LONDON - The British government pledged Tuesday to cut the country's carbon emissions in half by 2025, but the ambitious target could be jettisoned if other European countries don't join in cutting their emissions.

Energy Secretary Chris Huhne told Parliament that Britain would reduce emissions by about 50 percent from benchmark emission levels in 1990, part of a legally mandated commitment to reduce greenhouse-gas emissions by 60 percent by 2030, and 80 percent by 2050.

Huhne cast the dramatic cuts as a massive boost to green-technology companies, telling parliamentarians he was putting Britain "at the leading edge of the global low-carbon revolution."

But energy-intensive industries, such as steel manufacturers, warned that the country risked making itself uncompetitive unless other European countries followed its lead.

They have pressured the government to put in an escape clause that allows for the target to be scrapped as soon as 2014 if Britain's European partners fail to implement their own carbon cuts.

David Cameron, Britain's prime minister, made the same point in separate comments to lawmakers Tuesday.

"It doesn't actually help climate change if you simply drive an energy-intensive industry to locate in Poland rather than Britain," Cameron told lawmakers. "We believe that Europe should follow our lead and go for a 30 percent reduction."

Carbon dioxide - spewed into the atmosphere by cars, planes, factories, and power plants - is a major driver of human-made climate change, which scientists say is already leading to global warming and melting ice caps.

Britain emitted nearly 800 million tons of greenhouse gases in 1990, but although the amount has fallen significantly in the last two decades, environmental activists say more must be done and faster. Legislation passed in 2008 made the goal of implementing an 80 percent cut by 2050 legally binding.

Still, there's lingering opposition to the reductions. Britain is trying to emerge from a deep recession, and business leaders have argued for a reprieve.

The issue split Cameron's cabinet, which is composed of lawmakers from the business-friendly Conservative Party and the green-conscious Liberal Democrats, of which Huhne is a senior member.