By Fiona Harvey and Damian Carrington / The Guardian

Governments are falling badly behind on low-carbon energy, putting carbon reduction targets out of reach and pushing the world to the brink of catastrophic climate change, the world’s leading independent energy authority will warn on Wednesday.

The stark judgment is being given at a key meeting of energy ministers from the world’s biggest economies and emitters taking place in London on Wednesday – a meeting already overshadowed by David Cameron’s last-minute withdrawal from a keynote speech planned for Thursday.

“The world’s energy system is being pushed to breaking point,” Maria van der Hoeven, executive director of the International Energy Agency, writes in today’s Guardian. “Our addiction to fossil fuels grows stronger each year. Many clean energy technologies are available but they are not being deployed quickly enough to avert potentially disastrous consequences.”

On current form, she warns, the world is on track for warming of 6C by the end of the century – a level that would create catastrophe, wiping out agriculture in many areas and rendering swathes of the globe uninhabitable, as well as raising sea levels and causing mass migration, according to scientists.

Van der Hoeven, whose deputy will present the IEA’s findings to the Third Clean Energy Ministerial, put the blame squarely on policymakers, and challenged ministers to step up.

She said: “The current state of affairs is unacceptable precisely because we have a responsibility and a golden opportunity to act. Energy-related CO2 emissions are at historic highs, and under current policies, we estimate that energy use and CO2 emissions would increase by a third by 2020, and almost double by 2050. This would be likely to send global temperatures at least 6C higher within this century.”

The prime minister has caused controversy because a planned “keynote” speech for Thursday at the meeting – which would have been his first on green issues since being elected – has been scaled back to only a few introductory remarks at a round table meeting.

“The speech was a planned and much-anticipated major intervention, so his decision not to deliver it is a massive failure of leadership,” said David Nussbaum, chief executive of WWF-UK, the group that took Cameron on his famous “husky-hugging” trip to the Arctic in 2006. “Now, with his government’s approach to climate and energy policy in disarray, people are asking where the prime minister stands on these key issues.”

Energy experts speculated he was unwilling to make a long public appearance in front of the press during a what has been a torrid few weeks.

In its report, Tracking Clean Energy Progress, the IEA, widely regarded as the gold standard for energy research, ranked progress on 11 key low-carbon indicators, including renewables, nuclear energy and carbon capture and storage. It found the world was on track to meet just one of these targets.

Some technologies that governments have been relying on to reduce emissions – such as carbon capture and storage – were not even off the ground yet, despite years of development.

Read more from The Guardian: http://www.guardian.co.uk/environment/2012/apr/25/governments-catastrophic-climate-change-iea