Michael Sloan has been illustrating The Washington Post's Green Lantern column for a year and a half.  The feature answers reader's questions about the impact of a specific topic on the environment and the topics are always fascinating. Here are a few of Michael’s favorites from the 50+ assignments he’s completed:

Grass fed vs. corn fed beef

Food carts

Continuing destruction of the Amazon rain forest

The anniversary of the Exxon Valdez oil spill in Alaska

Chewing gum

Geothermal energy

India vs. China: Who pollutes the most?

Cheese making

Composting in the city

The impact of rocket launches on the atmosphere