Global commodity price inflation and food prices

A commodity price index is a tipical indicator used to calculate changes in inflation. It is a weighted average of selected commodity prices. These commodities are usually taken from different categories of goods, such as energy, metals and agricultural goods. Here is a tipical commodity chart:

By looking at it it is clear that  prices of goods have increased dramatically in the last 20 years.













Now let's focus just on food prices. It shows that most agricultural goods have increased in price since by almost 60 % from 2006 to 2008. (Trostle, R. 2008). http://www.ers.usda.gov/Publications/WRS0801/WRS0801.pdf
We can deduce that agricultural commodities were among those goods that pushed prices up.

So what is the reason for the dramatic food price increase starting in 2006 up to 2011? The law of supply&demand would have us believe that people were buying much more than they were selling, but was this really the case?

Reasearch from the U.S. department of agriculture shows that there were many possible causes that could have led to food price inflation. Population and economic growth, rising per capita meat consumption (which in turn pushes up the price of wheat or other agricultural commodities used to feed animals), slowing growth in agricultural production, rapid expansion in biofuels production, dollar devaluation and rising production costs are among the most commonly accepted factors driving up prices.

The problem with this is that it fuells speculation-as investors expect prices to rise in the future, they buy commodity futures and this pushes prices up even more. So the result is that that speculators worsen a situation that is already dangerous. Just think about the consequence that such a food price inflation has on people living in thirld world and developing countries.