Peak Food and Population Overshoot

by John Rawlins / from whatcomwatch.org

Before oil (and natural gas) humans used manual labor to grow food, and the amount of food determines an upper limit on population. The large-scale, increasing use of oil and natural gas in the industrial world’s food-growing enterprise has meant ever-increasing quantities of food — until now. Therefore, population increase over the past 150 years correlates very well with oil extraction.

By far the largest population increase in the history of humans occurred in the 20th century, and the resources making that possible were oil and natural gas. Now that we face a very near-term decline in both of these resources, it is time to start planning how we will continue to feed a population of over 6 billion humans. In about 100 years, when oil and gas are essentially gone, will it even be possible to provide enough food for six to 10 times as many people as populated the planet before oil and gas?

... From a few million years B.C. to around 10,000 B.C. world population was likely in the few million range, and the technologies that were important in that period included use of fire, tool-making, spears, and bow-and-arrow. During this period, humans were in hunter-gatherer-scavenger groups. They ate mostly what nature provided: fruits, nuts, berries and meat from other mammals. During this, the longest time period on the list, remember that a few million humans were matched with the available natural food supply.

The next great innovations were cultivation of plants for food and bronze metallurgy. Human diets changed dramatically during the next 6,000 years as a result, and people didn’t have to travel as far to find food since they had planted some of it. The use of grains began during this important period of human history, and population expanded to nearly 100 million humans.

From about 4000 B.C. until around A.D. 1800, humans invented the plow, iron tools and small firearms. Even with those innovations, the population only increased about 10-fold to around a billion people. Even though large population centers developed and persisted, most humans were in some way involved in food production. This 10-fold population increase took only about 6,000 years, comparable with the rate of population growth during the preceding period — a rate of increase of around 1 percent per generation.

Around 1800 the industrial revolution began with the use of fossil-fueled machinery — the beginning of the age of coal. Since it was tough to use coal to grow more food, the population by 1865 was still only about 1.4 billion people — but that represents a 14 percent per generation rate of increase.

With the discovery of the most convenient energy resource humans will ever know — oil — fossil fuels could power farm machinery and greatly expand world food production. In parallel, medical advances extended life expectancy and reduced risks of childbirth, and the rate of population increase blossomed to nearly 30 percent per generation.

...Even if we are currently near the present limit of planet Earth’s human capacity, remember one important fact — the dependence of our food supply on those very fossil fuels that will soon be available in declining amounts: oil and natural gas. So what are the numbers showing this oil/gas dependence in our farm sector?

Today, about 75 percent of direct farm energy use in the U.S. is from diesel (largest), gasoline, LPG (liquid petroleum gas) or natural gas. The remainder is electricity — which in the U.S. is on average mostly generated by fossil fuel — coal and natural gas primarily. The bottom line: the energy responsible for our nation’s food production is about 80 percent oil and natural gas or its derivatives. That just covers food production — but what about the rest of the food chain? Food production accounts for just 21 percent of the energy use in the entire food system.

The average distance that food travels in the U.S. from farm to platter is 1,500 miles. Transporting that food consumes 14 percent of the food system energy, and it’s almost all diesel fuel — an oil derivative. Processing, packaging, food retail, restaurants and home refrigeration and preparation make up the remaining 65 percent — and most of that energy is from electricity with its fossil fuel dependence. Clearly, we have built our food system on energy derived almost entirely from non-renewable sources...

An interesting result of the U.S. food production business is that only about 1 percent of U.S. residents work at farm-related jobs — down from around 50 percent in the pre-industrial age. So we live in a country in which very few have food-growing knowledge, and much of that is not even applicable to the post-carbon era that is rapidly approaching. Likewise, the knowledge required for food preservation is greatly diminished from pre-industrial times.

Since current industrialized nation food production is completely unsustainable, and is already experiencing oil/gas cost increases as peak oil/gas production approaches, it is time to begin planning for a very different world — one in which conventionally produced food will cost more, one in which total food supply will decrease, and one in which many more people must learn to produce and preserve food without the prodigious oil/gas requirements. Finally, we cannot learn from our present food production practices the answer to the original question posed: How many people can planet Earth support in year 2100?

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