Paris –

The United Nations has been holding global climate summits, or COPs (Conference of the Parties), since 1995 as it tries to stabilize greenhouse gas emissions and prevent climate change.

Here are some of the standout gatherings:

1990: The beginnings

In 1990 UN climate experts reported that heat-trapping greenhouse gases generated by human activity are on the rise, and could intensify planetary warming.

Two years later, 150 leaders at the UN "Earth Summit" in Rio de Janeiro set up the UN Framework Convention on Climate Change (UNFCCC), with the aim of reducing greenhouse gas emissions.

The first COP met in Berlin in 1995, with vastly different priorities and concerns emerging.

2005: COP3, Kyoto Protocol

In 1997, nations agreed in Kyoto, Japan, on a landmark treaty setting a 2008-2012 timeframe for industrialized nations to reduce greenhouse gas emissions by an average 5.2 percent from 1990 levels.

In 2001, the world's then-leading carbon emitter, the United States, refused to ratify the protocol, which took effect in 2005 but failed to contain the explosion of emissions.

2009: COP15, Copenhagen catastrophe

COP15 in Copenhagen failed in December 2009 to achieve an agreement for the post-2012 period, amid bickering between rich and poor countries.

Several dozen major emitters, including China and the United States, reached a political goal of limiting global temperature increases to two degrees Celsius above pre-industrial levels but were vague regarding how the goal was to be reached.

2015: COP21, Paris accord

In 2015, around 195 country delegations signed up to the Paris Agreement to limit warming to "well below" 2 degrees Celsius above pre-industrial levels.

A more ambitious cap of 1.5 C was also adopted.

But the first global stocktake in 2023 of the accord affirmed that the world was not on track to limit global warming to 1.5 C and outlined bold actions for governments and stakeholders to urgently undertake.

2021: COP26 ends in tears

Under the chairmanship of Britain's Alok Sharma, nearly 200 countries pledged at COP26 in Glasgow in 2021 to speed up the fight against rising temperatures, after two weeks of marathon negotiations.

But India and China weakened the language of the final text to retain high-polluting coal, forcing tears and an exasperated apology from Sharma as he brought down the gavel.

2023: COP28, beginning of the end for coal

Nearly 200 countries at COP28 in Dubai in 2023 reached a landmark agreement stating that the world would be "transitioning away from fossil fuels" in order to achieve net-zero emissions by 2050.

It is the first time in the COP's history that all fossil fuels are explicitly mentioned in an accord.

The deal was greeted by applause and relief, but small island nations and other countries were more skeptical, as the agreement did not set any precise deadline and left plenty of room for maneuvre for hydrocarbon-producing countries.