Climate change deal: 'Zero carbon' laws promised by government
Climate laws will be tightened to cut carbon emissions effectively to zero, the government has said.
Under current law, emissions must be cut by 80% by 2050 - but ministers have said this does not go far enough.
Following the climate deal in Paris, it is clear the UK must not increase CO2 at all because the warming threat is so severe, they added.
No details of the law change have been given - and critics said the UK was failing to meet even current targets.
The global climate agreement, which was finalised at a summit in Paris in December, commits to keeping global temperatures "well below" 2C (3.6F) above pre-industrial times and limit the amount of greenhouse gases emitted by human activity.
Speaking in the Commons, energy minister Andrea Leadsom said government believed it was necessary "to take the step of enshrining the Paris commitment to net zero emissions in UK law".
"The question is not whether but how we do it. And there are an important set of questions to be answered before we do," she said.
"This is an example once again of the House demonstration on a cross-party basis a determination to tackle climate change."
The statement was welcomed by the cross-party group of MPs which pressed for the climate law to be tightened.
Ex-Labour leader and former Energy and Climate Change Secretary Ed Miliband told BBC News: "This will send a signal to other countries this is the right thing to do.
"We very much welcome what they (ministers) have done - now we've got to make sure the government deliver on it."
However, many in the energy sector will be baffled by what they see as a schizophrenic attitude to climate change from the government.
While pledging their allegiance to very demanding CO2 cuts, ministers have made a slew of policy changes that are predicted to increase emissions.
Ministers expected that by 2030 the UK would be mainly powered by nuclear, offshore wind and gas with carbon capture technology - which takes the emissions from a chimney and buries them in rocks.
But the government has failed to secure any new nuclear stations, scrapped a competition for carbon capture and threatened cuts in the offshore wind budget unless costs radically fall.
It has also turned its back on the cheapest forms of renewable energy - onshore wind and large scale solar energy and increased the tax on small low-emissions cars so the owner of a Prius pays as much vehicle excise duty as a Porsche.
The decision was followed by an increase in the purchase of the most polluting cars.
The government climate law announcement follows the tabling of an amendment to the Energy Bill by Mr Miliband and a cross-party group of MPs from six parties: Labour, Conservative, Liberal Democrat, Green, Plaid Cymru and SDLP.