DUJIADUN, China -- Liu Changxiong has been farming in this southwestern Chinese village for more than a decade, but his years of experience aren't of much use these days.
Last year, his corn seedlings withered at a time Liu expected would be rich in rain. It took twice as many days for his green onions to grow than Liu's estimates. But the 43-year-old farmer isn't the one to be blamed. Instead, experts say, his farming routine is being messed up by climate change.
Similar phenomena are happening across the nation. In north China, where wheat fields have dominated the landscape for centuries, the crop is becoming increasingly difficult to grow as the land gets drier and warmer. In southern China, droughts in recent years have replaced rainy seasons, drying up rice paddies on a large scale.
Experts are scrambling to understand the problems and to predict how serious they might become. Although forecasts for crop output vary, most agree that the future climate won't be as favorable to agriculture. While China's hunt for adaptation measures is on, little progress has been made so far.
That raises the question of whether 1.34 billion Chinese -- accounting for almost one-fifth of the world's population -- would be able to feed themselves. Currently, China produces slightly less grains than its people consume. Crop losses caused by extreme weather events, insect attacks and other problems associated with climate change are rocking the already delicate balance.
In 2011 alone, droughts claimed grains that could have been sufficient for nearly 60 million Chinese to eat for a whole year, official statistics show.
There is also the issue of rising crop production costs being driven higher by climate change. For one, as temperatures rise, many insects that used to be killed off by the cool of winter now live longer, forcing farmers to spray more pesticides. That increases food prices, and adds pressure on the lives of the poor.
Genetic engineering becomes less helpful
Worse yet, China is losing its ability to produce more. During the past decades, farmers here have enjoyed an explosion of productivity, thanks partly to genetically manipulated crops that are higher-yielding and resistant to pests and diseases. But today, that help is starting to fade away, as it is falling victim to climate change.
"In the 1970s, when we used genetic engineering technology to breed regionally adopted crops, we could enjoy its high yield for years; now that period is much shorter," said Pan Genxing, director of Agriculture and Climate Change Center at Nanjing Agriculture University.
What is defeating the technology, according to Pan, is that the environment in which the crops grow keeps changing due to climate change, making regionally adopted crops no longer a fit for the region they were designed to.
To be sure, not all the effects of climate change are an agricultural curse. For instance, the higher temperatures allow crops to grow in areas which were previously too cold, and lengthen the growing season and, for some crops, the number of times per year they can be harvested. But whether China can take advantage of those changes is another troubling question.
Along north China's Haihe River Basin, where crops can now grow twice a year thanks to warmer climate, local farmers still plant only once, for lack of water, says Mo Xingguo. He researches climate change and agricultural water use at the Chinese Academy of Sciences.
Experts say that other parts of northern China, which were to enjoy greater numbers of harvests per year as the climate gets warmer, confront the same obstacle. Irrigation there largely relies on groundwater, and to grow more crops would require pumping more water out of wells, an unlikely prospect in a land whose groundwater level in recent years has already dropped dangerously.