* Poland strongest opponent to low carbon ambition
* EU needs to be united to send strong signal
* Negotiations very tough
By Barbara Lewis
BRUSSELS, March 9 Denmark led tough talks on Friday to try to persuade Poland not to block efforts to push European Union environmental policy beyond existing targets that only reach to 2020.
Coal-reliant Poland, worried about possible economic damage from deeper carbon cuts beyond the EU's existing goal of a 20 percent emissions reduction by 2020, has said it cannot yet support increased green policy ambition.
Denmark, current holder of the rotating EU presidency, which has set environmental progress at the heart of its leadership, said it was too soon to predict the outcome of Friday's talks, but it would be difficult to get a deal.
"As you all can hear and see in the press, it's going to be pretty tough negotiations, and I expect it to be a long day around the table," Denmark's Climate and Energy Minister Martin Lidegaard told reporters.
"But I have also talked to almost all the countries in bilateral meetings in the last days, and I know that we are all eager to try to get a result, although it's going to be quite difficult."
Presidency sources said Poland was isolated and weaker opposition from Romania and the Czech Republic could be deflected if the text was altered to underline that milestones are only indicative, not firm targets.
The Commission, with backing from the business community, has said there is an urgent need to clarify future policy direction to enable low carbon investment.
So far it has a set of roadmaps, which lay out a possible route towards a long-term target of reducing the bloc's carbon emissions by 80 percent by the middle of the century, to try to stave off catastrophic global warming.
Poland's Environment Minister Marcin Korolec this week wrote to his fellow EU environment ministers laying out his opposition to an increase in the EU's low carbon ambitions.
Government sources in Poland had predicted he would veto Friday's council conclusions.
The text of an environmental council meeting does not have firm policy status within the EU's complex decision-making process, but failure to get consensus would send a negative signal.
"The strength of the EU is when we stand united, we stand strong," Lidegaard said.
In June last year, Poland blocked environment council conclusions because they mentioned a milestone of a 25 percent emissions cut for 2020. Poland was the only one of the 27 EU member states to object.
To try to persuade it to sign up this time, Denmark dropped the 25 percent milestone, but draft council conclusions still referred to a 40 percent reduction by 2030, a 60 percent cut by 2040 and an 80 percent cut by 2050.
Whereas Poland opposes increased ambition, other EU nations have objected to what they see as a step in the wrong direction, with the dropping of the 25 percent milestone for 2020.
Environmental groups, which have written to the Polish government urging it not to block progress, have argued Poland risks being isolated not just in the EU, but also being cut off from domestic public opinion.
Representing non-governmental organisations Wendel Trio, director at Climate Action Network Europe, said he feared the most likely outcome on Friday was that Poland would prevent consensus being achieved.
What was at stake, he said, was "the inability of the EU to recognise what is happening in the world and to move forward".
The Commission, the EU's executive arm, can in theory continue preparing future policy, but any firm legislative proposals would need then to secure the backing of member states. (Additional reporting by Charlie Dunmore and Francesco Guarascio; Editing by Rex Merrifield and Erica Billingham)