The World Meteorological Organization (WMO), in its annual briefing to the UN climate summit, said that the Earth's surface continues to get warmer, and the warming is due to human activities.

According to the WMO, 2011 is so far the 10th warmest year on record and that the continued warming is being masked by the La Nina phenomenon which has a cooling effect.

The WMO briefing disappointed delegates to the UN climate summit who had hoped that the slowdown in temperature rise observed over the last decade meant global warming had stopped.

The WMO report noted that although provisional figures put 2011 as only the 10th warmest on record, still it has been hotter than any previous year that experienced strong La Nina conditions.

This year's La Nina conditions were also associated with droughts in East Africa, Pacific islands and the southern US, and flooding in southern Africa, eastern Australia and southern Asia, the WMO said.

The agency pointed out that the 13 warmest years on record have all occurred in the 15 years since 1997, and during the Arctic melt the sea ice declined to the smallest volume on record.

"Our science is solid, and it proves unequivocally that the world is warming and that this warming is due to human activities," said WMO secretary-general Michel Jarraud.

"Concentrations of greenhouse gases... are very rapidly approaching levels consistent with a 2.0-2.4C rise in average global temperatures, which scientists believe could trigger far-reaching and irreversible changes in our Earth, biosphere and oceans," said Jarraud.

The WMO cited some actions that can help cope with the effects of climate change such as construction of barriers to protect against rising sea levels, or conversion to crops that can survive high temperatures and drought.