Obama and other leaders due in Paris for major climate change conference - CNN

Story highlightsU.S. and Chinese Presidents set to meet Monday morningBig climate march that was planned for Sunday is banned after terror attacksNearly 150 world leaders are expected to descend on Paris for the start of the U.N. climate change summit that starts Monday in the French capital with the aim of reaching a landmark global deal on limiting greenhouse gas emissions.

The leaders of the United States, China and India -- the world's top three carbon-emitting countries -- are among those scheduled to attend the opening day of the event, known as COP21.

It's being held amid heavy security after the deadly terrorist attacks that struck Paris two weeks ago. French authorities have clamped down on public demonstrations in the aftermath of the attacks, blocking environmental campaigners' plans for a big march on Sunday in Paris to highlight the climate change issue.

Refusing to be muted, some activists said they intended to cover the city's Place de la Republique with shoes to symbolize the steps that marchers were being prevented from taking. Demonstrations are also expected in other cities around the globe.

Opinion: Climate change is a form of terror

Obama to meet Chinese PresidentFrench President Francois Hollande is meeting with several world leaders Sunday ahead of the start of the two-week conference, including U.N. Secretary-General Ban Ki-moon and Chinese President Xi Jinping.

U.S. President Barack Obama is due to arrive in Paris late Sunday and meet with Xi the following morning.

"Clearly, U.S. cooperation with China is absolutely essential to successful efforts to combat climate change," White House Deputy National Security Advisor Ben Rhodes said in a briefing last week. "I think the two leaders meeting at the beginning of this process, as the two largest emitters, sends a strong message to the world about their shared commitment to combat climate change and to achieve an ambitious agreement."

More than 40,000 delegates from 195 countries are attending COP21, which has the goal of achieving a legally binding agreement to keep global warming below what most scientists say is the critical threshold of 2 degrees Celsius of warming.

5 things you need to know about COP21