Prime Minister David Cameron is among those who have gathered at the event, where the idea of charging the most polluting companies and countries is expected to dominate.
CAFOD's Neil Thorns is also hoping a joint statement – which was presented to the UN secretary general before today's meeting by faith leaders from around the world, who met in New York before Tuesday's summit – will put pressure on politicians to make progress on the issue.
Speaking on Premier's News Hour from New York, he said: "I think they were sending a strong statement to the leaders to say, as people of faith, this is something which we believe in through our faith but also the impact it's having on our brothers and sisters across the world already."
Titled Climate, Faith and Hope: Faith Traditions Together for a Common Future, it calls on "all States to work constructively towards a far-reaching global climate agreement in Paris in 2015, which will be ambitious enough to keep temperature from rising well below 2° Celsius; fair enough to distribute the burden in an equitable way; and legally binding enough to guarantee that effective national climate policies to curb emissions are well funded and fully implemented".
The NGOs, which include CAFOD, CARE International, Christian Aid, Greenpeace, Practical Action and WWF UK, say they want to see the sustainable development goals (SDGs) – the expected successors to the millennium development goals, which expire at the end of 2015 – to include a standalone goal to tackle climate change.
The NGO report highlights the crucial role a new set of sustainable development goals must play in meeting the challenge.
It says that the goals, to be agreed next year, offer a vital opportunity for the international community to tackle the way climate change is driving people into poverty.
The work comes in response to the latest findings of the Intergovernmental Panel on Climate Change (IPCC), the leading authority on climate science, which has warned that climate change is a massive threat to poverty reduction and sustainable development.
Hear more from CAFOD's Neil Thorns: