More than 45,000 people marched through the streets of Sydney on Sunday on the eve of the Paris climate summit, dpa reported. The Sydney march was the largest in three days of rallies in cities and towns across Australia, calling for action on climate change. An estimated 40,000 people marched in Melbourne on Friday, followed by 10,000 in Brisbane Saturday. On Sunday, rallies drew crowds of 6,000 in Canberra, about 5,000 in Adelaide, 1,000 in Hobart, and more than 300 in Perth. Four students dressed in bright orange, pink and green balloons representing the tropical oceans said the Paris talks were vital to the future of the planet. "It's an emergency and if we don't all act it will become a catastrophe," David Sindel said.