Greenpeace together with German groups BUND and Deutsche Umwelthilfe filed the legal actions, which are also backed by Luisa Neubauer, a prominent activist of the Fridays for Future climate strike movement.
A dozen Bangladeshis and Nepalis, whose countries have been hard hit by global warming, also support the initiative.
“Climate protection is the protection of fundamental rights, particularly those of younger generations and inhabitants of most affected countries,” said Remo Klinger, a lawyer for the plaintiffs.
Germany should “make a contribution commensurate with its responsibility in terms of climate change”, added Klinger, urging the Federal Constitutional Court to “show the way to go”.
The environmental groups had already backed three farmer families who took their case to a Berlin administrative court last year, but that case was struck down by the judge.
Undeterred, they have now turned to Germany's highest court, evoking a decision of the Dutch supreme court, which in 2019 ordered the Dutch state to cut its greenhouse gas emissions.
Merkel's government last year agreed on a sweeping package of climate policy reforms that are estimated to cost 100 billion euros by 2030.
With plans to make train travel cheaper and air travel more costly, the package is intended to help Europe's largest economy slash its greenhouse gas emissions by 55 percent by 2030 compared to 1990 levels.
Environmental issues divide Germany
But climate activists argue that the plan is too weak to halt the planet from hurtling towards irreversible and devastating warming.
“It's not just about future generations, but also our generation and our lives,” said Neubauer.
After two blistering summers and the escalating Fridays for Future protests started by Swedish teenager Greta Thunberg, climate has shot up to the top of Germany's political agenda.
In her New Year's address, Merkel addressed the environmental challenge.
“Global warming and the crises that arise from it are caused by human activity. This means that we must do everything humanly possible to meet this human challenge,” she said.
The issue has also exposed a deep rift in Germany.
Tens of thousands of workers here are dependent on the vital car industry, and where coal mining is still a key employer in many parts of eastern states.
This gulf also runs through industries, such as in the agriculture sector.
While some farmers have taken their tractors to Berlin in protest against more stringent restrictions against pollutants or pesticides like glyphosate, others in the agricultural industry are holding counter-demonstrations against Berlin for not going further with outright bans on health-hazardous fertilizers.
In the latest action Wednesday, beekeepers dumped glyphosate-tainted honey at the entrance of the agriculture ministry.