The U.N. Climate Change Secretariat released the news two weeks before it holds its next conference in Poland to review progress in setting new international goals for reducing emissions.
"The increase in emissions continues to be a cause of concern," top U.N. climate official Yvo de Boer told reporters.
"The data underscore the urgent need for action," he said.
But the U.N. report was not all bad news, saying that while emissions had risen over the past six years, they were still down 5 percent from 1990 levels - a drop attributed mostly to earlier economic decline in former communist eastern European countries.
Since 2000, however, these "economies in transition" have posted the highest emissions increases, with 7.4 percent more in 2006, Boer said.
The Bonn-based U.N. secretariat hopes a new agreement can be reached next year to replace the 1997 Kyoto Protocol, which required 37 industrialized nations to reduce greenhouse gas emissions an average of 5 percent below 1990 levels by 2012.
Those countries have lowered emissions by about 17 percent since 1990, but also posted a rise after 2000 - with just 16 nations on target to reach their Kyoto obligations. The U.N. report said 20 countries were lagging, and information on other countries was incomplete.
Experts say a new deal should be signed at the 2009 climate conference in Copenhagen, Denmark, so it can be ratified in time to replace the Kyoto Protocol when it expires in 2012.
Discussions at the Dec. 1-12 climate conference in Poznan, Poland, will be based on a 2007 accord reached in Bali, Indonesia, when the United States, India and China indicated they would participate.
De Boer (left) said he did not expect U.S. President-elect Barack Obama to send a representative to Poznan, but assured the U.S. delegation would not be dismissed as a "lame duck" group.
"I expect them to participate fully in the negotiations," de Boer said.
Total Aggregate Greenhouse Gas Emissions, 1990-2006 (in %)
Seventeen countries whose emissions increased more than 1% are in bold.
Czech Republic* -23.9%
European Community -4.6%
New Zealand 33%
Russian Federation* -29.3%
United Kingdom -15.6%
United States 14%
Base years differ for Bulgaria (1988), Hungary (1985-1987), Poland (1988), Romania (1989) and Slovenia (1986).
* Indicates countries transitioning to a market economy.
** Special consideration for Turkey, which is in early stages of industrialization; had not submitted complete data in time for report.