Now the party will demand the EU goes much further, on the back of its stunning local election successes which have raised hopes for the European Parliament polls on 23 May.
“Anyone who wants to stop our climate crisis should vote to stop Brexit,” Sir Ed, a former climate change secretary, told The Independent.
“If Britain leaves the EU, we leave Europe's key climate talks. We cannot influence 27 other countries on climate change without a seat at the table and therefore we will witness the influence we have on the world through the EU dramatically reduced.”
Pointing to 704 gains, which made the Lib Dems the town hall winners last Thursday, he added: “It's now clear that to stop Brexit people need to vote Liberal Democrat.”
The move follows last week’s call by the Committee on Climate Change (CCC) for the UK to act “now” to enact a legally binding duty to achieve net greenhouse gas emissions by 2050.
The blueprint would mean the end of petrol and diesel cars and gas boilers, a drastic cut in people's meat consumption, and the planting of at least 1.5 billion trees.
The target is for net zero emissions because greenhouse gases from some activities, including air travel and farming, will remain unavoidable by 2050.
These would be balanced by taking carbon out of the air by growing trees or burying carbon dioxide below ground level.
Downing Street said only that she will “respond urgently” to the call for new laws - pointing to the need to examine a “long and detailed” report first.
John Gummer, the CCC's chairman, had called for the zero-emissions target for 2050 to be made law immediately, saying: “We must do it now. The urgency is not just a matter of a shortness of time - the quicker you do it the cheaper it is.”
The Liberal Democrats are also calling for a UK target of net zero emissions by 2045 – five years earlier than the CCC proposal and the party’s aim for the EU as a whole.
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