U.N. Framework Convention on Climate Change COP21 negotiations

World leaders are due to agree on a new global deal to tackle climate change at the 2015 U.N. climate conference (known as COP21), to be held from Nov 30 to Dec 11 in Paris. If an agreement is reached, it would replace the current international treaty, the Kyoto Protocol.

The stakes are high after the failure of an earlier attempt in Copenhagen in 2009.

The backbone of a deal in Paris will be national offers put forward by each country, setting out what they plan to do to reduce or curb their greenhouse gas emissions. They are now in the process of preparing and submitting their offers, known as Intended Nationally Determined Contributions (INDCs), in time for the U.N. climate change secretariat to review them before Paris.

Developing countries are also likely to include their plans to adapt to growing climate change impacts, and possibly how much financial and technical support they will need to adapt and to pursue low-carbon growth. 

A new deal in Paris will not come into effect until 2020, so countries will also discuss at the summit their plans for ramping up climate change action before then.

Many experts are warning that any new climate change agreement is unlikely to be ambitious enough to hold global temperature rise to 2 degrees Celsius above pre-industrial levels, as governments have promised to do.

The hope is that the agreement will also include a mechanism for strengthening targets and actions on a regular cycle, such as every five to 10 years, to keep to that temperature limit.

Climate finance for developing nations will also be in focus, as it remains unclear how public and private flows will be boosted to meet a non-binding goal of $100 billion a year by 2020, agreed in 2009.

Another key issue is the legal form of a new deal - which remains open for discussion. Some parts of the agreement may be legally binding and others not, with some countries such as the United States reluctant to sign up to a deal that would require new national-level legislation on climate change.