The USDA has unveiled a new color-coded map of planting zones showing average low temperatures across the country. It’s the first update since 1990, and it shows a hotter 21st century. Nearly entire states, such as Ohio, Nebraska and Texas, are in warmer zones.

(Photo: AP/USDA)

What if greenhouse gases weren’t invisible? Would we have started to regulate them long ago — like we do with other emissions we can see?