The developing world was justified in raising its level of emissions while rich countries should commit to "ambitious" reductions, President Jacob Zuma said on Friday.

"As they justifiably pursue their own development paths, it is expected that developing countries' emissions will increase," Zuma said in a speech prepared for delivery at the United Nations Climate Change conference in Copenhagen.

"Our view remains that all developed countries must commit to ambitious, legally binding emission reduction targets."

"We need an agreement that recognises the common responsibility of all nations to reduce emissions, while not retarding the development of developing countries," Zuma said.

The UN Climate Change conference is seeking a resolution to reduce global emissions of greenhouse gases in an effort to slow and stop climate change. A frequent criticism made of plans to
reduce emissions is that it will hamper development.

Zuma said that while the wealthy, developed world was responsible for the bulk of current emissions, the effects of climate change would be felt by the developing world.

He said that South Africa was already being affected by climate change.

"Weather patterns in coastal provinces are already wreaking havoc on the lives of our people, which makes this challenge a reality that we are already confronting."

Despite asserting the developing world's right to economic growth, Zuma said that they still needed to commit to "relative" reductions in emissions.

"Developing countries should commit to nationally appropriate mitigation action, to achieve a decline in emissions relative to business as usual," he said.

"This would be conditional on finance, technology and capacity building support from developed countries."

Zuma said that with the assistance of wealthy countries, South Africa could reduce its emissions by 34 percent by 2020 and 42 percent by 2025.

US President Barrack Obama, also speaking on Friday, said the US, which is the second largest carbon emitter after China, had committed to "bold action".

He outlined a plan for combating climate change which would require all nations to reduce their emissions with the largest reductions from the developed world.

To assess this, he proposed an agency to monitor emissions. Obama promised that the US would pledge $10 billion for developing nations to adapt to reduced emissions and would campaign to organise a total $100 billion from around the world.

However, Obama warned that no nation could expect to come away from an agreement completely pleased.

"This is not a perfect agreement, and no country would get everything that it wants.

"There are those developing countries that want aid with no strings attached, and who think that the most advanced nations should pay a higher price," said Obama.

"There are those advanced nations who think that developing countries cannot absorb this assistance, or that the world's fastest-growing emitters should bear a greater share of the burden."

Obama said the world had been "imprisoned" by these divisions for years and must break free if climate change were to be tackled.