Heathrow Expansion Could Break UK Climate Laws

British lawmakers have said government plans to expand Heathrow and other UK airports would violate national climate laws and rely on green technologies that are unproven or unrealistic.

A cross-party committee of MPs said in a report released Friday that aviation emissions will surge if airport expansions proceed, and push Britain past legal carbon limits.

"The Government should not proceed with further expansion until it has demonstrated how such growth is compatible with its carbon budgets and environmental targets," the committee said.

The government recently approved a third runway at Heathrow and a second at Gatwick, and backed expansions at other airports.

It and the aviation industry had argued that expanding the airports were vital for the UK’s economic growth and that sustainable aviation fuel, carbon offsetting, and more effi