Just two years after a rare, eye-opening voyage through the Northwest Passage, Iowan David Thoreson is attempting to circumnavigate North and South America in a continuous sailboat trip – something that’s never been done before.

The 13-month voyage, which launched Sunday in Seattle, promises gut-wrenching dangers and personal costs. But at age 49, Thoreson has found his life’s purpose on the planet’s edges.

Far from the serene waters of his home near Lake Okoboji, where he steered his grandfather’s 5-horsepower fishing boat as a youngster, Thoreson and three other sailors have a goal greater than the explorer’s ego-building firsts: Draw attention to the planet’s peril from global warming and pollution.

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