By Adam Mynott BBC correspondent in Delhi

Climate change and its serious impact on economy and agriculture is at the centre of discussion at a 10-day UN conference in the Indian capital.

Key points of climate change deal

Finance - funding for poor countries to develop new technology Mechanisms - tough systems in each country to verify and report carbon emissions Sinks - heavily forested countries can use their 'tree sinks' to offset greenhouse gases Compliance - countries that fail to keep to their greenhouse gas reduction targets should face legally binding consequences

The governments of 185 countries are represented at the conference which began in Delhi on Wednesday.

They will be discussing the impact of climate change on agriculture, human health and the world economy before the Kyoto agreement comes into force next year.

At the end, a Delhi declaration will be signed, highlighting actions that need to be taken to halt what has been described as the biggest threat facing mankind - global warming.

Before a word has even been uttered at the conference, environmental groups have said that progress on cutting greenhouse gases will be blocked again by powerful interest groups in the fossil fuel industry.

No important decisions are expected at the Delhi conference.

But environmental activists have said developed countries which produce the majority of greenhouse gases will continue to run away from their responsibilities to find alternative energy sources by trading their greenhouse gas emission quotas with developing countries.

So-called carbon trading allows them to counteract their emission of carbon dioxide by investing in forestation and green energy projects in other countries.