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    Irrigation - The Big Carbon Elephant In The Global Warming Room
    By News Staff | March 17th 2012 01:00 PM | 3 comments | Print | E-mail | Track Comments
    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.

    How do they know?  You can't even count the people in China because by the time you finish counting, the number has changed a lot so counting water is just as hard.  They used survey data collected from 366 villages in 11 provinces and then up-scaled those results to calculate the emissions created by groundwater pumping across China's remaining 20 provinces.

    China is the largest greenhouse gas emitter in the world, with around 17 percent of emissions coming from agriculture. Irrigated agriculture in China produces 70 per cent of the country's grain and the pollution is caused by the huge amount of energy needed to pump water from underground – in some areas from an average depth of 70 meters. 

    The results account for more than 0.5 per cent of China's total CO2 emissions - which doesn't sound like much but in context that is the total amount of CO2 all of New Zealand emits in one year.


    Credit: Jinxia Wang, Centre for Chinese Agricultural Policy (CCAP)

    With a growing population, climate change and socio-economic transition, the report predicts the problem will worsen unless action is taken to improve China's water management policies.

    Prof Jinxia Wang of the Centre for Chinese Agricultural Policy said, "Improved access to pumping technology, cheap energy and the ability to directly control water availability has led to a massive expansion of groundwater pumping across large parts of Asia, particularly in China and India. The small scale of pump operations makes regulation and control of use extremely difficult."

    Published in Environmental Research Letters.

    Comments

    blue-green

    Sheesh …. is no one going to calculate the Oxygen created from this irrigated land? Meanwhile, those water pumps will soon be switched to photovoltaic sources (if not already). Been there, doing that. 70 meters for a submersible pump will soon be average. No big deal. Get used to it.


    What sort of nonsense is this? The East Asians eat rice and the south Asians eat wheat. They do this to stay alive. They have as much right to eat and stay alive as the rest of us! The Chinese population is largely stable thanks to their population policy and as the Indians become more affluent their birth-rate decreases. These are largely populations of intelligent people doing what is in their interest and their National interest. Beside their efforts, the article above is nothing more than rampant nonsense. The author has obviously very little to contribute to humanity's struggle unlike the Indians and Chinese! This article is on the level of those bewailing farting cows. I prefer farting cows to this sort of rubbish.

    Thank you for the article and reflects the difficult sitution we find ourselves in. Not only is this pumping causing pollution and greenhouse gas emissions, it is "mining" or lowering the water table. This is being done worldwide (even here in the United States ) and is not sustainable.
    I would like to point out that even with the population controls implaced in China the numbers keep growing. It is because of the dynamics of demographics.
    The sad fact as these societies grow "richer", they adopt a more meat based diet and that in turn places more demands on the water resources. It will be interesting, as they say in China, to see how all this "pans" out.