons of carbon dioxide-equivalent emissions per year in the 2010s.

This makes ricegrowing the largest emissions source in agriculture outside of livestock, and rice demand is expected to go up further. Farmers have ways to reduce their rice crops’ emissions without lowering their yields.

If every grower used the best currently available “climate-smart” options, we found that global rice emissions could be reduced by about 10% by mid century. However, greater reductions are needed to slow climate change, which would require developing additional, more effective strategies.

Rice emissions have risen for two reasons: the expansion of rice cultivation area and the intensification of management practices. Just over half of the global increase is from the expansion of rice-growing areas. In Africa, for example, the ricegrowing area has roughly doubled since the 1960s, helping drive a twofold rise in methane emissions in the region. At the same time, rice farmers are using more fertilizers and organic amendments, such as straw and manure, planting more productive rice varieties and growing the plants closer together.

The result is more rice but also more greenhouse gas emissions. One practice in particular – leaving rice stalks in the field after harvest and then plowing them into the soil to improve soil fertility – was responsible for about 18 per cent of rice’s increase in overall net emissions since the 1960s.

The reason: It increases the organic matter in the soil, which microbes then decompose, creating more methane emissions. Rising global temperatures further accelerate microbial activity in the soils, meaning even more emissions. Fertilizer is another major contributor to emissions. Use of synthetic nitrogen increased by about 76 per cent after 2000, boosting nitrous oxide – another powerful greenhouse gas. It contributed about 9 per cent of the increase in total global net emissions from human activities. Irrigation practices also affect emissions.

In the past, irrigated rice paddies were kept flooded throughout the growing season, resulting in constant greenhouse gas emissions produced by microbes that thrive in the wet environment. Over the past two decades, however, more farmers have used intermittent flooding – draining their fields periodically.

This change has lowered methane emissions compared with keeping the paddies continuously flooded. However, we found a slight increase in nitrogen oxide emissions as soils cycled between wet and dry, which induces microbes to transform nitrogen in organic matter into nitrogen oxide gases, particularly nitrous oxide. Putting a full climate price tag on rice production is harder than measuring one greenhouse gas at a time. Rice paddies emit methane and nitrous oxide from wet or flooded soils.

They also remove carbon dioxide from the atmosphere as rice grows, and they lose carbon from their soils between crop seasons. A credible global estimate requires consistently accounting for different gases and soil carbon changes, as well as the uncertainty involved in tracking data across space and time.

There are ways to reduce emissions from rice production without sacrificing yield. Reducing fertilizer use and residue applications, managing irrigation to allow dry periods in between flooded ones and reducing tillage could, together, reduce global greenhouse gas emissions from rice by about 10 per cent by midcentury. Maintaining moderate amounts of straw and other crop residue in the field can help boost soil fertility, but too much can increase methane emissions and accelerate the loss of carbon from the soil.

Another option is to convert part of the residue into biochar – burning it under lowoxygen conditions before mixing it into flooded soils. Biochar can help stabilize soil carbon and reduce methane emissions. Improving water management can be a powerful tool for reducing emissions.

Periodically draining fields reduces methane production, though it may slightly raise nitrous oxide emissions. This strategy is particularly effective in regions with reliable irrigation infrastructure, including large parts of Asia. Managing fertilizer use is also an effective mitigation strategy, particularly in highly fertilized systems, including parts of China and South Asia. Excess nitrogen increases nitrous oxide without a clear increase in crop yields and increases water pollution. Reducing overapplication of nitrogen reduces emissions and water pollution, and it saves farmers money in the process.

The effects of tilling, the practice of plowing the soil between crop seasons, have large regional differences. Reducing tilling is often promoted as climate-friendly, but we found that it does not always minimize net emissions in flooded systems. In rice fields in temperate zones, including much of the U.S. and China, cooler conditions can limit methane production, allowing the soil carbon benefits of reduced tilling to outweigh the methane risk.

In warmer, persistently flooded systems, however, low-oxygen conditions can boost microbial activity, increasing methane production and accelerating soil carbon loss. The bottom line is both hopeful and sobering: Targeted sets of optimized practices can deliver meaningful emission reductions without losing rice yields, but the total global possible reduction is modest. To reduce emissions further will require better guidance to help farmers determine the best levels of organic amendments, such as straw or biochar, and new approaches that can reduce emissions without undermining rice production.