Why are NDCs important in global climate talks?

In the world's struggle to halt and reverse climate change, countries periodically report on their plans and progress in bringing down national levels of planet-warming carbon emissions.

These plans are called Nationally Determined Contributions, or NDCs for short.

WHAT IS AN NDC?

A country's NDC describes its national policies or decisions toward reaching net-zero emissions, and was updated every five years until delegates at the 2021 UN climate summit, COP26, in Glasgow called for more frequent updates every couple of years.

WHY WOULD WE BE HEARING ABOUT NDCs NOW?

The next round of NDC updates are due in February 2025, although some countries could announce plans during this week's UN General Assembly in New York.

Others might opt to share their newest plans during the upcoming UN climate summit, COP29, being held in Azerbaijan.

WHERE DID THE NET-ZERO GOAL COME FROM?

To avoid catastrophic climate extremes, countries agreed under the 2015 Paris Agreement to work together in limiting global warming to within 2 degrees Celsius of pre-industrial temperatures.

For that outcome, the world not only needs to reach net-zero emissions by 2050, but also needs to move fast in getting there - by cutting emissions roughly in half from 2005 levels within the next six years.

Instead, since the Paris pact, global emissions have continued to rise.

WHY ARE NDCs IMPORTANT?

While the Paris Agreement sets shared global emissions targets, each country decides for itself how to get there. They might consider policies for shifting how people power their homes, or how food is produced or cities designed.

More than 170 of the world's countries met the last NDC deadline ahead of COP26 in early 2021 with countries generally respecting the process - even if they are not equally ambitious and robust.

For this next round of NDCs, countries have been asked to focus on setting more ambitious near-term emissions targets for 2030 and for 2035.

WHAT ELSE SHOULD WE LOOK FOR IN THE NDCs?

Overall, an NDC is considered strong if it is detailed, ambitious, and credible. They should set emissions reductions targets for key polluting sectors, such as energy and transportation, while reconciling national policies that might frustrate progress in transitioning to clean energy, such as fossil fuel subsidies.

There should also be plans for how a country will monitor progress toward its NDC pledges.

The reports can also cover plans for adapting to the conditions of a warmer world and keep people safe from increased flooding, heatwaves and other climate extremes.

An NDC can detail projects to be launched, or plans for creating jobs in clean technology industries. It could include plans for public health measure amid increasing temperatures.

Countries with more developed NDCs that outline projects, policies and financing needs can help to attract funding.

But NDC reports can also describe backsliding on climate-friendly policy.

Last year, Britain's climate efforts were described by non-profit Climate Action Tracker as "insufficient" after the country's then government backtracked on key climate policies such as the near-term phase-out of new petrol cars and gas boilers in homes.

WHAT IF A COUNTRY FALLS SHORT?

Pledges made within an NDC are considered voluntary, with countries facing no legal penalty if they fail to meet their own goals.

However, they are obligated under the Paris Agreement to monitor progress and report on any failures.

Some countries like Britain and Chile have incorporated their NDCs into national law, making their climate commitments legally binding at a national level.

But while NDCs are not designed to be legally binding, countries can still face litigation for falling short.

Europe's top human rights court agreed in April with a group of Swiss women saying their government had violated their human rights by not doing enough to combat climate change.