The world's longest and most grueling competition is underway as competitors adventure 36,000 miles around the planet on sailboats.  

The race is intense — but it's not just about winning and glory. The sailors are also part-time citizen scientists competing on boats outfitted with tools that gather data on how climate change is impacting the world's oceans.   

The sailing competition, called The Ocean Race, started in January. Those competing started in Spain, then raced down the coast of Africa before cutting across the Indian and Southern oceans to reach Brazil. They then headed up the eastern coast of the Americas before crossing the Atlantic Ocean to get to Denmark. This week, the teams will leave Denmark on the final two legs of the race, which ends in late June in Italy

Charlie Enright, the skipper of a 60-foot long sailboat and leader of the 11th Hour Racing Team, the American competitors in the race, uses fin-like hydrofoils to propel his sailboat to speeds of up to 50 miles per hour. During the race, he and his team have fixed everything from torn sails to busted rudders, while using instruments on board the sailboat to gather data on climate change. 

Each team is working to track how climate change is impacting the oceans, which are rapidly warming from absorbing 90% of the excess heat created by planet-warming greenhouse gas emissions. Oceans provide about 50% of the oxygen humans breathe, making their health critical to human health.  READ MORE