Federal Court reserves Adani decision

The Australian Conservation Foundation must wait to learn if its latest challenge against the controversial Adani coalmine in Queensland's Galilee Basin has been successful.

The ACF appeared before the Federal Court in Brisbane on Friday to appeal a decision last year that gave the huge Carmichael project the green light.

But the full bench reserved its judgment after it heard submissions from the environmental group, federal Environment Minister Josh Frydenberg and Adani.

ACF barrister Saul Holt QC argued the original judge had erred when he found in favour of Mr Frydenberg and the Indian mining giant in August.

Mr Holt claimed the environment minister had not applied or misconstrued the law when he claimed if the mine didn't go ahead, the same amount of coal could still be produced somewhere else in the world.

Mr Holt said the argument failed to address the impact the Adani mine would have on global warming and in particular, warmer water temperatures on the Great Barrier Reef.

"What someone else might do if this action doesn't go ahead is irrelevant," he said.

"The harm is still done by the emission of the carbon by Adani's coal."

However Richard Lancaster SC, representing Mr Frydenberg, said the original judge was correct when he agreed his client could only be "speculative" when it came to the impact Adani's possible emissions would have on global warming.

Mr Lancaster said the projection that 4.64 billion tonnes of coal, or one-183rd of total worldwide emissions, could be produced by the Queensland mine was the "worst case scenario".

Mr Lancaster said neither the original judge nor the environment minister had erred in their interpretation of the relevant acts.

The full bench of the Federal Court will hand down its decision at a later date.