A major new report has warned that Australia is already suffering from the social, economic and environmental impacts of a changing climate, and has backed the prime minister’s plans to tax carbon emitted by big polluters.

The first major report from Australia’s Climate Commission, published today, analyses the most recent climate change science, concluding that the impacts are already being felt in Australia despite warming of less than 1 degree Celsius globally.

The number of record hot days in Australia has more than doubled in the past 50 years, increasing the risk of heatwaves and associated deaths, as well as extreme bush fire weather, said the Commission.

The Critical Decade report (PDF) also warned that sea levels have risen by 20 centimetres globally since the late 1800s, affecting many coastal communities. Another 20cm increase by 2050, which is likely at current projections, would more than double the risk of coastal flooding.

Biodiversity and the economic risks associated with the Great Barrier Reef were also highlighted, noting that the area has suffered from nine bleaching events in the past 31 years.

The Commission said that decisions on tackling climate change should be made in this “critical” decade, and that carbon emissions “must peak within the next few years and then strongly decline”.

Speaking to reporters today, Commission chief Tim Flannery explained that, while carbon sequestration is useful, it should be combined with a carbon price to be effective.

He argued that storing carbon in land ecosystems would not provide the economic boost needed to help prepare the Australian economy as a whole for the challenges of climate change.

“We need to use whatever means we can to sequester carbon but also start reducing emissions from industry,” he said. “We need some sort of price on carbon. A price is unavoidable.”

Prime Minister Julia Gillard plans to introduce a carbon tax in 2012, but opposition leader Tony Abbott believes that climate change cannot be tackled through carbon sequestration alone.

Gillard welcomed the report in parliament today as bolstering the case for urgent action on climate change. She also accused Abbott of denying the existence of climate change.

Climate change minister Greg Combet also welcomed the report, saying that it showed that the longer the country waited to take action, the more it would cost.

“This is why the next decade is critical for getting the global economy on a less carbon intensive pathway,” he said. “Taking action on climate change is the right thing to do. It is the right thing for our economy, for jobs and for the environment.”

However, Abbott appeared unmoved by the report. Visiting a steel factory today, he described the carbon tax as “toxic” for heavy polluting companies which would face rising electricity prices as a result of the tax.

He welcomed the Commission’s findings, maintaining they were in line with his party’s plans.

“What the Commission report does is state that direct action would be ‘a rapid way’ of reducing emissions,” he said.

“Now, the argument here is not about climate change, the argument here is about how to deal with it and the Climate Commission report says that direct action is a rapid way of reducing emissions. It also says that soil carbon is going to be a very important factor in Australia getting its emissions down.”

By Jessica Shankleman