French President Francois Hollande gestures when posing with world leaders for a photo during the opening day of the World Climate Change Conference 2015 near Paris.(JACKY NAEGELEN / AFP/Getty Images)
Russian President Vladimir Putin delivers a speech as he attends Heads of States’ Statements ceremony of the COP21 World Climate Change Conference 2015 north of Paris.(ETIENNE LAURENT / EPA)
President Barack Obama smiles during the inaugural session of the COP 21 United Nations conference on climate change on the outskirts of Paris.(ERIC FEFERBERG / AFP/Getty Images)
From left, French Minister of Ecology, Sustainable Development and Energy Segolene Royal, French President Francois Hollande, and Secretary-General of the United Nations Ban Ki-moon, arrive for the COP21 World Climate Change Conference 2015 north of Paris.(LOIC VENANCE / POOL / EPA)
A police officer and his dog check photgrapher’s bags during the COP21 near Paris. World leaders are meeting in Paris for the start of COP21, the two-week UN climate change summit, attempting to agree on an international deal to curb greenhouse gas emissions.(Pascal Le Segretain / Getty Images)
A couple wear protective masks as they walk outside the Forbidden City on a day of heavy pollution in Beijing. The representatives of the governments of more than 190 countries are meeting in Paris this week to set targets on reducing carbon emissions in an attempt to forge a new global agreement on climate change.(Kevin Frayer / Getty Images)
Declaring that the future of the planet is at stake, more than 150 world leaders assembled outside Paris on Monday to launch an ambitious attempt to confront climate change by reducing greenhouse gas emissions.
After decades of difficult negotiations and an unsuccessful attempt to strike a deal six years ago, President Obama said a turning point may have been reached.
“What should give us hope,” he told fellow leaders, “is the fact that our nations share a sense of urgency about this challenge and a growing realization that it is within our power to do something about it.”
The United Nations conference comes at a time of record high temperatures, more extreme droughts and storms, shrinking glaciers and melting ice packs — events that have helped make climate science more widely accepted. That, coupled with major advances in cleaner energy sources, has increased the willingness of some of the world’s biggest polluters to act.
The leaders of nations responsible for more than 95% of the world’s greenhouse gas emissions arrived at the conference at Le Bourget, on the northern edge of Paris, armed with plans to reduce their outputs.
But the proposals on the table are not projected to achieve the target of limiting rising global temperatures to 2 degrees Celsius above preindustrial levels, the threshold at which scientists believe most of the worst effects of climate change could be avoided. Organizers say countries will need to do more.
“The future of your people, the future of the people of the world, is in your hands,” U.N. Secretary-General Ban Ki-moon told leaders as the talks kicked off. “We cannot afford indecision, half measures or merely gradual approaches. Our goal must be a transformation.”
The high-level meeting began with a moment of silence for the victims of deadly attacks in France, Lebanon, Tunisia and elsewhere — a wave of violence that threatened to overshadow longer-term concerns about climate change.
“These tragic events … force us to concentrate on the essentials,” French President Francois Hollande said. “We must leave our children more than a world free from terror. We must leave them a planet that is preserved from catastrophes, a viable planet.”
The biggest issue facing the 151 heads of state and government at the summit is who should bear most of the burden of closing that gap: wealthy Western nations that have polluted the most historically, or developing countries such as China and India, now the biggest and third-biggest emitters of greenhouse gases?
Major issues still have to be resolved, however, including who should assume the cost of shifting the world’s economies to solar, wind and other renewable energy sources.
Developing countries have long argued that the burden should fall on the countries that got rich through the use of fossil fuels.
Severe air pollution has helped persuade China and India to seek to reduce their reliance on coal-fired energy. As the summit got underway, their capitals were blanketed in smog; Beijing issued an “orange” pollution alert, the second-highest level.
Still, Chinese President Xi Jinping said the deal reached in Paris must recognize differences between developing and more established economies, and include aid for poor countries.
“Addressing climate change should not deny the legitimate needs of developing countries to reduce poverty and improve living standards,” he said.
Indian Prime Minister Narendra Modi said developed nations could make the biggest difference on the environment. “National commitments must be consistent with the carbon space nations occupy,” he said.
Wealthier nations also have a responsibility to make cleaner energy affordable and accessible in the developing world, he said. “This is in our collective interest,” he said.
Many leaders who spoke Monday want the agreement to include legally binding targets. That could be a deal-breaker for the U.S., which needs approval from the Republican-controlled Senate to sign a binding treaty.
In his address to the conference, Obama acknowledged that taking strong action on the environment has not always been a political winner. But he noted that the U.S. and other global economies have grown even as fossil fuel emissions have leveled off.
“We have proved that strong economic growth and a safer environment no longer have to conflict with one another,” he said. “And that should give us hope.”
Speaking at a heavily guarded conference center, Obama said the determination of world leaders to act as one in pursuit of a common goal was itself a rebuke to the Islamist extremists who killed 130 people in Paris two weeks ago.
The president highlighted steps that his administration has taken to curb emissions, and praised the many other nations that have committed to do the same in the lead-up to the summit.
“Our task here in Paris is to turn these achievements into an enduring framework for human progress — not a stopgap solution, but a long-term strategy that gives the world confidence in a low-carbon future,” Obama said. “That’s what we seek in these next two weeks, not simply an agreement to roll back the pollution we put into our skies, but an agreement that helps us lift people from poverty without condemning the next generation to a planet that’s beyond its capacity to repair.”
By inviting Obama and other leaders to the opening days of the summit, organizers hoped to send a clear signal: Paris is not Copenhagen.
In 2009, a similar effort to reach a binding agreement to address climate change had all but collapsed by the time Obama and his counterparts arrived in the Danish capital near the conclusion of that summit.
Officials hope the participation of world leaders at the start of this year’s conference, with commitments for action in hand as they arrive, will provide the momentum needed to reach a strong accord, even if it falls short of the 2-degree target.
A number of initiatives were announced by governments and private investors Monday, including billions of dollars in investments to support the development and adoption of clean energy technologies and help the most vulnerable countries cope with the effects of climate change.
French Foreign Minister Laurent Fabius, who took over as president of the negotiations Monday, reminded participants that they have just “11 short days” to reach an agreement.
“Success is not yet assured, but it is within our grasp,” he said. “The eyes of the world are upon us.”
Special correspondent Christina Boyle in London contributed to this report.
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