US makes key climate pledge to UN

The United States has pledged to cut its carbon emissions 26-28 per cent by 2025 as it submitted climate change pledges to the United Nations.

The formal offer to the UN was made in advance of a global agreement set to be signed in Paris in December.

The European Union has already promised to reduce its carbon emissions by a similar level.

Tuesday was the deadline for developed nations to make pledges – with some, including Canada, failing to submit by the deadline.

An announcement from the US said: "The target is fair and ambitious. The United States has already undertaken substantial policy action to reduce its emissions. Additional action to achieve the 2025 target represents a substantial acceleration of the current pace of greenhouse gas emission reductions. Achieving the 2025 target will require a further emission reduction of 9-11 per cent beyond our 2020 target compared to the 2005 baseline and a substantial acceleration of the 2005-2020 annual pace of reduction, to 2.3-2.8 per cent per year, or an approximate doubling."

Analysts assessing the first commitments made say they are not significant enough to restrict global temperature rise to the internationally agreed maximum of 2°C.

Wealthier nation were set the earlier deadline for submissions because the UN is determined for the UNFCCC Conference of Parties (COP21) in Paris to result in a historic international global climate deal.

The US announced the launch of a climate action plan in 2013 and introduced restrictions on power plant emissions and tougher standards on vehicles.

President Obama's policies, however, are being resisted by Republicans in Congress, and other nations have been watching closely to see if the pledge would be submitted.

The EU has pledged to reduce emissions 40 per cent compared to 1990 levels by 2030 with Switzerland and Mexico also unveiling pledges.