As the Paris COP21 accord with its unprecedented collective global response to climate change was being ratified on Saturday evening, it was inevitable that the responses from leading politicians and environmentalists tended to nod towards the historic.

The president of the COP21 Summit, French foreign minister Laurent Fabius, made an extraordinary and emotional speech when he presented the final text earlier on Saturday, drawing on the words of a towering figure of the 20th century.

He quoted Nelson Mandela’s dictum - “It’s always impossible until its done” - reflecting the seemingly insuperable objects that had been overcome over the past fortnight.

‘Deep conviction’

“It is my deep conviction that we have come up with an ambitious and balanced agreement,” he said.

Shortly before 7.30pm local time, Mr Fabius struck the gavel to declare the Paris Agreement ratified - to thunderous applause.

He was joined on stage by French President François Hollande, UN secretary general Ban Ki-Moon, United Nations Framework Convention on Climate Change (UNFCCC) head Christiana Figures and the senior French diplomat who headed the COP21 secretariat, Laurence Tubiana.

Former US vice-president Al Gore, former president of Ireland Mary Robinson and French ecology minister Ségolène Royale were also in attendance.

The reaction to the accord reflected the nature of the compromise. The final agreement was delayed by 24 hours after last-minute wrangling over transparency and long-term goals, believed to have involved China, India and Saudi Arabia.

One of the leading players in the negotiations, South African environmental affairs minister Edna Molewa, who spoke on behalf of the developing G77 group and China, also quoted Nelson Mandela at length when highlighting the shortcomings of the agreement.

"Mr Mandela said and I quote: 'I have walked that long road to freedom. I have not faltered. I have made mis-steps along the way but I have discovered the secret that after climbing a great hill, one only finds that there are many more hills to climb.

‘Glorious vista’

“I have taken a moment here to rest, to steal a view of the glorious vista that surrounds me, to look back on the distance I have come. But I can only rest for a moment, for with freedom come responsibilities, and I dare not linger, for my long walk is not ended.”

The US secretary of State John Kerry said: "It's a victory for all of he planet and for future generations. The world has come together around an agreement that will empower us."

He added: “It will ultimately prevent the worst most devastating effects of climate change from ever happening.”

China’s lead representative Xie Zhenhuat said it was “true the agreement is not perfect and some areas are in need of improvement”.

He said developed countries would need to honour their commitments to developing countries. China is still a developing country but is currently responsible for 28 per cent of all global emissions.

Mr Ban was expansive in his comments: "The issues are many and complex. But we must not let the quest for perfection become the enemy of the public good," he said.

Head of the EU negotiation team, energy commissioner Miguel Arias Cañete, praised France and said COP21 was a truly historic process and a tremendous collective achievement. He said the EU would scale up financial support from 2020 to developing countries and make that funding predictable.

‘Tomorrow we act’

“Today we celebrate. Tomorrow we have to act,” he said.

Irish political reaction was positive. Minister for the Environment Alan Kelly said: "We are on the cusp of history. The deal is by no means perfect, but having a deal signed by so many countries will be historic.

“This was among the most important gatherings in world history. I am proud to have played my part as part of the EU team in making it possible.

“We are no longer debating whether climate change is real, we are trying to agree on how to tackle it. The next generation would not forgive us if this deal was not done.”

Speaking from Paris, Green Party leader Eamon Ryan said it signalled the beginning of the end for the fossil fuel era.

“We now have a new consensus where every country agrees to ramp up actions to avoid dangerous climate change. This means leaving fossil fuels in the ground and switching to a more sustainable economic model.

“It is not perfect. We agree with those climate scientists who say it does not go far enough and we need a much stricter carbon budget. We also share the concern of those who say not enough is being done to help the poorest countries,” he said.

The response of civic society, including environmental campaigners, was on the whole positive, although there were discordant notes sounded about the poorest and most vulnerable countries being left somewhat short.

Tim Gore of Oxfam was one of those who voiced caution.

“The major powers have come together and the poorest have been short-changed. [The accord] gives a fragile lifeline for the most vulnerable.”

He said the 1.5 degrees target might “ring hollow unless we see a significant increase in action in the years ahead”.

Largely positive

The reaction from environmental and aid agencies was largely positive.

Mohamed Adow of Christian Aid said for the first time in history, the "whole world has made a public commitment to reduce greenhouse gas emissions and deal with the impacts of climate change".

Kumi Naidoo, executive director, Greenpeace International said: "The wheel of climate action turns slowly, but in Paris it has turned. This deal puts the fossil fuel industry on the wrong side of history."

Bill McKibben of 350.org asserted that despite the progress, the “power of the fossil fuel industry is reflected in the text, which drags out the transition so far that endless climate damage will be done”.

Sorley McCaughey of Christian Aid said: “This deal must echo through boardrooms and stock exchanges around the world. The era of dirty investments is over. The profitable, forward-looking business opportunities of the future lie in clean investment.”