The Paris climate deal aims to limit global temperature rises to 1.5 degrees Celsius, committing nations to reduce their greenhouse gas emissions to this end. / © dpa/AFP/File
Britain on Thursday became the world's first major economy to adopt the tough new target of lowering fossil fuel emissions to a level of net zero by 2050.
Energy and Clean Growth Minister Chris Skidmore signed an order paper enacting the legislation after it passed both houses of parliament without a vote earlier this week.
Britain is already on course this year to make low-carbon sources such as wind and solar responsible for more than half of all its power generation for the first time since the 1800s.
"The UK kick-started the Industrial Revolution, which was responsible for economic growth across the globe but also for increasing emissions," Skidmore said in a statement.
"Today we're leading the world yet again in becoming the first major economy to pass new laws to reduce emissions to net zero by 2050 while remaining committed to growing the economy."
The deadline is more ambitious than Britain's previous policy of cutting emissions by 80 percent over the same period.
- 'Incredible progress' -
The stringent new guidelines will require a fundamental change in how the UK economy functions that some have warned may carry prohibitive costs.
Philip Hammond's finance ministry has reportedly issued a study showing that a shift to net zero from current targets could cost more than £1.0 trillion ($1.3 trillion, 1.1 trillion euros) over 30 years.
But the top UK advisory body on climate change said the new target could be achieved within a less costly budget of 1.0-2.0 percent of gross domestic product by 2050.
The Committee on Climate Change (CCC) said this would require the rapid rollout of new policies such as making all new cars and vans electric by 2035 and quadrupling low-carbon electricity production.
Britain is already making some progress.
The National Grid network operator said this month that green sources of energy -- including nuclear -- would make up more than half of all the power generated across the country in 2019.
National Grid chief executive John Pettigrew said the achievement highlighted the progress Britain has made weaning itself off its past dependence on polluting coal.
Britain was home to the world's first coal-fuelled power plant in the 1880s.
"The incredible progress that Britain has made in the past 10 years means we can now say 2019 will be the year zero-carbon power beats fossil fuel-fired generation for the first time," Pettigrew told reporters.
- 'Cap and trade' -
The CCC said there would be a greater than 50-percent chance of limiting the average global temperature rise to 1.5 degrees Celsius -- the "safe" limit identified by the UN's Intergovernmental Panel on Climate Change -- if Britain's move was replicated across the world.
"We're pioneering the way for other countries to follow in our footsteps driving prosperity by seizing the economic opportunities of becoming a greener economy," Skidmore said.
The government definition of "net zero" means that emissions are balanced by schemes to offset them.
These include planting trees or using technology to capture and store carbon emitted from burning coal and oil.
Natural gas is a less-polluting fossil fuel that some economists see as a temporary option industries could adopt towards the net zero target.
Britain is also part of the EU Emissions Trading Scheme -- a so-called "cap and trade" mechanism that has come under heavy criticism from environmental campaigners.
It tries to lower emissions by setting a price for carbon. Nations that exceed their emissions "cap" can purchase the non-used portions allocated to low-emitting nations.
Environmental campaigners say pollution has no national borders and that emissions trading does nothing to lower the global amount of greenhouses gases in the atmosphere.