Scientists with the Intergovernmental Panel on Climate Change (IPCC) insist that global warming is a reality despite the controversy arising from the stolen e-mails of climate scientists.

Latest findings continue to support the statement that "warming in the climate system is unequivocal," the key conclusion they made in the 2007 Climate Change Report, Thomas Stocker, a climate environmental physicist, said during a panel discussion on the sideline of the ongoing United Nations Climate Change Conference yesterday.

Stocker, lead author of the previous two IPCC reports, is leading a working group on the new Climate Change Report to be released in 2013.

By using the latest climate change models and studying chemical composition of rain and greenhouse gas, Stocker and his colleagues at the IPCC have discovered that the atmosphere now contains higher levels of CO2 than described in the 2007 report and its increase is more rapid than previously calculated.

Measuring polar-region ice

Ice is thinning on the margins of Greenland and Antarctica, he noted. There are areas where the ice is becoming thicker, but these zones are few and far between. Meanwhile, the sea ice over the Arctic is dwindling rapidly.

Stocker warned that there is a possibility that the sea level may continue to rise even when humans achieve zero carbon emissions.

Extreme weather have become more frequent, he said. Heat waves, for example, now occur once every four years, whereas they occurred once in 1,000 years according to data from centuries back, he said.

Stocker said the CO2 emitted in the past 10 centuries is causing "irreversible changes in the climate and in ocean chemistry."

Increased extreme weather will make it more difficult for the people to adapt to the climate changes, he said.

Hackers didn't upend data

As to skeptics' allegation after the e-mails hacked from climate scientists were revealed, Rajendra Pachauri, IPCC chair, defended its studies by saying that "the IPCC procedures are very robust, very reliable, and completely transparent."

"We have a variety of data sets that we access, and they all corroborate the conclusions that we have arrived at," Pachauri said.

Pachauri said his panel will "look into" the issue of the hacked e-mails to see if there is any lesson to be learned, adding that it didn't mean it would be carrying out an official investigation for any wrongdoing.

Private e-mails involving researchers at the University of East Anglia, who contribute to the IPCC's research, were hacked last month, stirring controversy and new claims by climate skeptics that climate data has been manipulated to exaggerate the case for global warming.