BRUSSELS, Belgium (AP) -- Unilateral sanctions against major polluters by countries applying stricter environmental standards would create serious political problems, the chief U.N. climate scientist warned Wednesday.

Rajendra Pachauri, chair of the U.N. Intergovernmental Panel on Climate Change, which shared last year's Nobel Peace Prize with former U.S. Vice President Al Gore, said applying import tariffs on goods from countries that do not comply with low carbon technologies needs to be avoided.

''This issue would be politically very divisive, you'd create a lot of political problems if certain groups of countries were to take these actions,'' Pachauri told journalists at the European Parliament, where he met members of the assembly's group on climate change.

Pachauri responded to a warning by the European Union that the United States, China and other major polluters could face consequences if they do not sign up to an international agreement on fighting global warming by next year.

The leaders of the EU's 27 member states said at a summit two weeks ago that the bloc could take ''appropriate measures'' against such countries. It did not specify the measures, but French President Nicolas Sarkozy said the EU should set a mechanism to allow it to ''strike against the imports from countries that don't play by the rules of the game on environmental protection.''

 

The EU pledged last year to cut carbon emissions by 20 percent from 1990 levels by 2020. It is hoping for similar commitments from other major economies at a conference in Copenhagen, Denmark, next year. Otherwise it says protection will be needed for European companies facing unfair competition from heavily polluting rivals in China or the United States -- the world's biggest emitters of carbon dioxide.

Pachauri said he hoped all countries will agree to adequate cuts to greenhouse gases in Copenhagen and no further unilateral action will be required.

''Hopefully we'll avoid the need for tariffs and sanctions on countries that don't comply with low carbon technology,'' he said.

Pachauri said delegates at this year's U.N. climate change conference, to be held in Poznan, Poland, should prepare the way for a deal in Copenhagen on a new climate treaty for the post-2012 period. He said there should be a clearer understanding after the meeting in Poznan of how deep global emission cuts will be.

The Pachauri-led climate change panel has warned of rising seas, droughts, and severe weather if the emissions of the industrial, transportation and agricultural gases blamed for warming are not sharply reduced.