A new United Nations report by some of the world's top scientists says global warming is "very likely" man-made and that the world can expect higher temperatures, rising sea levels, and erratic weather.

The Intergovernmental Panel on Climate Change will formally release its report Friday in Paris, where experts from more than 100 nations have been meeting.

The panel defines the term "very likely" as meaning there is a 90 percent chance that man-made pollutants are causing the Earth to warm up.

A draft of the report forecasts global temperatures rising up to four degrees Celsius by the end of the century.

Some scientists believe natural weather patterns may be causing climate change and say the future will not be as dire as some experts predict.