Q: What are the talks in Bonn?

A: They are the latest meeting of parties to the 1997 Kyoto Protocol, the international agreement on tackling climate change.

The Bonn negotiations are the seventh meeting since the protocol. The purpose of the meetings is to thrash out the small print so the treaty itself can be ratified and actually become law.

Q: What was Kyoto?

A: At the Japanese city of Kyoto in 1997, the world agreed that industrialised countries would take the lead in cutting emissions of carbon dioxide and other gases. By 2010, they were to reduce them to below 1990 levels.

To help them achieve their targets, there are several 'flexible mechanisms' that enable rich countries to escape having to fully meet this obligation - provided they pay for it.

Q: What are 'flexible mechanisms'?

A: Emissions trading is one mechanism, and it allows rich countries to 'buy' credits from poorer ones. For example, they could pay for a poor country to build a renewable energy plant.

Carbon 'sinks' are another. Under this, countries are allowed to pollute more if they ensure there are more forests to absorb the carbon dioxide. …