clipped from www.latimes.com

WASHINGTON -- The world pumped up emissions of the chief human-produced global warming gas last year, setting a course that could push beyond leading scientists' projected worst-case scenario, international researchers said Thursday.

The new numbers, which some scientists called "scary," were a surprise because experts thought an economic downturn would slow energy use. Instead, carbon dioxide output rose 3% from 2006 to 2007.

That amount exceeds the most dire outlook for emissions from burning coal and oil and related activities as projected by a Nobel Prize-winning group of international scientists in 2007.

The U.N.'s Intergovernmental Panel on Climate Change has warned that an increase of between 3.2 and 9.7 degrees Fahrenheit could trigger massive environmental changes, including melting of the Greenland ice sheet, the Himalayan-Tibetan glaciers and summer sea ice in the Arctic.