LE BOURGET, France (AP) — Some 150 world leaders including President Barack Obama are joining U.N. Secretary-General Ban Ki-moon Monday in kicking off two weeks of high-stakes climate talks near Paris, with organizers hoping the unprecedented high-level appearances will turbocharge the chances of reaching an ambitious deal to cut emissions that are warming the planet.

The meeting comes at a somber time for France and many of the visiting leaders, two weeks after extremists linked to the Islamic State group killed 130 people around Paris. Immediate fears of repeat attacks have prompted extra-high security and a crackdown on environmental protests — and threaten to eclipse longer-term concerns about rising seas and increasingly extreme weather linked to man-made global warming.

Ban and French President Francois Hollande greeted heads of state and government from around the world as they arrived for the talks, shaking hands outside the conference center near the Le Bourget airfield just north of Paris. Alongside them stood the head of the U.N. climate change agency Christina Figueres and French Environment Minister Segolene Royal.

Each leader will then give a speech about what their countries are doing to reduce emissions and slow climate change. After the leaders leave, negotiators have two more weeks to work on a deal before the talks are scheduled to wrap up Dec. 11.

The conference is aimed at the most wide-reaching deal ever to tackle global warming. The last major agreement, the 1997 Kyoto Protocol, only required rich countries to cut emissions, and the U.S. never took part.

Among several sticking points is money — how much rich countries should invest to help poor countries cope with climate change, how much should be invested in renewable energy, and how much traditional oil and gas producers stand to lose if countries agree to forever reduce emissions.

With that in mind, Bill Gates, Obama and other world leaders are announcing a plan Monday for governments and business leaders to invest billions of dollars to research and develop clean energy technology.

A key goal is to bring down the cost of cleaner energy. At least 19 governments and 28 leading world investors, including Facebook founder Mark Zuckerberg, billionaires George Soros and Saudi Prince Alaweed bin Talal, and Jack Ma of China's Alibaba, have signed on so far.

"It's quite a big deal," said Jennifer Morgan, global climate director for the World Resources Institute. "It brings a new kind of burst of energy into the conference right at the beginning on something very important."

The new initiative is twofold: a public-private project called Mission Innovation, led by governments, and the Gates-led investor group called the Breakthrough Energy Initiative.

Under the initiative, the governments of the U.S., India, China, Indonesia, Japan, Saudi Arabia, Mexico, Norway, Sweden, Britain, France, South Korea, Denmark, UAE, Australia, Canada, Brazil, Chile and Germany pledge to double their spending on low or no-carbon energy over the next five years.

The 19 countries currently invest about $10 billion a year total, about half of which comes from the U.S., Brian Deese, senior adviser to Obama on climate and energy issues, told reporters in Washington.

Gates committed $1 billion of his money and was the "intellectual architect" behind the effort to get investors involved, U.S. Energy Secretary Ernest Moniz said. The business leaders are making their pledges conditional on governments also pledging more money, said a former U.S. government official who is familiar with the plan.

But the project could create intellectual property problems, and it's unclear whether the future funding will be approved in U.S. or other budgets.

Obama, who arrived in Paris late Sunday night, wrote on his Facebook page that "we'll work to mobilize support to help the most vulnerable countries expand clean energy and adapt to the effects of climate change we can no longer avoid."

Obama paid a late-night tribute to those killed in the attacks in Paris two weeks ago, shortly after arriving in the French capital. Placing a single flower at a makeshift memorial, Obama bowed his head in silence.

Wide Paris-area highways usually packed with commuters are cordoned off to clear the way for all the VIPs. Riot police vans and plainclothes officers are stationed around the capital and by the national stadium Stade de France, which was one of the targets of the Nov. 13 attacks and is near the climate conference venue.

___

Sylvie Corbet, Karl Ritter and Nancy Benac in Le Bourget and Stacey Anderson in Washington contributed.