The UN's official panel on climate change has hit back at sceptics' claims that the case for human influence on global warming has been exaggerated.
The Intergovernmental Panel on Climate Change (IPCC) said it was "firmly" standing by findings that a rise in the use of greenhouse gases was a factor.
It was responding to a row over the reliability of data from East Anglia University's Climatic Research Unit
Leaked e-mail exchanges prompted claims that data had been manipulated.
Last month, hundreds of messages between scientists at the unit and their peers around the world were put on the internet along with other documents.
Some observers alleged one of the e-mails suggested head of the unit Professor Phil Jones wanted certain papers excluded from the UN's next major assessment of climate science.
Professor Jones, who denies this was his intention, has stood down from his post while an independent inquiry takes place.
In a statement, Professor Thomas Stocker, co-chairman of the IPCC's working group 1, condemned the act of posting the private e-mails on the internet, but avoided commenting on their content.
He went on to point to a key finding that states: "The warming in the climate system is unequivocal.
"[It] is based on measurements made by many independent institutions worldwide that demonstrate significant changes on land, in the atmosphere, the ocean and in the ice-covered areas of the Earth.
"Through further independent scientific work involving statistical methods and a range of different climate models, these changes have been detected as significant deviations from natural climate variability and have been attributed to the increase of greenhouse gases."
He added: "The body of evidence is the result of the careful and painstaking work of hundreds of scientists worldwide.
"The internal consistency from multiple lines of evidence strongly supports the work of the scientific community, including those individuals singled out in these e-mail exchanges."
The row comes ahead of the Copenhagen climate summit which starts on Monday.
Earlier, the Met Office said it would publish all the data from thousands of weather stations worldwide, which it said proved climate change was caused by humans.
Its database is a main source of analysis for the IPCC.