A leaked draft of a major United Nations climate change report has revealed scientists are almost certain human activity is causing global warming.
Drafts of the Intergovernmental Panel on Climate Change's (IPCC) fifth assessment report says it is 95 per cent likely that humans were the principal cause of warming.
The findings mark a 5 per cent increase from 2007's fourth assessment report.
The document will also attempt to explain why the increase in global temperatures has slowed since 1998, despite greenhouse gas concentrations reaching record highs.
In May, a report published in the journal Nature Geoscience said the .
The IPCC said it would be premature and misleading to draw too many conclusions from the leaked draft.
"Draft reports are intermediate products and should not be represented as the final scientific view [of the IPCC]," a statement read.
"The text is likely to change in response to comments from governments received in recent weeks and will also be considered by governments and scientists at a four-day approval session at the end of September."
Leaks of such reports are common, in part because they are sent to so many people.
Hundreds of scientists, governments and non-government organisations involved in the process receive copies, the contents of which are supposed to remain confidential.
In December 2012 a on climate sceptic websites.
The 14 chapters were posted on a US-based blog site called stopgreensuicide and another site critical of climate science.
The ABC has confirmed the latest draft report also predicts that sea levels will rise by between 29 and 82cm by the end of the century, with scientists fairly confident that will be the upper limit.
A separate report published in the journal Nature Climate Change has suggested climate change combined with population increases, growth and land subsidence could significantly increase the risk of floods in large port cities over the next four decades.
The authors looked at present and future flood losses in 136 of the world's largest coastal cities.
Average global flood losses in 2005 were around $6.6 billion, but the study suggests that could increase to $70 billion by 2050.