This year’s UN climate conference in Baku, Azerbaijan, marks the 29th gathering of world leaders to combat global warming since the first “Conference of the Parties” in 1995.

Here are some of the most notable moments in the history of climate negotiations:

1800s – For approximately 6,000 years before the industrial age, global levels of atmospheric carbon dioxide (CO2) remained around 280 parts per million (“ppm”). Several European scientists began to study how different gases trap heat, and in the 1890s Svante Arrhenius of Sweden calculated the effect on temperature of doubling atmospheric CO2 levels, demonstrating how burning fossil fuels would warm the world. planet.

1938 – British engineer Guy Callendar determines that global temperatures are rising along with rising CO2 levels and hypothesizes that the two are linked.

1958 – American scientist Charles David Keeling begins measuring CO2 levels above Hawaii’s Mauna Loa Observatory, resulting in the “Keeling Curve” graph which shows rising CO2 concentrations.

1990 – At the second UN World Climate Conference, scientists highlight the risks of global warming for nature and society. British Prime Minister Margaret Thatcher calls for binding emissions targets.

1992 – Countries attending the Rio Earth Summit sign the United Nations Framework Convention on Climate Change (UNFCCC). The treaty establishes the idea of ​​”common but differentiated responsibilities”, meaning that developed countries must do more to combat emissions linked to global warming, because they have historically emitted the most.

1995 – UNFCCC signatories hold the first “conference of the parties,” or COP, in Berlin, with the final document calling for legally binding emissions targets.

1997 – At COP3 in Kyoto, Japan, parties agree on various emissions reductions for each of the developed countries. In the United States, Senate Republicans denounce the Kyoto Protocol as “dead on arrival.”

2000 – After losing the US presidential election, Al Gore begins giving lectures around the world on climate science and policy which are eventually made into the 2006 documentary An Inconvenient Truth. The film won an Oscar, while Gore and the UN’s climate science authority – the Intergovernmental Panel on Climate Change – received the Nobel Peace Prize.

2001 – US President George W. Bush calls the Kyoto Protocol “fatally flawed”, signaling the country’s effective exit.

2005 – The Kyoto Protocol comes into force after Russia ratifies it, meeting the requirement of ratification by at least 55 countries accounting for at least 55% of emissions.

2009 – COP15 negotiations in Copenhagen are on the verge of collapse after rows over the post-Kyoto framework, with countries voting to “take note” of a non-binding political declaration.

2010 – COP16 in Cancun fails to set new binding emissions targets, but the Cancun Accords establish a Green Climate Fund to help developing countries reduce their emissions and adapt to climate change conditions. a warmer world.

2011 – COP17 negotiations in Durban, South Africa, fail after China, the United States and India refused to reduce their emissions before 2015. Delegates instead extended the Kyoto Protocol until 2017.

2012 – As Russia, Japan and New Zealand oppose new emissions targets that do not extend to developing countries, countries meeting at COP18 in Doha extend the Kyoto Protocol until in 2020.

2013 – Atmospheric CO2 levels exceed 400 ppm for the first time in recorded history.

2015 – The global average temperature exceeds the pre-industrial average by 1 degree Celsius. COP21 negotiations result in the Paris Agreement, the first pact to call for increasingly ambitious emissions commitments from developed and developing countries. Delegates also pledge to try to keep warming to 1.5°C (2.7 Fahrenheit).

2017 – US President Donald Trump commits to withdrawing the United States from the Paris Treaty, which will occur in 2020.

2018 – Young activist Greta Thunberg gains worldwide attention by protesting in front of the Swedish parliament and, over time, rallies young people to join weekly climate protests around the world.

2020 – The annual COP is postponed due to the COVID-19 pandemic.

2021 – Newly elected US President Joe Biden rejoins the Paris Agreement. Later, at COP26, the Glasgow Pact sets the goal of using less coal and defines certain rules for trading carbon credits to offset emissions.

2022 – The Intergovernmental Panel on Climate Change warns that the world faces a risk of catastrophic and irreversible climate change. Later that year, COP27 in Sharm el-Sheikh, Egypt, agreed to create a fund for losses and damages from costly climate disasters, but did little to address the emissions that fuel those disasters. .

2023 – At COP28 in the oil-producing United Arab Emirates, countries agree to abandon the use of fossil fuels. REUTERS