Researchers estimate that between 44 and 57 percent of all greenhouse gas emissions (GHGs) come from the global food system. Agriculture and deforestation caused by agriculture account for 26-33 percent of total emissions, making it a major contributor of climate change.
Chemical fertilizers are the main source of climate-changing gases. No country uses more of them than China, which now accounts for a third of global fertilizer use. These are mostly nitrogen fertilizers, which are produced from coal. The average Chinese farmer applies over 600 kilograms of chemical fertilizers per hectare—more than triple what the average farmer uses in Brazil and nearly five times that used in the U.S., where fertilizer use is also a growing problem.
Furthermore, only a third of the nitrogen fertilizer applied to China’s wheat and rice crops is absorbed by plants. The rest ends up in rivers or the atmosphere.
Fertilizers are responsible for numerous environmental and health calamities. Our research shows that, because of its destructive impacts on soil fertility, fertilizers are contributing to dwindling yields. Over the past 40 years, the efficiency of nitrogen fertilizers has decreased by two-thirds globally, and their distribution per hectare has increased by seven times.
Kicking the fertilizer habit will require more than a technological fix. For decades, global agricultural policies and research and extension program have focused on a “Green Revolution” model of farming (large-scale crop production), based on a narrow set of seed varieties that only produce high yields when doused with fertilizers and pesticides.
The Green Revolution was implemented throughout Asia, but the most emblematic cases would be India and the Philippines. In China, farmers can achieve similar yields without chemicals using agro ecological practices but they will need a lot of support in rebuilding their systems of farmer knowledge and of diverse seeds. They also need access to land.
Throughout Asia, the mass migration of peasants to urban centers has been driven by industrialization and policies favoring imported foods and agribusiness companies. Just 6 percent of Asia’s farm owners hold around two-thirds of its farmland.
In China alone, there are now over 120 million landless people, up from 40 million just 10 years ago, and the overall rural population has dropped from 80 percent to less than half today. Rural poverty has worsened despite galloping national economic growth, and the richer urban population has faced a spate of food scandals and new health issues, such as bird flu and obesity.
Some of the problems caused by China’s shifting food system are now being exported to countries like Brazil and Indonesia, where the expansion of plantations to provide China with soybeans and palm oil has caused deforestation, pesticide pollution, and violent land conflicts.
At home, agribusiness and meat corporations have boomed; small farms and local butchers have been decimated. Take the case of China’s most important meat: pork. Through the 1980s and 1990s, consumption of pork increased markedly, and that demand was supplied by small farmers raising backyard pigs. Environmental problems were limited because these pigs were largely fed with household waste and local crops, and farmers earned an important additional source of income that helped sustain rural communities.
But by the end of the 1990s, production shifted towards large factory farms that rely on imported feed crops and that generate tonnes of fecal waste and disease outbreaks, not to mention greater greenhouse gas emissions and rural exodus.
The situation is similar in other Asian countries and with other farmed animals. In the Philippines, for example, the entire supply of chicken and eggs came from small farms 40 years ago, but today 90 percent of the chicken meat in the country is imported or produced on large, factory farms.