While the Intergovernmental Panel on Climate Change made its conclusion on the cause of global warming, some scientists have cast doubt on the report.

Earlier, more than a thousand e-mails sent between some of the world's top climate specialists have been exposed by hackers, drawing questions about the seriousness of global warming.

Scientists casting doubt on global warming have taken their plea to Copenhagen where they are holding a rival conference. This follows the discovery of e-mails written by climate specialists accusing them of colluding to suppress others' data and enhance their own.

Increased carbon dioxide does not cause global warming according to these climate change sceptics.

Ian Plimer, Professor of Mining Geology, Adelaide University, said, "Pollution kills us and carbon dioxide is not a pollutant. It makes plants grow. And without carbon dioxide, we don't eat."

However, others argue that reducing carbon emissions is still a necessity.

While the Intergovernmental Panel on Climate Change made its conclusion on the cause of global warming, some scientists have cast doubt on the report.

Tom Picken, Friends of the Earth, said, "The science is very clear of what we need to do to avoid catastrophic climate change. Developed countries need to commit and achieve reductions of at least 40 percent by 2020 excluding offsetting."

The argument over how to tackle climate change began heating up last week.

Sceptics claim that e-mails out of the UK's East Anglia University's Climatic Research Unit show that some of the scientists there were trying to manipulate some of the evidence on global warming.

Some of that data has been used in formulating the reports of the Intergovernmental Panel on Climate Change which is the basis of discussion for the climate summit.

Ian Plimer, Professor of Mining Geology, Adelaide University, said, "What is really interesting is that we have just recently seen that a huge amount of the data and the people involved in driving the IPCC have actually lost some really important data."

The skeptical scientists gathering in Copenhagen have said that those IPCC scientists at the climate summit involved in the hacked emails controversy, should be held legally responsible.

(CCTV December 11, 2009)