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Government must mitigate environmental impact of new Heathrow runway

23 February 2017

The Government is still not doing enough to demonstrate that it can mitigate the environmental impacts of the planned new runway at Heathrow, MPs on the cross party Environmental Audit Committee have found.

Mary Creagh MP, Chair of the Environmental Audit Committee, said:

"If the Government wants to get Heathrow expansion off the ground it needs to show that a third runway can be built and run without exceeding legal limits on air pollution or breaching our carbon budgets.

We have seen little evidence of the 'step change' in the Government's approach we called for in our previous report.

Worryingly, the Government looks set to water down the limits on aviation emissions recommended by its own climate change advisors. That would mean other sectors of the economy, like energy and industry, having to cut their carbon emissions even deeper and faster.

Mitigating the air quality, carbon and noise impacts of a new runway cannot be an afterthought. Ministers must work harder to show that Heathrow expansion can be done within the UK's legally binding environmental commitments."

Air Quality 

The UK has already breached EU NO2 limits in London for 2017. A new air quality strategy is urgently required to ensure that airport expansion is not granted at the expense of public health.  The Committee is concerned that the Government has given no guarantees that air quality targets will be maintained after the UK leaves the EU.

The promise not to increase road traffic at Heathrow needs to be rigorously monitored, with clear accountability and consequences for failure. The MPs are concerned that the Government is relying on people switching to cleaner cars to reduce air pollution but have no confidence the Government will meet their targets for uptake. The report calls on the Government to implement an alert system for people who are especially vulnerable to short-term exposure to air pollution in London.

Carbon emissions

Scant detail has been provided on the Government's approach to carbon emissions limits. The figures used by Ministers for the costs and benefits of expansion are based on a hypothetical international framework to reduce emissions which does not yet exist. The figures would leave international aviation emissions 15% higher than the level assumed in the UK's Fifth Carbon Budget, which runs from 2028-32.

The Government is considering rejecting the recommendations of the independent Committee on Climate Change on the most cost-effective way to reduce carbon emissions. The Government should publish an independently scrutinised strategy to reduce carbon emissions from international aviation and set out the resulting costs on other sectors to test their feasibility and desirability.


Measures on noise lack ambition; with no precision offered on the timing of a night flight ban and little evidence that predictable respite can be achieved. The case for an Independent Aviation Noise Authority with powers to enforce policy recommendations remains clear. The Committee is concerned that the Government is watering down the powers it intends to give to a new noise oversight body.

Further information

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