When we think about things that threaten our environment, many of us probably think of cars, or maybe factories belching smoke.

When we think about things that threaten our environment, many of us probably think of cars, or maybe factories belching smoke.

But the truth is that agriculture emits more greenhouse gases than all the planes, trains, trucks and cars combined. This is largely from methane released by cattle, and by rice farms, plus nitrous oxide from fertilizers.

Add to this the factor of transporting the food hundreds or even thousands of miles, and we begin to see agriculture's impact. And we've not even factored in pollution from packaging, refrigeration, warehousing, pesticides, fertilizers and other chemicals.

By 2050, the world's population is expected to increase by 35 percent. To feed that population, crop production will need to double. Part of the reason is that as developing countries grow, they tend to eat more meat. Unfortunately, producing meat, dairy and eggs is not an efficient use of grain, with beef being the least efficient. For every 100 calories of grain fed to beef animals, only 3 calories come back to us as meat. Biofuels also use a lot of crop production that could be used as food.

So what's the answer to feeding more people while still protecting our planet? Must we all become vegetarians and give up our cars for bicycles?

Not likely.

But one thing seems to be clear — we need to use our resources more efficiently. One small step we can all take is to decrease the amount of food we buy that must be transported long distances.

Interest in farmers markets has grown nationwide at a tremendous rate in the last few years. In 2000, there were approximately 1,750 such markets. By 2013, there were nearly 8,200. In New York City alone, a place many of us wouldn't think of as having farmers markets, you will find more than 150 of them. In the rest of the country, the numbers have increased dramatically, too, with California topping the country with 759.

This interest has not arisen, I believe, because of a wish to save the planet, but because people want fresh produce, and they want to know where their food comes from, how it's grown, as well as wanting to invest in their local economies. Patronizing local growers markets fulfills those demands, and helps keep our environment healthy, too. If every Jackson County household spent just $10 per week on locally grown food, an additional $18.6 million would be pumped into the local economy every year.

Of course, growing your own food lets you know where it comes from and how it is raised. But perhaps you, like me, cannot raise all of the food you need. That's when it's time to shop for locally produced food. Shopping at our local growers markets in Ashland on Tuesdays and Saturdays and in Medford on Thursdays and Saturdays gives you a chance to meet growers face to face. There are other growers markets in our area, too.

If it's not possible for you to do that, consider joining a Community Supported Agriculture group. Through a CSA, you can order and receive farm-fresh produce, honey, meat, eggs and cheese. Many also offer the opportunity to visit the farms where the items are produced. For a list of local CSAs, Google THRIVE in Southern Oregon. It also publishes a booklet listing local CSAs.

Shop at a growers market this week and enjoy not only fresh, local produce, but many local artisans making items — from soap to hand-carved wood items. See you there!

Coming up: Bob Reynolds, Oregon State University urban horticulturist, will teach a class about the critters with whom we share our gardens, whether they wear fur or feathers. From 7 to 9 p.m. on Monday, June 9, he will discuss how to encourage those that are welcome and discourage those that aren't. The cost is $10. The class will be held at the Southern Oregon Research and Extension Center, 569 Hanley Road, Central Point. Call 541-776-7371 to register.

Carol Oneal is a past president of the OSU Jackson County Master Gardeners Association. Email her at diggit1225@gmail.com.