Following is a chronology on climate change ahead of the 1-12 December conference of the United Nations Framework Convention on Climate Change (UNFCCC), in Poznan, Poland.

1827: French scientist Jean-Baptiste Fourier is the first to consider the "greenhouse effect", the phenomenon whereby atmospheric gases trap solar energy, increasing Earth's surface temperature.

1896: Swedish chemist Svante Arrhenius blames the burning of fossil fuels (oil, gas and coal) for producing carbon dioxide (CO2), the most polluting of the greenhouse gasses today blamed for climate change.

1988: The United Nations sets up a scientific authority to vet the evidence on global warming, the Intergovernmental Panel on Climate Change (IPCC).

1990: First IPCC report says levels of man-made greenhouse gases are increasing in the atmosphere and predicts these will cause global warming.

1992: Creation of the UNFCCC at the Rio Summit. The UNFCCC now has 192 member countries.

1997: UNFCCC members sign the Kyoto Protocol. Under its first phase, industrialised countries must cut emissions of six greenhouse gases so they are 5.2 percent lower than 1990 levels by the end of 2012.

2001: The Kyoto Protocol, still in framework form, is nearly wrecked after it is abandoned by the United States, then the world's biggest carbon emitter. President George W. Bush calls the treaty too expensive for the US and unfair as developing countries escape binding caps on their emissions. Kyoto is saved by the European Union (EU), which pilots an agreement on its rulebook and mechanisms, opening the way to ratification.

2005: Kyoto Protocol takes effect on 16 February.

2007: Landmark report by the IPCC delivers crippling blow to climate sceptics. It says the evidence for global warming is "unequivocal" and forecasts warming of 1.8-4.0°C by 2100 and an unquantifiable rise in sea levels.

Nobel Peace Prize awarded to IPCC and former US vice president Al Gore, whose documentary "An Inconvenient Truth" raised climate change awareness.

UNFCCC members including the US agree after marathon talks in Bali, Indonesia, to agree to a new treaty in Copenhagen by the end of 2009 that will succeed Kyoto.

2008: September — A consortium of scientific researchers, the Global Carbon Project (GCP), says greenhouse gas emissions have scaled new peaks, reports that China has leapfrogged the United States as the world's biggest carbon emitter and India is heading for third place.

November — Barack Obama is elected president of the United States; pledges to reverse Bush's climate policy. Sees goal of reducing US emissions to 1990 levels by 2020 and by 80 percent by 2050, using a cap-and-trade system and a 10-year programme worth $150-billion in renewable energy research and deployment.

December 1-12 — UNFCCC parties meet in Poznan, Poland, to hammer out negotiation blueprint in the run-up to the December 2009 deadline.

AFP