A U.N. flag is pictured on the top of the WMO building with the Mont-Blanc massif in the background in Geneva
There has been no reverse in the trend of global warming and there is still consistent evidence for man-made climate change, the head of the U.N. World Meteorological Organisation (WMO) said on Monday.
A slow-down in the average pace of warming at the planet's surface this century has been cited by "climate skeptics" as evidence that climate change is not happening at the potentially catastrophic rate predicted by a U.N. panel of scientists.
But U.N. weather agency chief Michel Jarraud said ocean temperatures, in particular, were rising fast, and extreme weather events, forecast by climate scientists, showed climate change was inevitable for the coming centuries.
"There is no standstill in global warming," Jarraud said as he presented the WMO's annual review of the world's climate which concluded that 2013 tied with 2007 as the sixth hottest year since 1850 when recording of annual figures began.
"The warming of our oceans has accelerated, and at lower depths. More than 90 percent of the excess energy trapped by greenhouse gases is stored in the oceans.
"Levels of these greenhouse gases are at a record, meaning that our atmosphere and oceans will continue to warm for centuries to come. The laws of physics are non-negotiable," Jarraud told a news conference.
The 21-page survey said the global land and sea surface temperature in 2013 was 14.5 degrees Celsius (58.1 Fahrenheit), or 0.50C (0.90F) above the 1961-90 average. It was also 0.03C (0.05F) up on the average for 2001-2010.
The WMO's Annual Statement on the Status of the Climate, pointed to droughts, heatwaves, rising seas, floods and tropical cyclones around the globe last year as evidence of what the future might hold.
It was issued on the eve of a conference bringing climate scientists together with officials from over 100 governments in Japan from March 25-29 to approve a report on the effects of future global warming and how these might be mitigated.
A draft of this report, from the Intergovernmental Panel on Climate Change (IPCC), says global warming will disrupt food supplies, slow world economic growth and may already be causing irreversible damage to nature.
The chair of the IPCC, Rajendra Pachauri, told Reuters last week that the report made even more compelling the scientific arguments for a reduction in greenhouse gas emissions.
Some 200 countries have agreed to try to limit global warming to less than 2.0 degrees Celsius above pre-industrial times, largely by cutting emissions from burning fossil fuels like coal, oil and gas.
Skeptics argue that changes in global weather are the product of natural fluctuations or other natural causes.
But such arguments were rejected by Jarraud.
Natural phenomena like volcanoes or the El Nino/La Nina weather patterns originating in Pacific Ocean temperature changes had always framed the planet's climate, affecting heat levels and disasters like drought and floods, he said.
"But many of the extreme events of 2013 were consistent with what we would expect as a result of human-induced climate change," declared the WMO chief, pointing to the destruction wreaked by Typhoon Haiyan in the Philippines.
Another example was the record hot summer of 2012-13 in Australia which brought huge bush fires and destruction of property. Computer simulations showed the heat wave was 5 times as likely under human influence on climate, Jarraud said.
Among other extreme events of 2013 probably due to climate change were winter freezes in the U.S. south-east and Europe, heavy rains and floods in north-east China and eastern Russia, snow across the Middle East and drought in south-east Africa.