When we hear about people using biomass for fuels in the news, we tend to hear the stories of innovators making progress on greener energy technology: a Dutch biomass plant using chicken manure to power 9,000 homes, the world's largest biomass plant opening in Florida, and so on. It seems like a promising way to provide energy to the masses, right?

But consider that 2.5 billion people across the world are already using biomass?animal feces, charcoal, wood scrap—to generate heat for their cook stoves. Unfortunately, they do it out of necessity and at risk to their own health. According to GlobalIssues.org, half of the people in both India and China, as well as 80% of the population in Sub-Saharan Africa rely on traditional biomass for cooking.

Although the concept of reusing materials like dung and crop waste is a sustainable one, burning both creates harmful byproducts. Using a biomass cook stove indoors generates a ton of unwanted indoor air pollution, and is thought to kill over 1.6 million people every year. What's more, impoverished people foraging for wood leads to mass deforestation.

Thankfully, there seems to be a simple solution: better cook stoves. The nonprofit org Envirofit produces efficient biomass cook stoves that reduce indoor air pollution and fuel usage. They still run on the likes of feces and crop waste, and they reduce indoor pollution by up to 80%, while reducing fuel usage by 50%. Those are some pretty vast improvements on a seriously growing issue. So if you're looking for a worthy charity to donate to, look into Envirofit.