Right! Aside from walking or biking, taking the train is the most environmentally friendly way of traveling. In fact, compared to cars and airplanes, trains emit between 66 and 75 percent less carbon. In terms of energy consumption, use of space, and noise levels, trains are far more sustainable too.

Grey water is water that's too dirty to drink or bathe in, but not so dirty that it's unsafe to use for flushing toilets or other noncontact household tasks. Some innovative researchers are exploring ways to get more use out of grey water.

An e-reader represents not just one book but an entire bookshelf, so having more books on the e-reader reduces the environmental burden per book. ... If you read a limited number of books, the paper book will most likely limit your greenhouse gas emissions. But for heavy readers, e-books have a smaller carbon footprint.

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The interlinkages between air pollution and climate change provide an opportunity to amplify the benefits of our action and catalyst even greater mitigation ambition, Plans ans strategies to rapidly reduce warming, must therefore integrate actions to reduce all air pollutants and greenhouse gases that contribute to both near0 and long-term climate impacts. This will put the world on a trajectory that maximizes benefits, reduce the risk of policy failure, and delivers national development priorities.