Buying out of season food is as good as guzzling gas. Here's how:
Let's say you want a tomato, but where you live, tomatoes aren't in season. You'll have to get a tomato from the grocery, and if you live in the United States, your grocer likely sells tomatoes that came from either Florida or Mexico. This tomato was picked green, so it wouldn't rot during transit, and traveled to your grocery store via an 18-wheeler truck. Once it arrived in your area, it likely was placed in a warehouse where it was gassed with ethylene to force it to ripen artificially.
On the other hand, if you buy a tomato in season from a local farmer, it likely ripened on the vine before it was plucked and traveled a short distance, saving tons of carbon emissions. Your tomato also tastes better. Why? Tomatoes need sunlight to produce sugar, which gives them their signature sweet, rich taste. If your tomato was picked when it wasn't ripe, it'll taste more like water.