A U.S. environmental activist and a Russian meteorologist have won this year's Blue Planet Prize, a Japanese environmental award sponsored by the nonprofit Asahi Glass Foundation, its officials said Wednesday.

David R. Brower, 86, is former head of the U.S.-based Sierra Club and founder of Friends of the Earth and Earth Island Institute, while Mikhail I. Budyko, 78, is a Russian meteorologist who pioneered the science of climate change.

The Blue Planet Prize was established by the foundation in 1992 at the U.N. environmental summit in Rio de Janeiro. Two recipients are chosen annually for their contributions to solving global environmental problems. "I have seen human society face many challenges, but of all the battles of history, none is more important than the one we now fight to conserve, preserve and restore the natural world," Brower said in a released comment.

Brower is widely known for his active role in pressing authorities to abort a dam construction project planned at the Grand Canyon in the 1960s, and in establishing national parks in Kings Canyon, the North Cascades, the Redwoods, Cape Cod and Point Reyes.

Meanwhile, Budyko in 1972 published predictions of global climate change for the end of the 20th century and the first half of the 21st century. His predictions, based on increases and decreases in carbon dioxide concentration in the atmosphere, were later confirmed by observed data.

"I hope that in the future, Japanese and Russian scientists will maintain and further develop the close ties that have had great importance for me in my research activities," Budyko said in a released comment. Each of the two will receive a 50 million yen prize. They will come to Tokyo for the award ceremony on Oct. 29.