"The Paris Climate Change Conference is going ahead and all the related events are going ahead. That's the bottom line," said Janos Pasztor, UN Assistant Secretary-General on Climate Change, at the UN headquarters on Friday.

"World leaders, one after another, are reconfirming that they are going to Paris on Nov. 30, because they think this is an important event. They will be there to support the climate negotiations," said Pasztor. "People intend to go to these meetings and intend to show solidarity with France."

On whether the topic of terrorism may take the spotlight from climate change during the upcoming summit, Pasztor said "It is inevitable when there are such major political issues, leaders will talk about issues that are important."

Assistant Secretary-General expressed his optimism about a much-anticipated climate deal to be reached at the 2015 United Nations Climate Change Conference, which will be held in Paris, from Nov. 30 to Dec. 11

"I am realistic and I am optimistic. When you put everything together, we know that we still have a long way to go between now and the Dec. 11, because there is a lot that still needs to be negotiated and finalized." he said. "At the same time, the stars are lining quite well. I am optimistic that it is possible to have a strong agreement."

He explained that "All the governments really want an agreement, partly because they are been pressured by the voters. Climate change is no longer just a future thing out there. It is happening and in many places, it is visible today."

On China's commitment to tackle climate change, Pasztor told Xinhua that "The bilateral declarations of China with the United States and France are very significant inputs to the multilateral process."

"It clearly shows that China is not just an active participant but a proactive and a very constructive participant in the multilateral process by engaging with difference countries," he said.

Harvard professor Robert Stavins told Xinhua in an email interview that "I am very impressed by the changes we have seen coming from China in regarding to climate change policy."

"The two joint statements with the United States (one in November 2014 and another in September 2015) have been path-breaking," Stavins added.

On Nov. 2, President Xi Jinping and his French counterpart Francois Hollande issued a joint statement on climate change, vowing to promote a working program to accelerate pre-2020 efforts in mitigation, adaptation and support during the Paris climate summit.

They called for a better transparency system to build trust and confidence in the Paris pact, as well as means to review the actions and support of various parties.

In September, the joint statement between China and the United States reaffirmed the commitment of the two sides to reach an ambitious agreement in 2015 that reflects the principle of common but differentiated responsibilities and respective capabilities.