… is from page 400 of Indur Goklany’s superb 2007 book, The Improving State of the World  (footnote excluded; original emphasis):
Trade also reduces the pressure to exploit marginal land resources, which helps avoid additional, and unnecessary, environmental degradation. If in 1997 there had been no trade in cereals and if each country increased (or reduced) cereal production by an amount equal to its net imports (or exports), then at least an additional 26 million hectares (Mha) more would have had to be harvested worldwide.
DBx: By encouraging production in ways that use resources most efficiently, trade not only makes the world more prosperous – from each given physical quantity of resources we get more output – trade is also better for the natural environment than are trade restrictions and other “buy-local” efforts. The many “Progressives” who take pride in their love and respect for the natural environment, yet who also support protectionism and “buy-local” movements, do not understand that, short of humankind committing mass suicide, protecting the environment necessarily entails using resources as efficiently as possible – and that free trade, domestically and internationally, is indispensable if we wish to get as close as possible to fully achieving this goal.