'The diplomats have done their job'

Scientists, business leaders and politicians around the world are reacting to the Paris Agreement - the first to commit all countries to cut carbon emissions.

Delegates from nearly 200 countries unanimously agreed to the deal today after gruelling negotiations at the UN's COP21 climate change conference in the French capital.

The main aim of the agreement is to keep global temperature rises "well below" 2°C, with an aspirational target of limiting the rise to 1.5°C.

Some aspects of the agreement will be legally binding, such as submitting emission reduction targets and the regular review of those goals.

However, under the deal reached today, the targets set by nations will not be binding - and some scientists have said complete safety is not guaranteed even if the 2°C limit is successfully met.

Broad international support

US President Barack Obama hailed the agreement as strong and historic, calling it the best chance to save the planet from the effects of global climate change.

It sent "a powerful signal" that a low-carbon future and investment in clean energy were economically viable and could create jobs, he said.

However, he added, the individual country targets pledged so far would not be enough.

"Even if all the initial targets set in Paris are met, we'll only be part of the way there when it comes to reducing carbon from the atmosphere."

China and India said before the adoption of the agreement that they supported its draft proposals.

Indian Environment Minister Prakash Javadekar said the deal opened a "new chapter of hope" in the lives of the world's billions of inhabitants.

"We have [the planet] on loan from future generations. We have today reassured these future generations that we will all together give them a better earth.

European Commission President Jean-Claude Juncker also described the deal as a lifeline for future generations, and expressed hope for a "global clean energy transition".

The Least Developed Countries (LDC) Group, which represents 48 nations in Africa, Asia and the Pacific, said in a statement the deal was the best outcome the group could have hoped for.

"We are living in unprecedented times, which call for unprecedented measures. Nothing that has gone before compares to this historic, legally binding climate agreement," it said.

Marshall Islands Foreign Affairs Minister Tony de Brum praised the deal on Twitter.

"Climate change won't stop overnight, and my country is not out of the firing line just yet, but today we all feel a little safer."

He said he could now go back to his people and tell them they had a "pathway to survival".

Australian Foreign Minister Julie Bishop said no country would see the deal as a perfect outcome.

"However, this agreement does give us a strategy to work over coming years and decade to build the strong and effective action the world needs."

Reaction in New Zealand

In New Zealand, Climate Change Issues Minister Tim Groser said the deal served this country's interests as a resource-dependent and export-dependent nation well.

He said New Zealand's target of reducing emissions to at least 30 percent below 2005 levels by 2030 was a strong contribution to global efforts.

Opposition MPs welcomed the deal but challenged the government on its record and said it needed to do more at home to meet its new international obligations.

Professor Tim Naish is the director of Victoria University's Antarctic Research Centre.

"The universal commitment by governments to a mitigation pathway that restricts global warming to 2°C with ambition to stabilise at 1.5°C is an extraordinarily good outcome, even although the details of a plan to get there are yet to be agreed upon," he said, in one of a series of reactions published by the Science Media Centre.

"While the current science says 2°C is not completely safe, it does appear to be a guardrail below which risks are considerably reduced."

The most positive outcome of the Paris climate talks might have occurred outside the plenary rooms, Massey University Centre for Energy Research director Professor Ralph Sims said.

"The momentum of businesses, cities, NGOs, financiers, bankers, indeed across all civil society, in their intent to move towards a rapid transformation to a low-carbon economy was far more impressive than the formal negotiations."

Next steps

Columbia University Earth Institute director Jeffrey Sachs stressed the importance of organisations and individuals outside politics taking action.

"The diplomats have done their job: the Paris Agreement points the world in the right direction, and with sophistication and clarity," he said.

"It does not, however, ensure implementation, which necessarily remains the domain of politicians, businessmen, scientists, engineers, and civil society."

International Monetary Fund chief Christine Largarde used her statement following the deal to call for carbon pricing.

"Governments must now put words into actions, in particular by implementing policies that make effective progress on the mitigation pledges they have made. That is why my key message is to price carbon right and to do it now."

Unilever CEO Paul Polman said the deal sent an "unequivocal signal" to the business and financial communities.

"The billions of dollars pledged by developed countries will be matched with the trillions of dollars that will flow to low carbon investment."

- RNZ / Reuters / ABC / BBC