Because our food production and distribution system depend on fossil energies.
Some people suggested we might turn to eating insects for our protein intake.
Even biologists from an Amsterdam University promoted this idea. Stupid!
Because insects are part the general food chain.
If insects would be "farmed" they would still need food and water. Where would that come from?
It's the same brainless idea that makes believe that genetic engineering could feed future generations. As if more outputs would not need more nutrient inputs.
After Peak-Oil, which we reached around 2005 and which may turn into a fossil energy downslope before 2020, we'll have to get by with less energy.
The consequences are conceivable, when we take into consideration that there is no equivalent replacement for fossil energies, neither in sufficient quantities nor in quality for the various uses of oil and gas as raw material for industry.
World Energy Outlook 2010