Rallies have taken place in several Australian cities against the introduction of a carbon tax.
Many of the demonstrators in Canberra were over the age of 60. The ABC reports they fear the tax will increase their household bills.
The federal government plans to tax industrial polluters for the carbon dioxide they release.
Prime Minister Julia Gillard says she remains committed to the policy, despite the protests.
But opposition leader Tony Abbot says that without a global agreement, the levy would make Australian businesses less competitive.