I read Lester R. Brown's book 'Plan B 3.0' about a year ago specifically interested in peak oil issues and global warning trends. He does a great job pulling together scientific research from a wide variety of sources to address many problems facing the world today and offering feasible solutions. The reading can be a bit overwhelming at times and can make one want to immediately jump to action. As I worked my way through a few chapters on food production, I felt a sudden urge to get outside and start digging up the backyard to plan space for a garden. The fact there is an inch or two of snow back there and that the ground is probably frozen solid was not going to get in my way.
In chapter Nine, titled 'Feeding Eight Billion People Well', Brown goes into some detail about maintaining the world's food supply and shares some ideas about how we can avoid depleting all of our natural resources in the process. He identifies water as being one of the most important resources we need to be able to manage.
Many countries have increased their grain production since the 1950s by making more land available, using genetically modified seeds, and an eleven fold increase in artificial fertilizer usage. Other techniques such as using multiple cropping which is where a farmer will plant different crops in the same field at different times of year. While larger crop yields are important, if we are to sustain larger world populations, we cannot maintain these levels of food production with current conventional techniques.
Currently, 70% of the the world's fresh water is used for irrigation. The fact that we are over using this water supply is starting to become evident as major rivers, like the Colorado River in the southwestern United States, have almost all of their water diverted before they reach their deltas. Almost 90% of the water that flows down the Colorado river is used for irrigation. The Colorado is also the major water source for drinking water for the southern states of New Mexico, Arizona and Southern California. There is also evidence that the Ogallala aquifer which supplies water for most of the middle states from South Dakota down to the northern parts of Texas is being depleted at a rate of 12 km3 (12 billion metric tons) a year. The Ogallala provides water for 27% of the irrigated land in the United States and provides 82% of the drinking water to the central part of the country. Some estimates only give this major water source another 25 years before it is completely depleted.
One obvious way to conserve water is to use more efficient irrigation systems. As much as 50% of the water used in flood and farrow irrigation systems is wasted. Overhead sprinkler systems use 30% less water and drip irrigation systems use up to 50% less water than traditional methods of irrigation.
Another way to conserve water is to grow crops that require less water. Many organic crops which do not use artificial fertilizers also have lower water requirements. The end products also have less water in them which many believe is why organically grown products have better flavor as they are not watered down as much as their conventional counterparts. It takes 1000 tons of water to produce 1 ton of grain, if more sustainable techniques were used for raising livestock, the amount of grain used for feed could be greatly reduced and the amount of water used would also be reduced.
Maybe a less obvious way which is available in countries like the US is to, as Brown puts it, 'move down the food chain'. The average American consumes roughly 800 kg of grain a year of which only 100kg is directly consumed as grain in bread, pasta and breakfast cereal. The rest is consumed indirectly through livestock and poultry products. Compare this with Italy which consumes 400kg of grain per person and India which consumes 200kg of grain per person. It's interesting to note that the Italians have a longer life expectancy than Americans partially due to the fact that wile the Italians do eat meat and cheese, their diets are more moderate than the heavy meat based diet enjoyed by many Americans. If Americans could cut 100kg of grain by removing some meat products from their diet, we could save 300 million tons of grain a year or 30 billion tons of water. This is enough to allow the Ogallala Aquifer and the Colorado River a chance to recharge again which will protect the drinking water for millions of Americans.
Brown then goes on to explain the impact the American diet has on climate change by suggesting that converting to a more Mediterranean diet would have the same impact on CO2 emissions as replacing an SUV with a Toyota Prius, not to mention the fact that a warmer climate means more water lost in irrigation due to evaporation. Overwhelmed again, I put down the book to go outside an inspect the future location of our new vegetable garden.