"Let me make myself absolutely clear - I am firmly opposed to this expansion of Heathrow Airport as it runs contrary to all the growing evidence we now have on the impact of aviation on climate change," said Livingstone.
"Only last week the latest United Nation's Intergovernmental Panel Climate Change report warned of the very real threat of abrupt and irreversible climate change if we continue to allow carbon emissions to grow.
"Half of the population never fly at all from one year to the next, and of course it is vital to maintain business and long haul air travel, but a small proportion of people are taking ever more short haul leisure flights.
"The Government will need to demonstrate why demand for such trips couldn't be better met by investing in rail infrastructure, and if this happened why additional runway capacity would still be needed."
Transport secretary Ruth Kelly this morning unveiled proposals for a third runway and sixth terminal by 2020, in move which runs contrary to the 2003 Future of Air Transport white paper. The consultation "Adding Capacity at Heathrow Airport" covers a range of different proposals for the future development of the airport including a third runway and mixed mode operation.
The Conservative Party has broadly supported the proposals, provided that it can be demonstrated that strict environmental limits for noise and pollution can be met.