The final deal pledged to make energy more accessible to the poor but there were no time-bound targets forcing countries to switch away from the fossil fuels blamed for heating up the planet to cleaner energy such as solar or wind.

Here are some key facts about energy:

ACCESS: About two billion people, a third of the world's population, lack access to modern energy sources, including electricity or even fossil fuels.

They rely on firewood or biomass - crop residues or animal dung - for cooking, heating and lighting. About 2.5 million women and children die every year from respiratory diseases caused by primitive cooking stoves.

Many people in developing nations, especially women, spend long hours searching for firewood, reducing their chances of education and development. As the population swells, rising demand for firewood leads to deforestation.

CONSUMPTION: Fossil fuels such as coal, oil and gas, are a major source of pollution and are blamed for global warming. They account for about 80 percent of total global energy consumption, down from 86 percent in 1971.

Nuclear energy accounts for about seven percent while hydropower, other renewables and fuels like firewood account for about 13 percent.

Per capita energy use is highest in developed nations where each person consumed the equivalent of 6.4 tonnes of oil per year in 1999, 10 times as much as in developing countries. The United States is the top consumer.

About 4.5 percent of the world's energy comes from modern renewable sources, up from 3.2 percent in 1971. Hydropower is the biggest such source, but large-scale schemes like dams are often controversial.

Modern biomass - burning firewood and other fuels in developing nations in more efficient cookers - and geothermal systems are seen by some as the best hope for reducing smoke-related diseases in the short term.

Wind and solar power have a big potential for growth but account for just 0.02 percent of total energy supply.

POLLUTION: Carbon dioxide from the burning of fossil fuels accounts for 75 percent of the gases blamed for global warming.

These "greenhouse gases" are linked to climate change which leads to more storms, floods and rising ocean levels.

Many nations have signed the Kyoto Protocol to cut such gas emissions, but the United States has pulled out of the pact.

Washington argues Kyoto will be too expensive for the U.S. economy and unfairly avoids setting emissions targets for fast growing developing nations such as China and India.

South African President Thabo Mbeki said if the Chinese consumed as much oil per person as U.S. citizens, China's oil consumption would surge to 80 million barrels per day, outstripping current world production of 74 million barrels.