The UK's legal targets to tackle climate change should be strengthened by 2020 to include a goal to cut emissions to "net zero", a report has urged.
A study on the impact of the Climate Change Act since it came into force a decade ago said it has been key in cutting the UK's greenhouse gas emissions, particularly from the power sector, while the economy has grown.
But the legislation, which has a goal to cut emissions by 80% by 2050, needs to be updated to bring it in line with the global Paris Agreement, experts from London School of Economics and Political Science (LSE) said.
The world's first comprehensive agreement on climate change commits countries to keeping temperatures "well below" 2C above pre-industrial levels.
Meeting the target will require the world's greenhouse gases to fall to net zero in the second half of the 21st century, with any emissions put into the atmosphere countered by measures to take greenhouse gases out of the air.
While the Climate Change Act is "technically consistent" with the Paris deal, legislation should be updated to reflect the net zero commitment, said the report by the Grantham Research Institute on Climate Change and the Environment and the ESRC Centre for Climate Change Economics and Policy at LSE.
Legislation should be bolstered by 2020, to coincide with updated pledges for action being submitted by countries under the Paris Agreement and ahead of the UK setting carbon reduction targets for the mid 2030s, it said.
The report's authors also warned that, while there has been political consensus for the Climate Change Act since it was brought in in 2008, commitments have wavered at times and it is "only ever one political appointment away from difficulties".
And the gap between the emissions targets set in law and the policies put in place to meet them is widening, with the UK currently not on track to meet its statutory carbon targets for the late 2020s and early 2030s.
"The Government's ability and willingness to close the gap between targets and delivery is perhaps the most tangible test of its commitment to climate change."
The authors also said: "The consensus for action on climate change in the UK has held but buy-in across government departments is too uneven.
"All parts of government must be fully committed to implementation of the Act as the UK moves into a more challenging phase of emissions reductions."
The report draws on interviews with MPs and peers, government advisers, senior officials and experts to assess the impact of the Climate Change Act, which became law in 2008.