Similar growth in India, Brazil, Russia, Indonesia and elsewhere risks endangering a goal to avoid dangerous global warming, which the European Union and some scientists put at 2 degrees Celsius or more, the PwC economics report said on Friday.

Carbon capture and storage (CCS) is a barely tested technology that involves burying the commonest greenhouse gas, CO2, underground. But it is essential to curb emissions in the long run, the report said.

"CCS is necessary to be on path to stabilisation at 450 parts per million," said the report's author, PwC's UK head of macroeconomics John Hawksworth, referring to the atmospheric CO2 level that some scientists match to a 2 degrees rise.

CCS is seen especially applicable to China and its huge reserves of highly-polluting coal, because of the option to split coal into CO2 and hydrogen and bury the CO2.

PwC estimated that CO2 emissions would fall by 17 percent by 2050 using both CCS and other clean energy technologies, but would rise by 4 percent without CCS.

Climate scientists have previously estimated to Reuters that a 16 percent cut by 2050 would still have a roughly two-thirds chance of exceeding 2 degrees.

CCS is still at a demonstration stage, adding urgency to development of the technology, Hawksworth said.

"There's no room for delay to be ready to roll it out on a large scale by 2025."

Given this time gap, in the meantime the world will need to apply energy efficiency technologies in power plants, cars, houses, and appliances, to keep pollution under control.

Besides CCS, clean energy sources like renewables will be necessary to achieve the further necessary emissions cuts to 2050.