Kerry: Ignoring climate science puts 'kids, grandkids' at risk

 US Secretary of State John Kerry said Sunday that those who ignore climate science do so at a risk to future generations, as UN experts unveiled the final chapter of a landmark climate report, AFP reports.

"Those who choose to ignore or dispute the science so clearly laid out in this report do so at great risk for all of us and for our kids and grandkids," Kerry said.

The UN's Intergovernmental Panel on Climate Change (IPCC) said Sunday that time is running out to limit global warming to two degrees Celsius (3.6 degrees Fahrenheit), and that current trends in carbon emissions heralded disaster.

Crowning a landmark review, the climate experts warned that emissions of three key greenhouse gases were at their highest in more than 800,000 years.

Kerry said the report issued in Copenhagen was a fresh warning, "another canary in the coal mine".

"The longer we are stuck in a debate over ideology and politics, the more the costs of inaction grow and grow," he said.

The report -- the first overview by the Nobel-winning organization since 2007 -- comes ahead of UN talks in Lima next month to pave the way to a 2015 pact in Paris to limit warming to a safer two degrees Celsius.

But the negotiations have been hung up for years over which countries should shoulder the cost for reducing carbon emissions, derived mainly from oil, gas and coal -- the backbone of the world's energy supply today.

"The bottom line is that our planet is warming due to human actions, the damage is already visible, and the challenge requires ambitious, decisive and immediate action," Kerry said.

"We're seeing more and more extreme weather and climate events, whether it's storm surges, devastating heat waves, and torrential rain, across the globe," Kerry said. "It's not a coincidence."

Earth, the panel warned, is on a likely trajectory for at least four degrees Celsius warming by 2100 over pre-industrial times -- a recipe for worsening drought, flood, rising seas and species extinction.

The report said switching to cleaner sources, reducing energy efficiency and implementing other emission-mitigating measures would be far cheaper than the cost of climate damage.