In this photo taken Oct. 25, 2010, Yakutian horses gather at the Pleistocene Park, a 40,000 acre wilderness in northern Siberia, Russia, where Russian scientist Sergey Zimov is trying to recreate conditions from the end of the Ice Age. Zimov believes populating Siberia with grass-eating animals will regenerate grasslands, which are more effective at preventing the thaw of permafrost and slowing the emission of dangerous greenhouse gases. (AP Photo/Arthur Max)

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In this photo taken Oct. 25, 2010, Yakutian horses gather at the Pleistocene Park, a 40,000 acre wilderness in northern Siberia, Russia, where Russian scientist Sergey Zimov is trying to recreate conditions from the end of the Ice Age. Zimov believes populating Siberia with grass-eating animals will regenerate grasslands, which are more effective at preventing the thaw of permafrost and slowing the emission of dangerous greenhouse gases. (AP Photo/Arthur Max)

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In this one hour exposure photo taken June 22, 2009 and provided by Steve Irvine, fireflies fly in front of his home in Big Bay, Ontario in Canada. A childhood rite of passage — catching fireflies in Mason jars and watching them glow — could be fading along with the dog days of summer. Scientists are busy analyzing a summer’s worth of observations of the mesmerizing insects collected by a network of backyard volunteers in hopes of verifying whether anecdotal evidence suggesting the luminous insects are on the decline is correct, and if so, what’s behind their shrinking populations. (AP Photo/Courtesy Steve Irvine)

In this one hour exposure photo taken June 22, 2009 and provided by Steve Irvine, fireflies fly in front of his home in Big Bay, Ontario in Canada. A childhood rite of passage — catching fireflies in Mason jars and watching them glow — could be fading along with the dog days of summer. Scientists are busy analyzing a summer’s worth of observations of the mesmerizing insects collected by a network of backyard volunteers in hopes of verifying whether anecdotal evidence suggesting the luminous insects are on the decline is correct, and if so, what’s behind their shrinking populations. (AP Photo/Courtesy Steve Irvine)

A scavenger on a boat collects recycleable items from garbage-strewn Citarum river in Bandung, West Java, Indonesia, Tuesday, June 8, 2010. (AP Photo/Kusumadireza)

A scavenger on a boat collects recycleable items from garbage-strewn Citarum river in Bandung, West Java, Indonesia, Tuesday, June 8, 2010. (AP Photo/Kusumadireza)

An oil-covered pelican tries unsuccessfully to fly off a post at Wilkerson Canal where it meets the north shore of Barataria Bay in Plaquemines Parish, Louisiana, Saturday, June 5, 2010. (AP Photo/Gerald Herbert)

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An oil-covered pelican tries unsuccessfully to fly off a post at Wilkerson Canal where it meets the north shore of Barataria Bay in Plaquemines Parish, Louisiana, Saturday, June 5, 2010. (AP Photo/Gerald Herbert)

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A brown pelican covered in oil from the Deepwater Horizon sits on the beach at East Grand Terre Island along the Louisiana coast on Thursday, June 3, 2010. (AP Photo/Charlie Riedel)

A brown pelican covered in oil from the Deepwater Horizon sits on the beach at East Grand Terre Island along the Louisiana coast on Thursday, June 3, 2010. (AP Photo/Charlie Riedel)

A brown pelican covered in oil from the Deepwater Horizon is seen on the beach at East Grand Terre Island along the Louisiana coast on Thursday, June 3, 2010. (AP Photo/Charlie Riedel)

A brown pelican covered in oil from the Deepwater Horizon is seen on the beach at East Grand Terre Island along the Louisiana coast on Thursday, June 3, 2010. (AP Photo/Charlie Riedel)

A brown pelican is mired in heavy oil from the Deepwater Horizon on the beach at East Grand Terre Island along the Louisiana coast on Thursday, June 3, 2010. (AP Photo/Charlie Riedel)

A brown pelican is mired in heavy oil from the Deepwater Horizon on the beach at East Grand Terre Island along the Louisiana coast on Thursday, June 3, 2010. (AP Photo/Charlie Riedel)

A Brown Pelican sits in heavy oil from the Deepwater Horizon on the beach at East Grand Terre Island along the Louisiana coast Thursday, June 3, 2010. (AP Photo/Charlie Riedel)

A Brown Pelican sits in heavy oil from the Deepwater Horizon on the beach at East Grand Terre Island along the Louisiana coast Thursday, June 3, 2010. (AP Photo/Charlie Riedel)

A Brown Pelican sits on the beach covered in oil from the Deepwater Horizon at East Grand Terre Island along the Louisiana coast on Thursday, June 3, 2010. (AP Photo/Charlie Riedel)

A Brown Pelican sits on the beach covered in oil from the Deepwater Horizon at East Grand Terre Island along the Louisiana coast on Thursday, June 3, 2010. (AP Photo/Charlie Riedel)

A bird is mired in oil from the Deepwater Horizon on the beach at East Grand Terre Island along the Louisiana coast Thursday, June 3, 2010. (AP Photo/Charlie Riedel)

A bird is mired in oil from the Deepwater Horizon on the beach at East Grand Terre Island along the Louisiana coast Thursday, June 3, 2010. (AP Photo/Charlie Riedel)

Bangladeshi boatmen row their boat through the polluted waters of the Buriganga channel on the outskirts of Dhaka, Bangladesh, Tuesday, June 1, 2010. World Environment Day 2010, which falls Saturday, calls for an urgent need to conserve the diversity of life on earth. According to United Nations Environment Programme website, a total of 17,291 species are known to be threatened with extinction. (AP Photo/Pavel Rahman)

Bangladeshi boatmen row their boat through the polluted waters of the Buriganga channel on the outskirts of Dhaka, Bangladesh, Tuesday, June 1, 2010. World Environment Day 2010, which falls Saturday, calls for an urgent need to conserve the diversity of life on earth. According to United Nations Environment Programme website, a total of 17,291 species are known to be threatened with extinction. (AP Photo/Pavel Rahman)

A view shows the business district in Hong Kong Monday, March 22, 2010. Hong Kong has been hit by record levels of severe air pollution. The government says this level corresponds to significant harm to human health. (AP Photo/Kin Cheung)

A view shows the business district in Hong Kong Monday, March 22, 2010. Hong Kong has been hit by record levels of severe air pollution. The government says this level corresponds to significant harm to human health. (AP Photo/Kin Cheung)

An Indian village boy runs through a parched field on World Water Day in Berhampur, Orissa state, India, Monday, March 22, 2010. Clean Water for a Healthy World is the theme for World Water Day 2010. (AP Photo/Biswaranjan Rout)

An Indian village boy runs through a parched field on World Water Day in Berhampur, Orissa state, India, Monday, March 22, 2010. Clean Water for a Healthy World is the theme for World Water Day 2010. (AP Photo/Biswaranjan Rout)

Mahendra Kumar surfaces to catch his breath as he dives into a polluted section of the River Yamuna to scavenge for ornaments and coins left by Hindu rituals at the river bank, in New Delhi, India, Monday, March 22, 2010. Officials say factories are ignoring regulations and dumping untreated sewage and industrial pollution, turning toxic the river that gives the capital much of its drinking water. (AP Photo/Gurinder Osan)

Mahendra Kumar surfaces to catch his breath as he dives into a polluted section of the River Yamuna to scavenge for ornaments and coins left by Hindu rituals at the river bank, in New Delhi, India, Monday, March 22, 2010. Officials say factories are ignoring regulations and dumping untreated sewage and industrial pollution, turning toxic the river that gives the capital much of its drinking water. (AP Photo/Gurinder Osan)