* Climate agreement brings relief to fractious coalition

* Measures could be tightened in parliamentary upper house

* Greens, environmentalists say measures are too modest

* Package envisages carbon pricing, road tolls

German Environment Minister Svenja Schulze took to Twitter to announce the approval of the measures, which would be enshrined in a Climate Protection Law.

The approval is a relief for Merkel, whose right-left coalition has suffered regional elections losses and been riven by disputes over pension and tax reforms. The parties plan a review of their loveless marriage by the end of the year.

“Finally there are binding rules for climate protection – and that’s a good thing. I have fought for this for a long time and I am happy that it was approved today,” Schulze wrote on Twitter.

As Merkel and her ministers met at the chancellery, hundreds of Extinction Rebellion climate activists blocked a major bridge nearby on the third day of global protests designed to press governments to take more drastic action against global warming.

“We have brought a ‘plastic sea’ with us to show the pollution in our oceans,” said Clara Thompson, spokeswoman for Extinction Rebellion. “We also want to draw attention to the (United Nations) World Climate Report.”

U.N. climate scientists warned in a report last month that if emissions of greenhouse gases are not slashed the world must face a reality of cities vanishing under rising seas, rivers running dry and marine life collapsing.

Merkel, who has faced criticism that the measures were unambitious, vowed this week that the climate package would contain a mechanism to monitor compliance with emission limits set for individual sectors.

The mechanism will allow ministries to monitor which sectors are meeting emissions goals and adjust targets based on their progress. Some of the mechanisms could yet be modified or toughened up in the upper chamber of parliament.

The overall goal of the measures – priced at 54 billion euros – is to cut German greenhouse gas emissions to 55% of the 1990 level by 2030.

Activists and the ecologist Green party, which has a strong position in the upper chamber, have been outraged by plans to introduce a carbon dioxide price of 10 euros ($10.97) a tonne for transport and heating in buildings from 2021 and gradually increase it to 35 euros in 2025.

Economists and activists had hoped for a starting price of at least 40 euros and point to Switzerland where that price is about 90 euros for heating with fossil fuels.

The government also wants to raise car and air traffic taxes as well as increase a road toll for trucks from 2023. It also wants to extend subsidies for electric cars and broaden a charging network.

It also wants to revive onshore wind turbine construction after it declined due to bureaucracy and citizens’ opposition. Building up renewable energy capacity is paramount given plans to phase out both nuclear and coal power plants. (Reporting by Holger Hansen Writing by Joseph Nasr Editing by Kathrin Jones, Michelle Martin and Thomas Escritt)