COP27 in Egypt is set to kick off on Sunday (6 November), with world leaders coming together to discuss a deepening climate crisis.
New UK Prime Minister Rishi Sunak had said he would not be going to the summit, but u-turned on Wednesday (3 November) after pressure from across the political spectrum. Former PM Boris Johnson will also be attending, as the UK hands over the COP presidency to Egypt.
It comes after COP26 was held in Glasgow in 2021. While some progress was made, critics argued it did not go far enough to keep global warming below the 1.5C target.
One of the key agreements made at the Glasgow edition of the annual climate summit was that all countries would revise their emissions targets and present them at COP27 - something known as the ‘ratchet mechanism’.
But what does this term mean - and why is it important? Here’s everything you need to know.
What is a ‘ratchet mechanism’?
A ‘ratchet mechanism’ is an informal term used to describe the requirement that countries will revise and communicate their emission targets - known as nationally determined contributions (NDCs) - every five years as part of the Paris Climate Agreement.
The term comes from the idea that amendments to plans and promises to tackle climate change will increase in a progressive manner at every review. This means that countries will be expected to promise more action every five years in an effort to reduce global warming and the effects of climate change.
The requirement to revise and communicate their new plans every five years is set out in Article Four of the Agreement and was acknowledged by all parties who signed the legally-binding document.
Why are countries revising their environmental plans?
Upon the creation of the Paris Climate Agreement, it was expected that the aims and targets set out by countries would need to be adapted as time progressed. This is due to the ever-evolving nature of climate change and its effect on factors such as global warming and rising sea levels, with the acknowledgement that the 2015 plans would not be enough to curb this alone.
How did ratchet mechanism feature at COP26?
COP26 was postponed from 2020 due to Covid. It provided countries with the first deadline to communicate their updated plan, with most publishing at least their first version of an NDC at the event or soon afterwards.
The submitted plans, when combined, showed the world is currently on course for a 13.7% rise in CO2 - or equivalent - emissions by 2030. But for 74 COP members setting out longer-term plans to tackle their emissions, their output is set to fall by 5.2% by 2030 and 70% to 79% by 2050 (compared to a 2010 benchmark).
Current UK plans, as set out at COP26, show the country aims to reduce its overall emissions by 52% compared to 2010 levels.
While it might sound like things are heading in the right direction, these current NDCs are not going to limit global heating to 1.5C, or even 2C. To keep temperatures capped at these levels would require emissions reductions of 45% or 25% respectively by 2030.
Also, with the energy crisis forcing countries to return to carbon-intensive fuels like coal, emissions could be heading even further in the wrong direction.
While activists want further revisions to NDCs to be published at COP27 in Egypt, developments are expected to be unlikely. The next set of official revisions are not due until 2026.