LONDON — The world is likely to experience its warmest recorded year in 2007 because of the effects of the El Niño weather pattern and global warming, the British government’s weather forecasting division said.

There is a 60% chance that this year will be hotter than 1998, the current warmest year, the Met Office, based in Exeter, southwest England, said in a statement posted yesterday on its Web site. The main factor behind the prediction is the onset last year of El Niño, a warming of the eastern Pacific’s equatorial waters that occurs every two to seven years.

“The most important factor that determines one year relative to the next is El Niño, which started in the middle of 2006,” a climate research scientist at the Met Office, David Parker, said in a telephone interview from Godalming, southern England. “The forecast also takes into account the increase in the amount of greenhouse gases from human activities.”

The forecast reinforces the need for world leaders to act to stem emissions of gases such as carbon dioxide that many scientists say cause global warming, the head of the climate change program at WWF UK, Keith Allott, said in a telephone interview.

“It’s another important addition to the ever-increasing body of evidence that climate change is real, it’s happening now, and it’s getting worse,” Mr. Allott said. “This year is a critical year for world leaders to deliver momentum for the next phase of the Kyoto Protocol,” a treaty which sets emissions targets that end in 2012. WWF, an environmental charity, is known as the World Wildlife Fund in America.

This year, the Intergovernmental Panel on Climate Change, a body set up by the United Nations in 1988, will publish its fourth assessment on changing weather patterns, and the first since 2001. The report’s authors will examine evidence from thousands of scientists around the world.

Worldwide, the 10 warmest years since 1850 all occurred in the past 12 years.