Just in time for next Sunday's Earth Day observance, a study published in last week's Environmental Research Letters warns that animal manure and fertilizers used in growing animal feed emit large amounts of nitrous oxide, a powerful greenhouse gas.

An op-ed piece this month in the New York Times warns that the devastating environmental impacts of a meat-based diet are actually magnified when raising animals on the range, because this involves much more land and more greenhouse gas emissions.

These conclusions are in keeping with an extensive United Nations Environment Program's report, which drew on dozens of smaller studies.

The report concluded that agricultural production accounts for 70% of global freshwater use, 38% of land use and 19% of greenhouse gas emissions.

In an environmentally sustainable world, meat and dairy products must be replaced by vegetables, fruits, and grains, just as fossil fuels must be replaced by wind, solar and other pollution-free energy sources.

As the world's most conspicuous consumers, we have a special obligation to lead in pursuing an environmentally sustainable lifestyle. Our next trip to the supermarket is a great starting point.

Branden Kusher

Burbank