Claims that local food production cut greenhouse gas emissions / by reducing the burning of transportation fuel / are usually not well founded.

Transport is the source of only 11 percent of greenhouse gas emissions / within the food sector, / so reducing the distance / that food travels after it leaves the farm / is far less important than reducing wasteful energy use on the farm.

Food coming from a distance / can actually be better for the climate, / depending on how it was grown.

For example, / field­-grown tomatoes shipped from Mexico in the winter months / will have a smaller carbon footprint / than local winter tomatoes grown in a greenhouse.

In the United Kingdom, / lamb meat that travels 11,000 miles from New Zealand / generates only one-­quarter the carbon emissions per pound / compared to British lamb / because farmers in the United Kingdom / raise their animals on feed (which must be produced using fossil fuels) / rather than on clover pastureland.

When food does travel, / what matters most / is not the distance traveled but the travel mode (surface versus air), / and most of all the load size.

Bulk loads of food / can travel halfway around the world / by ocean freight with a smaller carbon footprint, / per pound delivered, / than foods traveling just a short distance / but in much larger(→smaller) loads.

For example, 18­-wheelers carry much larger loads than pickup trucks so they can move food 100 times as far while burning only one­-third as much gas per pound of food delivered.