Young climate activists in Germany announced Wednesday that they are seeking to join a lawsuit before the country’s top court that aims to force the government to do more to combat global warming.

The activists are backed by environmental groups such as Greenpeace, who say Germany’s current plan to reduce greenhouse gas emissions by 55% over the next decade isn’t good enough.

Miriam Siebeck, a 15-year-old student from Stuttgart, accused the government of passing “an absolutely ridiculous little climate package” last year that doesn’t allay the fears her generation has about the future.