By Bart H. Meijer

AMSTERDAM (Reuters) - Environmental activists took Royal Dutch Shell to court on Tuesday, demanding the energy firm drastically reduce the production of oil and gas to limit its effects on climate change.

Seven activist groups, including Greenpeace and Friends of the Earth, filed the lawsuit in the Netherlands in April last year on behalf of more than 17,000 Dutch citizens who say the oil major is threatening human rights as it continues to invest billions in the production of fossil fuels.

They are demanding that Shell cuts its greenhouse gas emissions almost in half by 2030 and to zero by 2050 - which would effectively force the Anglo-Dutch firm to quickly move away from oil and gas and direct its investment to sustainable sources of energy.

Shell has repeatedly said it agreed that action to fight climate change was needed, but that this court case would not help.

"No company can change the energy system by itself," Shell's lawyer, Dennis Horeman, said in court.

"All countries where Shell operates are determining policies to shape the energy transition. Shell will have to adjust its priorities and investments to those policies."

The plaintiffs say Shell is fully aware of the detrimental effects fossil fuels have on climate change.

"Shell's policies put it on a collision course with international climate agreements," the groups' lawyer, Roger Cox, said in his opening statement at the court.

"It is extremely dangerous and puts a brake on any action individual countries might be willing to take."

Shell has ramped up investment in biofuels, hydrogen and wind power in recent years and has promised to reduce the carbon intensity of the energy products it sells by 30% by 2035, compared with 2016 levels, as it aims for "net-zero emissions" by 2050.

But the green groups demand at least a 45% reduction of Shell's total emissions by 2030, relative to the pollution caused in 2019, as a step towards carbon-neutral production two decades later.

They feel strengthened by the so-called "Urgenda" case, in which the Dutch High Court last year ordered its government to step up the fight against climate change, as it said a lack of action was putting Dutch citizens in danger.

But Shell said that even though it supported international agreements to combat climate change, companies were not parties to these and cannot be held responsible in the same way as governments.

The district court of The Hague, where Shell is headquartered, has planned four days of hearings in the case in December.