1. Sanders linked climate change to national security in a national discussion on terrorism.

In the first Democratic debate following the Paris attacks, CBS moderator John Dickerson of “Face the Nation” questioned Bernie Sanders about his plans to rid the planet of ISIL.

"In the previous debate you said the greatest threat to national security was climate change," Dickerson began. "Do you still believe that?"

"Absolutely," Sanders said. "In fact, climate change is directly related to the growth of terrorism. And if we do not get our act together and listen to what the scientists say, you're going to see countries all over the world—this is what the CIA says—they're going to be struggling over limited amounts of water, limited amounts of land to grow their crops and you're going to see all kinds of international conflict."

While his remarks may have baffled some people, Sanders is right to relate climate change to the growth of terrorism and create a national dialogue about this overlooked relationship.

2. Sanders is the only anti-fracking candidate.

This week, the Sanders campaign released an ad exclusively to reiterate Bernie's stance on fracking. Actress and activist Susan Sarandon, an ardent supporter, narrates the spot.

"Do Washington politicians side with polluters over families?" Sarandon asked. "They sure do, because Big Oil pumps millions into their campaigns. Bernie Sanders is the only candidate for president who opposes fracking everywhere. Why? Because fracking pumps dangerous cancer-causing chemicals into the ground and threatens our drinking water."

New York banned fracking last June and votes in the primary April 19. However, fracking affects nearly half the nation's states.

3. Sanders sponsored the Rebuild America Act of 2015.

The Rebuild America Act of 2015 aims to improve watersheds, wastewater treatment, drinking water systems and create dams and levees to prevent flooding. It also seeks to set aside $3 billion a year to improve national parks, monuments, heritage areas and landmarks.

"The simple truth is that our infrastructure is collapsing and the American people know it," said Sanders. "For much of our history, the U.S. proudly led the world in building innovative infrastructure. Today, the U.S spends less than 2 percent of GDP on infrastructure, less than at any point in the last 20 years."

4. Sanders has a legacy of environmental protection, dating back to his years as mayor of Burlington, Vermont.

As the mayor of Burlington, Sanders scuttled plans to develop luxury 18-story condominiums and a 150-room hotel and "worked to create the public-use Waterfront Park on the shores of Vermont’s largest city," according to his website.

"We took the fight to the courts, to the legislature and to the people. And we won," Sanders said.

Environmentalists, including Bea Bookchin and Sandy Baird, sided with Sanders’ strong opposition in December 1985—and ultimately won “the best deal the city could expect to redevelop its then-derelict waterfront,” wrote Seven Days' Molly Walsh.

The "walkable mixed-use park includes a sailing center and marina, science center, bike path and public beach"—and is arguably the reason the area looks the way it does today.

5. Sanders received a near-perfect rating on environmentalism from the League of Conservation Voters.

On his national environmental scorecard, Sanders received a perfect score for 2015 and a lifetime score of 95 percent. He was just endorsed by Oregon senator Jeff Merkley, who also received a perfect score for 2015 and a lifetime score of 99 percent.

"After considering the biggest challenges facing our nation and the future I want for my children and our country, I have decided to become the first member of the Senate to support my colleague Bernie Sanders for president," Merkley told the New York Times today.

"From her time advocating for children as a young lawyer to her work as first lady of Arkansas and the United States and as a senator and secretary of state, Hillary Clinton has a remarkable record. She would be a strong and capable president," Merkley declared. "But Bernie Sanders is boldly and fiercely addressing the biggest challenges facing our country."

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