Ensia is a solutions-focused media outlet that publishes stories that encourage and inspire people to create a more sustainable future. They consider proposals for articles and feature stories that “provide solution-focused perspectives on emerging environmental challenges as well as novel ways of looking at long-standing issues.” Their articles are of about 700 to 750 words, and feature stories are of about 1,000 to 1,200 words. According to a payment report, they paid $0.75 per word. For details, read their contributor guidelines and visit this page. The last time we checked they were not accepting pitches, but may re-open at some point.