Costa Rica's NatureAir, which four years ago became the world's first carbon-neutral airline, has now signed on to the Climate Neutral Network, an initiative of the UN Environmental Program.

"With the airline industry contributing an estimated three percent of global greenhouse gas emissions - nearly as much as the entire African continent, it is vital that solutions to the climate change challenge come from within the industry itself. I welcome NatureAir to the Climate Neutral Network as a trailblazer on the path to zero emissions air travel," said UN Under-Secretary-General and UNEP Executive Director Achim Steiner.

NatureAir offsets all of its carbon emissions -- no small feat, even for a small airline with efficient propellor planes -- by purchasing credits from the government, which go toward protecting the country's hundreds of acres of tropical forests. The increasingly popular airline has found that flying green is not only environmentally friendly; it's also quite profitable, as NatureAir has grown an average of 20% annually since 2001.

So if you happen to be travelling in Costa Rica -- a country aiming to become the world's first entirely carbon-neutral nation -- hop aboard one of NatureAir's colorful, climate-friendly planes. And unlike the even smaller prop planes of its competing "puddle-jumper," NatureAir can also fly in the rain.

(photo from flickr user Matt Stratton under a Creative Commons license)