A for adaptation: Rising sea levels, increased droughts, floods and heatwaves, and changing seasonal weather patterns mean that countries will have to adapt to protect ordinary citizens, businesses and infrastructure such as transport, energy and water supply to prevent the worst effects of climate change having an impact on the economy. Adaptation is the term used to refer to such preparations and includes measures such as protecting coastal areas by building sea walls, reforestation to try to prevent flooding, increasing water conservation and changing crops to varieties that flourish in warmer climates.

Additionality
This is the proof required to show that offset projects under the UN-managed Clean Development Mechanism will in fact reduce carbon emissions.

Afforestation
The replanting of trees. About 20% of all global carbon dioxide emissions come from the destruction of forests. Preventing that is the main focus of the UN talks but China is also keen on creating new forests.

Annex countries
Under the UN Framework Convention on Climate Change, developed and developing nations are split, or "annexed" across three main groups with different commitments to emissions targets.

Annex I
There are currently 40 countries in annex I, plus the European commission, which include all Organisation for Economic Co-operation and Development (OECD) industrialised nations such as the US, UK, Germany, Japan and Russia.

Annex II
Countries are from the OECD members of annex I, but are also required to provide financial resources to enable developing countries to undertake emissions reduction activities under the convention and to help them adapt to adverse effects of climate change. In addition, they have to "take all practicable steps" to promote the development and transfer of environmentally friendly technologies to developing countries. Funding provided by Annex II parties is channelled mostly through the UNFCCC's financial mechanism.

Non-annex I parties
China and India, which since the Kyoto protocol was agreed in 1992 have emerged as economic powerhouses, head this list of developing countries. The group also includes much poorer countries that are most vulnerable to the effects of climate change such as Bangladesh, Haiti and Kenya.
Anthropogenic emissions
Carbon dioxide is naturally occurring in the atmosphere, but human activities such as using fossil fuels and farming cause additional greenhouse gases.

Cap and trade
One way of setting a limit on greenhouse gas emissions for a region or industry. Polluters are given carbon permits that add up to the cap. They can then sell permits if the have cut their emissions to those who have not. In theory, allows a market to deliver cuts efficiently.

Carbon dioxide equivalent (CO2e)
Carbon dioxide equivalent (CO2e) describes how much global warming a greenhouse gas may cause, using carbon dioxide as the base unit. Other gases with warming effects are methane, perfluorocarbons and nitrous oxide (laughing gas).

Conference of the Parties (COP)
COP is the supreme body of the UNFCCC which meets annually to review global climate change targets and commitments. COP 15: The official title of the 15th session of the COP signed up to the Kyoto agreement which is organised by the UNFCCC.

Carbon intensity
How much fossil fuels you have to burn to produce an economic unit. Reducing carbon intensity, as China has said it will, means GDP will continue to rise without carbon emissions rising at the same rate through greater energy efficiency and investment in greener technologies.

Carbon tax
A direct tax on activities that result in carbon emissions. Much less bureaucratic than cap-and-trade but cannot deliver an exact cut in overall emissions.

Implicit targets
A diplomatic phrase deployed by India to describe targets India has chosen for itself and for which it will not be held to account by anyone else.

Offsetting
Paying for reductions in emissions elsewhere to compensate for polluting activities. Popular on a voluntary basis for flights, but criticised on a national level for allowing rich nations to but their way out of making cuts at home.

Peak emissions
The time at which global greenhouse gas emissions stop growing and begin to fall. Scientists say that year must be 2015 if dangerous climate change is to be averted but current trends will not achieve this.