The U.N. weather office says 2011 is currently the 10th hottest year on record and warned that greenhouse gas levels are nearing a critical point.

The World Meteorological Organization said in a statement Tuesday that this year's weather continues a string of warm temperatures, with 13 of the 15 hottest years since 1850 occurring since 1997.

The agency also said greenhouse gases in the atmosphere are “very rapidly” approaching levels that scientists say could trigger irreversible changes to the planet.

The report came on the second day of a global climate change conference in Durban, South Africa, where nearly 200 countries are trying to negotiate an agreement to address the issue.

Also Tuesday, Oxfam, the World Wildlife Fund and a major shipping industry group called on conference delegates to push for action in reducing shipping emissions.

The groups said in a joint statement that money raised from regulating shipping to lower carbon dioxide emissions could be used to fund climate change mitigation efforts in developing countries.

They say the money could be part of the Green Climate Fund, a $100 billion-a-year effort that is being considered at the conference in Durban.

Tim Gore, a climate change advisor for Oxfam, said Tuesday the groups understand the need to cut emissions.

Gore says it is important to focus on shipping because the effort has the backing of aid agencies and many governments, and that the groups hope the initiative can later serve as an example for the aviation industry.