“Make no mistake. The tragedy unfolding in Australia is climate change-based,” he said in a message read out on stage by show host Jennifer Aniston.
Crowe won the award for his portrayal of Fox News Chief Executive Roger Ailes in The Loudest Voice in the Room.
His comments join a wave of celebrity support for the fire response.
At least 24 people have died since the fires began in September.
The fires are a natural part of the Australian weather cycle, but have been worsened this year by hotter-than-average temperatures and a persistent drought in many areas.
Crowe is one of thousands of Australian residents whose homes have been lost or damaged by the bushfires, which are affecting every state and territory.
“We need to act based on science, move our global workforce to renewable energy and respect our planet for the unique and amazing place it is,” he said in his message.
Crowe was not at the Golden Globes ceremony in Hollywood – Aniston said he had stayed at home to protect his family.
He has been posting regularly on social media since the fires began, about the damage to his home but also encouraging donations to the largely volunteer fire services.
His latest video showed his Golden Globe alongside his firefighting equipment.