HARDEV SANOTRA

Copenhagen summit: There are 190-odd nations represented at the climate talks that started this week, but arguably only two that matter: the

President Barack Obama has been armed with new ammunition for the Copenhagen summit on climate change with an announcement yesterday giving the US administration enhanced authority to regulate carbon dioxide emissions.

The European Union withdrew an offer to increase its greenhouse gas emissions reduction target on Monday because it said similar offers made by many nations in the past month were inadequate to prevent significant climate change.

The largest and most important UN climate change conference in history opened Monday, with organisers warning diplomats from 192 nations that this could be the last best chance for a deal to protect the world from calamitous global warming.

As the biggest environmental meeting in history opens in Copenhagen, the scientific case for a global agreement to fight man-made climate change remains overwhelming.

Business leaders have called for agreement at Copenhagen, urging governments to provide the support for the vast investment in clean energy they say will be needed to sustain fuel supplies while curbing carbon dioxide emissions.

FT Energy Source is posting a daily question for our panel of expert commentators. Below, guest panellists Mindy Lubber of CERES, Robert Stavins of Harvard University, Jeremy Leggett of Solar Century and Julian Morris of the Policy Network respond to today

When Barack Obama, US president, decided late last week to attend the final stages of the fortnight-long United Nations climate change conference in Copenhagen, which begins on Monday, the gasp of relief from delegates heading to the Danish capital was almost audible.

The world is "within closing distance" of agreeing cuts in greenhouse gases that would satisfy scientific demands, according to a new analysis.

Officials from the governments of more than 190 countries arrived at the talks yesterday with the aim of forging a new global deal on climate change.