"Climate change is dangerous and is happening now," Greenpeace lawyer Frank Peters said at a summary hearing at the district court of The Hague.

"The government has missed the chance to deal with pollution caused by aviation now."

After months of negotiations, the Dutch government in June agreed to offer KLM an aid package to keep it flying through the coronavirus crisis.

The bailout terms include new environmental and noise pollution targets for KLM which were insisted upon by the Dutch parliament, as well as cost cuts.

These order KLM to cut its greenhouse gas emissions per passenger in half by 2030 relative to their 2005 levels.

But Greenpeace said this will not reduce total emissions, as long as the number of passengers continues to grow.

"The state should take every opportunity to cut emissions", Peters said. "Delaying this will lead to a subsidised increase of emissions."

But the government said its conditions were in line with international aviation agreements, while stricter demands could easily bring down the airline it is trying to save.

"Stricter climate demands will mean significantly higher costs and a disadvantage to competitors", the state's lawyer Karlijn Teuben said.

"An order to stop the support straightaway will also hurt the company's ability to borrow money and it is difficult to see how this would not risk bankruptcy."

The court said it would decide on the demands made by Greenpeace by December 9 at the latest.

Dutch environmental groups have successfully challenged the government on climate goals in the past, notably in the "Urgenda" lawsuit which forced the government to follow through on promises to cut greenhouse emissions by 25% this year from 1990 levels.

KLM currently operates at around 40-50% of its normal capacity due to the coronavirus pandemic, and last month reported a loss of 1.7 billion euros for the first nine months of the year.

It has already drawn around 1 billion euros of the promised bank and government loans, while an agreement with unions on wage freezes for the next five years paved the way for the release of the remainder of the support package earlier this month.

(Reporting by Bart Meijer; Editing by Keith Weir)

By Bart H. Meijer