* EU official says U.S. 2020 emissions goal not enough
* Says U.S. should not waste time considering a carbon tax
* Says EU will not intervene in falling carbon permit prices
(Adds comments on U.S. cap and trade plans, EU carbon price)
LONDON, March 6 (Reuters) - The United States must make deeper cuts in greenhouse gas emissions than proposed by President Barack Obama if the world is to stand a chance of avoiding devastating climate change, an EU official said.
Jos Delbeke, the European Commission's deputy director-general of the environment, said a goal of bringing U.S. greenhouse gas emissions back to 1990 levels by 2020, set by Obama last month, will probably not be enough.
"I doubt whether that will bring us to the average required by developed countries," he told Reuters on Friday. "We in Europe would hope the U.S. will do more than stabilisation of 1990 levels. I will not hide that."
Scientists say global emissions must stabilise by 2015, then fall by some 80 percent below 1990 levels by 2050 if the world is to keep temperatures from rising more than 2 degrees Celsius.
A rise of over 2 degrees may trigger widespread flooding, droughts, disease and famine, United Nations scientists said.
The 27-nation European Union has committed to reducing greenhouse gas emissions by 20 percent below 1990 levels by 2020, upping that target to 30 percent if a successor agreement to the Kyoto Protocol climate pact is signed.
"The EU's position is that developed countries, as a group, must cut 30 percent below 1990 levels by 2020," Delbeke told a clean energy conference held by analysts New Energy Finance.
With its carbon dioxide emissions rising nearly 20 percent since 1990, the United States is the most polluting developed country.
Stabilisation of U.S. emissions at 1990 levels in 2020 would make it near impossible for developed countries to reach the EU's 30 percent group target.
Delbeke said although the U.S. target falls short of what is required, he remains hopeful.
"This was an important first step ... I understand that this is just the opening of discussions and not their last word."
CARBON TRADING
The European Union has adopted a cap-and-trade approach, which involves setting a cap on emissions then allocating a corresponding number of carbon permits that participants can trade amongst each other.
Delbeke advised the United States against wasting time by considering different methods of putting a price on carbon dioxide, including the idea of a government-imposed carbon tax.
"Please do not lose time on the carbon tax debate," he said. "We lost almost a decade before we came to cap-and-trade, and if we would have started it earlier it would have been a major step forward."
Last week, Obama indicated he favoured cap-and-trade by including in his budget $646 billion in future revenues from permit auctions to be held between 2012-2019.
Europe launched its cap-and-trade scheme in 2005 but design flaws have caused carbon prices to fluctuate wildly.
In the latest market trend, cash-strapped firms in Europe began dumping 2008 permits late last year to raise short-term funds, with a view to borrowing from their 2009 quota.
As a result, EU carbon prices have plummeted some 75 percent from a 2-year high of 30 euros a tonne ($37.93) hit last July.
This has prompted some analysts to call for EU intervention, possibly by setting a minimum price floor, a reserve price for permit auctions, or reducing the permits issued in future years.
"We are reticent to go into price management ... The (emissions) cap that was agreed creates a stable regulatory environment," he said, referring to 2013-2020 EU climate targets agreed by member states in December. (Reporting by Michael Szabo; Editing by Anthony Barker)