Clock on climate change ticking: Kerry

As the Intergovernmental Panel on Climate Change (IPCC) drew a grim picture in its latest report on global warming, US Secretary of State John Kerry warned that "the clock is ticking" and asked countries to match the urgency of response with the scale of the science.

"The clock is ticking. The more we delay, the greater the threat. Let's make our political system wake up and let's make the world respond," Kerry said in a statement after the IPCC delivered its Fifth Assessment Report known as "WGII AR5".

"Read this report and you can't deny the reality: Unless we act dramatically and quickly, science tells us our climate and our way of life are literally in jeopardy. Denial of the science is malpractice," Kerry said.

"There are those who say we can't afford to act. But waiting is truly unaffordable. The costs of inaction are catastrophic," he added.

"We can already see the damage it's causing to our ecosystems, wildlife, glaciers, and countless other natural habitats. We can feel the impact of rising temperatures and sea level rise on vulnerable coastal areas.

"We know the security risks of water scarcity and flooding; widespread land and marine species extinction; and devastated crop yields in some of the poorest nations on earth," he said.

"No single country causes climate change, and no one country can stop it. But we need to match the urgency of our response with the scale of the science," Kerry said, adding that the US is meeting this challenge through President Barack Obama's Climate Action Plan.

"We are committed to reaching an ambitious agreement to reduce global greenhouse gas emissions with other countries in the United Nations Framework Convention on Climate Change," he said.