Why are the world's farmers now struggling to keep pace with population growth, when they used to have the lead by a comfortable margin? This change is particularly striking, because population growth is now lower than it was in the 1960's and 1970's when per capita and total grain production were both increasing.

Many resources are becoming increasingly limited , including

(1) OIL -- (fossil fuels in general). Increases in prices were important in contributing to slowing rate of increase in food production. (Click "Oil" to examine this connection now, if you wish.) In a nutshell, "We have a food system designed for oil at $15 a barrel." (Paul Roberts, writing in, "The End of Food."

(2) TOPSOIL – We will focus on this in a later lecture (click "Land" to take a brief look at this now, or "Land degradation" for a more detailed examination), but for now, it is sufficient to realize that we are losing land and soil it at a tremendous rate. Globally about 25 billion tons of topsoil per year are lost to erosion.

(3) GENETIC RESOURCES – We are facing a diminished diversity of crops and varieties within crops, which affects production both over the short term and over the long term. (Click "Diversity" to jump ahead to this discussion, if you wish).

(4) WATER -- In many areas, groundwater is being withdrawn faster than it is being recharged, and surface waters also are in limited supply. Supplies of both are affected by competition from non-farm uses, such as needs of urban areas. (Click "water" if you want to jump ahead to a discussion of this.)

(5) LAND -- We've already seen recent trends in acreage devoted to grain (click "trends" to review that information); land suitable for agriculture is in limited supply (click "land limitations" to move to a discussion of those limitations now, if you wish.)

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