Can UN climate change talks save the world from crisis?

At the UN climate change talks later this year, a new protocol called COP21 is set to be adopted at the meeting, to replace the 1997 Kyoto Protocol that is due to expire. The protocol requires countries to reduce greenhouse emissions as global-warming in increasing due to human-made carbon-dioxide emissions.
Scientists say that in order to prevent the 2 degree warming, the Earth should completely stop carbon-dioxide emissions. With the current state of pollution, the planet could face 2.9 to 3.1 degree warming, according to Climate Action Tracker.