How climate summit pledges may, or may not, affect heating

The Paris Agreement commits nations to limit temperatures to 'well below' 2C and to work towards a safer 1.5-C cap

After a week of negotiations filled with grand announcements from nations promising to accelerate the decline of fossil fuels, where do the pledges put projected emissions halfway through the COP26 climate summit?

Countries came in to the UN-led negotiations with their latest national emissions cutting pledges -- known as nationally determined contributions, or NDCs -- placing Earth on course to warm 2.7C this century.

Assuming all net-zero plans are kept and implemented in full, that falls to 2.2C.

The Paris Agreement, the bedrock accord that aims to chart humanity's path away from catastrophic heating, commits nations to limit temperatures to "well below" 2C and to work towards a safer 1.5-C cap.

This week saw several new announcements, including India vowing to be net-zero by 2070 and an international agreement to cut 30 per cent of global methane emissions by 2030.

Read | What is Net Zero? Can India achieve it in 50 years?

Experts say these and other pledges could have a significant effect on temperature rises.

Fatih Birol, executive director of the International Energy Agency, on Thursday said that analysis by his organisation -- which has yet to be published -- showed that if all COP26 pledges were implemented it would limit heating to 1.8C.

He stressed however that the figure was heavily dependent on nations making the swift emissions cuts needed to implement net-zero plans.

"What is essential is for governments to turn their pledges into clear and credible policy actions and strategies today."

An assessment by the University of Melbourne this week analysed countries new net-zero pledges, including India and largest emitter China's and found that they represent Assessment from the University of Melbourne said there had been a "strong step forward" towards 1.5C.

The team ran the NDCs through the same climate model used on the Intergovernmental Panel on Climate Change's most recent report.

They found that the new promises -- again, if implemented, would warm Earth 1.9C by 2100.

UN Climate Change on Thursday issued a rapid assessment of the new NDCs.

Read | India, China missing from COP26 coal phase-out deal

While it has yet to convert the calculations to a temperature rise equivalent, it found that latest plans would see carbon emissions rise 13.7 per cent by 2030.

This compares with the 45 per cent drop in pollution needed for 1.5C.

It however said that for the 74 nations that have submitted detailed net-zero plans, emissions would be 70-79 per cent lower in 2050 compared with 2019 levels.

The UN Environment Programme said last month that only emissions cuts this decade that are eight times deeper than planned would keep temperatures to 1.5C.

UNEP director Inger Andersen told AFP that she welcomed the numbers circulating after the first week of COP26.

"But we don't do back on the envelope calculation, we do technical work," she told AFP.

"Obviously the more announcements that are out there the better it is, but these announcements have to be followed by action."

Juan Pablo Osornio, from Greenpeace, said that the only figure that really mattered was 1.5C.

"If we breach 1.5C then some countries will simply disappear from the map," he said.

"So the takeaway from these calculations is that we need to see not just words but action, and a lot more of it."

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