150 Countries Will Sign Paris Climate Change Agreement on Earth Day

As the world celebrates Earth Day on Friday, more than 150 world leaders gathered at the United Nations headquarters in New York City to sign a historic climate change deal.

They are meeting to sign the Paris Climate Change Agreement, which aims to reduce greenhouse gas emissions quickly and help all countries build a sustainable future for their citizens. At the summit in Paris, also known as the COP21, the leaders accepted the science of climate change and agreed to work together to do something about it. More than 170 countries have expressed interest in signing the Paris pact; a final list of the leaders who committed will be available after the event Friday. The signing period will remain open for a year.

Each participating country has agreed to work toward limiting the temperature rise overall to below 2 degrees Celsius, and must submit detailed plans for how it will meet the goals of the pact. The agreement will be effective 30 days after the date when at least 55 parties have reached the full requirements.

"Today is a day to mark and celebrate the hard work done by so many to win the battle in securing the Paris agreement. Knowing what we know, this is also a day to recommit ourselves to actually win this war," U.S. Secretary of State John Kerry said during his speech to the U.N. Friday morning.

He called the Paris meeting a "turning point in the fight against climate change," and referred to the agreement as the "strongest, most ambitious climate pact ever negotiated." The power of the pact, he said, is the message it sends to the marketplace that innovation, allocation of capital and governments' decisions will define the new energy future.

"Nature is changing at an increasingly rapid pace due to our own choices," Kerry said.

The birth of the modern environmental movement came in 1970 with the first Earth Day celebrations in almost every major city and town in the country. The first massive nationwide protest against the pollution of the environment occurred that year on April 22.

NASA and the National Oceanic and Atmospheric Administration declared 2015 the hottest year on record by an unusually large margin. The record was set by a full tenth of a degree Celsius, which broke the previous record set just a year earlier, in 2014. In reports, the U.N. has warned the global threat of climate change will increase if leaders don't rein in the release of greenhouse gases into the atmosphere.

"The urgency of this challenge is only becoming more pronounced, and that is why our gathering today is in fact historic. The U.S. looks forward to formally joining this agreement this year, and we call on all of our international partners to do so," Kerry said. He signed on behalf of the United States just after 11 a.m. Eastern time.

Following the Paris agreement four months ago, a Reuters/Ipsos poll indicated that Republicans were less enthusiastic about fighting climate change than Democrats, with 91 percent of the latter party approving of the U.S. taking action. But more than half, or 58 percent, of Republicans approved of the country's involvement in the international deal.

The poll also found Republicans were split on whether they would support a presidential candidate who believes climate change is primarily man-made, with 30 percent saying they would vote for such a contender and 27 percent saying they wouldn't support that individual.

There is polarization about climate change among the five remaining candidates in the presidential race. Republican front-runner Donald Trump has said he isn't a "big believer in man-made climate change" and has called the hot-button issue a "hoax." His top opponent, Texas Senator Ted Cruz, has denied its existence, thus going against most scientists' beliefs.

On the Democratic side, both front-runner Hillary Clinton and Vermont Senator Bernie Sanders have made cutting greenhouse gas emissions part of their campaign platforms. Clinton specifically applauded Kerry and President Barack Obama for their help in delivering a new international agreement. As of 11:30 a.m. Friday, she was the only presidential hopeful to tweet about the pact and Earth Day.

Obama has made combating climate change, both at home and abroad, one of the key focuses of his presidency. But many of the contenders have criticized him for making it a national security issue, saying his view undermines the threat of terrorism.

Former Republican vice presidential nominee and Alaska Governor Sarah Palin took to Facebook Friday to warn against Obama "throwing America's opportunities to the back of the bus." The Paris agreement, she said, is "great news for China, India and everyone with low- to non-existent environmental standards eagerly producing the things we used to produce; it's sucky news for Americans trying to energize our homes, businesses and communities."

"We must be aware of big government cheerleaders' mission to stymie U.S. development and job opportunities by using bogus weather arguments that substitute real science for political b.s., all in the name of 'fundamentally transforming America,'" she said.