Rice and wheat take a lot of water to grow and no one eats more than China. That also means no one contributes more to global warming from irrigation than China - a whopping 30 million tons of CO2 per year just from the pumping systems China uses.
Like everywhere, water usage has gone up in China with the surge in population. Groundwater used for crop irrigation in China has grown from 10 billion cubic meters in 1950 to more than 100 billion today. The pumping systems which support this immense irrigation network annually produce 33.1 MtCO2e (33.1 mega tonnes of carbon dioxide equivalent), claims a new study.