* Poland has received billions of euros from carbon trade
* Diplomats say Poland should not isolate itself
* Poland says considering legal challenges to agreed law
* For a Reuters graphic on Polish carbon market:
By Agnieszka Barteczko and Barbara Lewis
WARSAW/BRUSSELS, Nov 9 (Reuters) - Poland's bid to block global efforts to slow climate change is likely to struggle to gain traction as it risks alienating European partners and as top emitters China and the United States dominate the international debate.
Ahead of U.N. talks in Paris on a new climate pact, Poland's president vetoed an amendment to the Kyoto protocol on greenhouse gas emissions, saying Warsaw needed more time to assess the economic impact, a gesture the newly elected government says is just the start.
It says it will oppose any attempt to tighten European Union climate regulations and has even threatened to start undoing agreed EU law to reform the carbon market that adds to the cost of burning fossil fuel.
Poland's economy depends on highly polluting coal and the country has long opposed EU initiatives to curb carbon emissions. The conservative Law and Justice (PiS) party, elected last month, has pledged to take an even tougher stance than the previous centrist government, which was staunchly pro-EU.
The EU agreed last year to cut greenhouse gases by at least 40 percent by 2030, pitting heavy industry against green business, but PiS leader Jaroslaw Kaczynski called last month for a renegotiation of that deal, saying Poland needed more coal-based power stations.
"There are decisions that seem sacred, but then, with the changing world, they are modified," said Piotr Naimski, PiS politician and a former deputy economy minister responsible for energy.
He has said that Poland needs special solutions because of its "unique" coal-based energy sector.
Diplomats, lawyers and analysts, however, say Warsaw has much to lose by being too radical.
Poland has raked in more than 26 billion euros ($28 bln) from free pollution allowances and carbon auction revenues over the 10 years since the EU Emissions Trading System (ETS) - on which permits to burn fossil fuels are bought and sold - was launched, according to Thomson Reuters Point Carbon data.
"We are realistic and we are aware that Poland as just one country will not have an impact on the Paris outcome," said Grzegorz Tobiszowski, a PiS member with particular responsibility for the coal sector.
"But we want to draw our partners' attention to the extraordinary situation of Poland's coal-based economy."
To reinforce the point, PiS wants coal industry trade unions to accompany the Polish delegation to the climate change talks in Paris, which start on Nov. 30.
EU sources say the president's veto is unlikely to have much impact, especially as Poland is locked into EU-wide legal commitments to cut greenhouse gases by 2020 and is on track to more than meet its requirements.
Given that the entire EU is responsible for less than 10 percent of global emissions, top polluters China and the United States are more significant in the Paris talks, the sources say.
The EU, to be heard, needs to be united and Poland could alienate traditional allies who do not wish to be seen as so radical, diplomats said.
"Poland is addressing its domestic audience. It is not in its interest to isolate itself diplomatically," one European diplomat said, speaking on condition of anonymity. "The Visegrad countries will not support it."
The Visegrad group includes the Czech Republic, Hungary and Slovakia, as well as Poland, and they often unite when negotiating within the European Union.
Those countries have helped Poland to win concessions, such as free EU pollution allowances, for its coal industry, a major employer and the source of nearly all Poland's energy.
Poland has long said it needed to avoid regulatory or energy costs that would damage its competitiveness.
"I wouldn't expect any significant changes in the Polish government's approach to the EU and international climate policy but what I do expect is a change in the language," Ilona Jedrasik, policy officer at environmental law group ClientEarth, said.
Warsaw plans to continue to block reforms to strengthen the ETS, which forces more than 11,000 power plants, factories and airlines in the EU to surrender one carbon permit for every tonne they emit.
EU sources, though, are sceptical Poland can succeed, for instance, in challenging the creation of a Market Stability Reserve, agreed by the EU this year to remove some of the surplus allowances that have depressed the ETS, although industry also seeks to challenge different aspects of the market in court.
Naimski has said Poland could even leave the ETS, but analysts say they do not see how it could without also leaving the EU, something even the Eurosceptic PiS does not want. ($1 = 0.9289 euros) (Editing by Susan Fenton)
Our Standards: The Thomson Reuters Trust Principles.