A Queensland farmer has cut a giant message in his field to urge G20 organisers to add climate change to the agenda for this month's leaders' summit.

Rob McCreath said he was prompted to take action after Brisbane Airport rejected a billboard calling for climate change to be put on the G20 agenda.

He ploughed the message "Go Solar" into a field on his property at Felton, south of Toowoomba.

"I hope [German chancellor] Angela Merkel shirt-fronts Tony Abbott and asks him, 'If Germany can go solar then why on earth can't Australia?'," Mr McCreath said.

He said farmers were at the "pointy end" of climate change.

"Last year was our hottest on record, this one's shaping up to be even worse, and we've got a raging drought over a vast area," he said.

"In spite of the overwhelming scientific evidence, our idiotic politicians are hooked on coal and gas, which is the cause of the problem.

"We have huge reserves of sunshine, so making use of it is simply a matter of common sense.

"Our Government's reluctance to do so is an international embarrassment.

"Unlike coal, solar power really is good for humanity because it can provide the clean energy needed to lift people out of poverty across the world, without stuffing up the climate even more."

Earlier this year Foreign Minister Julie Bishop told a Melbourne summit the G20 should not try to "cover all subjects and illuminate none".

"We must prioritise issues where there is consensus within the G20 on taking action," she said.

"All G20 members agree that the United Nations framework convention on climate change is the right forum with the right mandate for international climate change negotiations."

Mr McCreath was a member of the lobby group Friends of Felton, which successfully campaigned against a coal mine in the area.

In 2012, Premier Campbell Newman confirmed no coal mine would be allowed in Felton.