The planet's temperature is rising, and it's rising at an accelerated pace that most scientists say is due to manmade factors. As the climate changes, they predict it will lead to more dramatic weather and disasters - not just droughts, but storms, floods and spreading disease too.

• Climate change increases the risks of conflict and migration
• 200-250 million people could be displaced by climate-related disasters by 2050
• The world's poor - who are the most vulnerable - need help to adapt

Statistics from the International Disaster Database show a steep increase in weather-related disasters since the middle of the 20th century, and the number of people affected is also going up. The Intergovernmental Panel on Climate Change (IPCC) says the world can expect more heatwaves and droughts, heavier rains, stronger storms and rising sea levels due to global warming caused by emissions of greenhouse gases.

Africa, Latin America and parts of Asia - where the climate is already more extreme and arid regions are common - are likely to be most affected as rainfall declines and its timing becomes less predictable.

Large numbers of people could be forced to find new homes as their living environments are submerged, or food and water become scarce. One respected scientist has estimated that between 200 and 250 million people could be displaced by climate-related disasters by the middle of the century. And experts say diseases will spread to new places as the planet changes.

In 2007, the Nobel Peace Prize was awarded jointly to the IPCC and former U.S. Vice President Al Gore for their work in building up and spreading knowledge about climate change. This underlined growing concern about the potential impact of climate change on security. Experts warn that where tensions triggered by the environmental impacts of climate change add to existing stresses, the risk of violence increases.

There's intense debate and a wide range of competing ideas on how to tackle what could be the most important issue of our time. Many developing countries believe richer nations should make greater commitments to curb their carbon emissions, and provide more funding to help them adapt to climate change.

Around 190 countries have agreed to negotiate a new pact to replace or extend the Kyoto Protocol, which binds rich nations - except the United States - to cap emissions of greenhouse gases until 2012. The talks are due to be concluded by the end of 2009, though key negotiators now predict the Copenhagen meeting will not produce a full deal and negotiations may continue into 2010.

Aid agencies have woken up to the impact of climate change on their projects and the communities with which they work. Increasingly, they are helping local people reduce the risk of climate-related disasters, and calling for more international support to cope with the negative consequences of climate change.