Here are five of the best quotes Thursday from the UN climate conference in Paris, which aims to forge a universal pact to curb global warming:

James Hansen, one of the world's foremost climate scientists, when asked about a target being discussed in Paris of curbing global warming to 2 degrees Celsius (3.6 degrees Farenheit) above pre-Industrial Revolution levels:

"Two degrees Celsius warming above pre-Industrial would put us at least at the temperature of the last inter-glacial period. Sea level was six to nine metres (20-30 feet) higher then. That means every coastal city would become disfunctional. We build our cities with the coastlines that have existed for the last 10,000 years. So half of the major cities in the world are on coastlines. If we let ice sheets become unstable, the world may become ungovernable because the economic consequence would be so great."

South African negotiator Nozipho Mxakato-Diseko ridicules a draft text that says all countries "in a position to do so" will help finance a shift to clean energy:

"In my family with the children I will tell them: 'You will clean, so and so. You will clean the room'. I do not say that 'someone will clean the room'. I say: 'You, John, will clean the room. You, Grace, will do the dishes'. There is no 'Someone in the position to do so will sweep the floor'. I need accountability and I need to know above all that the floor has been cleaned."

The World Wide Fund for Nature's head of delegation, Tasneem Essop, says negotiators need to pick up the pace if they are to reach a deal in Paris by the scheduled end of the conference on December 11:

"Right now, they're still just rearranging the deck chairs on the ship to get a better view of the iceberg."

President Anote Tong of the Pacific island nation of Kirabati, which risks slipping below the waves as sea levels rise, complaining about the short-term interests of lawmakers:

"Politicians don't have a lot of compassion, they don't always have a conscience, but they have elections."

High-profile rights activist Bianca Jagger who is in Paris to lobby for action at the climate talks:

"We can no longer pretend that we're doing everything to save the planet, to prevent catastrophic climate change, and I keep using that word because I think it's important for all of us not to be deluded."