The world is now on the brink of a landmark new climate deal, as the COP21 UN climate talks in Paris near a climax.

Tensions in Paris are rising as countries race to resolve differences and forge an agreement to avoid the worst consequences of climate change.

Science reporter Jamie Morton speaks with Canterbury University researcher Dr Daniel Price.

Not every aspect of climate science is completely resolved, and here are five questions that are guaranteed to get the experts going.

The Herald's science reporter, Jamie Morton speaks with science writer and RNZ producer Veronika Meduna.

Herald science reporter Jamie Morton explains the ABCs of the COP21 conference.

What happens when you bring together close to 200 nations for one of the most pivotal summits in history? Organised chaos.

There's growing optimism in Paris over reaching a landmark agreement to spare future generations the worst impacts of climate change.

John Key has responded to more than 35,000 climate action marchers by smugly claiming that because 80 per cent of our electricity comes from renewable sources, we're respectable.

Tuvalu has issued a stern warning to its Pacific Island neighbours, urging countries not to do deals outside of the like-minded group at major climate talks in Paris.

Australia would support a UN review of restricting global warming to 1.5C, despite holding firm on a less ambitious goal.

With the UN climate talks under way in Paris, the Herald talks to Professor Dave Frame, of Victoria University's Climate Change Research Institute, about mitigation and reduction policy.

Currents are shifting, temperatures are climbing and the availability and dynamics of nutrient upwelling is changing.

New Zealand has picked up the embarrassing honour of being named the most regressive country at the Paris climate change talks, writes Sam Judd.

"I write this from my inner city Parisian hostel, nose still stinging from tear gas, sirens drowning out the background traffic noise."

Kiribati believes Australia is struggling with its position on climate change, preventing the nation from going into bat for its Pacific neighbours at major climate talks in Paris.

Mr Hughes cited Climate Action Network which said National had increased subsides to the oil, coal, and gas industries sevenfold since it was elected in 2008.

With the UN climate talks now underway in Paris, the Herald's science reporter Jamie Morton is talking to a range of experts on climate-related issues.

Jamie Morton talks to Professor Ralph Sims about how New Zealand might slash emissions in its energy and transport sectors.

Climate change rallies over the weekend throughout the country called for urgent action from a UN Climate Summit in Paris.

Jamie Morton talks to Professor Tim Naish about the major part the frozen continent has in the picture of climate change.

Green MP Julie Anne: "The march was incredible. Tens of thousands of people filling the streets of London, calling for a meaningful deal out of Paris. It's now up to the politicians to listen to those people and do the right thing over the next two weeks. This could be a watershed moment in the fight against dangerous climate change." Supplied: Green Party