The bloc will unveil plans for a landmark climate law this week - but environment groups say it will lead to a decade of delay

(Updates with draft law document, adds post-2050 goal)

By Kate Abnett

BRUSSELS, March 2 (Reuters) - Environmental groups said on Monday that a decade could be lost in Brussels' plan to combat change because its planned "climate law", which could tighten emission targets for member states every five years, would not kick in until 2030.

The European Commission will propose a regulation on Wednesday containing its "Green Deal" plan for the European Union to reduce its net greenhouse gas emissions to zero by 2050.

According to a draft seen by Reuters, it would give the bloc's executive power to set new interim targets for EU countries every five years, starting from 2030.

Environmental groups said the plan to make the EU's long-term climate goal legally binding was a step in the right direction, but that 2035 was too late as the first date when new interim targets could be set.

"The elephant in the room will continue to be the 2030 target ... what we do from now until 2030 will determine whether we meet the 1.5 degree target," Greenpeace climate policy adviser Sebastian Mang said.

"That is the test – what we do until 2030 is the most important," he told Reuters.

A Commission spokeswoman declined to comment on the proposal - which will need the approval of member states and the European Parliament - before it is unveiled on Wednesday.

The United Nations says global greenhouse gas emissions must fall by an average of 7.6% each year from now until 2030 to limit global warming to 1.5 degrees Celsius (2.7 Fahrenheit) - the level that scientists say would avoid the most catastrophic impacts of climate change.

"This year, what is really on the table is 2030 ... and this target is not included in this review mechanism," Climate Action Network policy coordinator Klaus Roehrig told Reuters.

The European Commission wants to toughen the EU's 2030 climate target this year, to mandate a 50% or 55% cut in greenhouse gas emissions from 1990 levels, rather than the current minimum of 40%.

The bloc needs to revise its 2030 goal before the U.N. climate summit in November, where all parties to the Paris Agreement on climate change must increase their commitments to curb their emissions.

All EU countries except Poland have agreed to the EU's target of net zero emissions by 2050. But some states say a tougher 2030 goal is unrealistic, given the technological and economic overhaul that would be needed to drive bigger cuts in the next decade.

The draft EU climate law says the bloc should not only reach "net zero" emissions by 2050, but aim to achieve net "removals" of greenhouse gases after this date. Since greenhouse gases can remain in the atmosphere for years, this would help curb the cumulative impact of emissions produced before 2050, it says. (Editing by John Chalmers, Kevin Liffey and Andrew Heavens)

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