Japan on Friday drastically weakened its greenhouse-gas reduction target, bowing to the impact of a shuttered nuclear power industry but drawing international criticism at United Nations climate change talks.

The change in the carbon dioxide-emissions goal is a dramatic turnaround for a nation that had championed the earlier Kyoto treaty on climate change.

But it was made inevitable when the nation's 50 nuclear plants were closed in the wake of the March 2011 earthquake and tsunami that wrecked the Fukushima facility northeast of Tokyo.

The government decided to target a 3.8 percent cut in CO2 emissions by 2020 versus 2005 levels, Chief Cabinet Secretary Yoshihide Suga told a news conference. That amounts to a 3 percent rise from 1990 levels - a sharp reversal of the previous target of a 25 percent reduction from 1990 levels, the benchmark level for climate talks.

"The new target is based on zero nuclear power in the future. We have to lower our ambition level," said Hiroshi Minami, Japan's chief negotiator at the UN talks taking place in Warsaw.

Prime Minister Shinzo Abe advocates a return to nuclear power, although he says he wants to reduce Japan's reliance on nuclear over time. The process of restarting reactors will be slow, starting early next year at the soonest, and some will never come back on line due to safety concerns after Fukushima.

The loss of nuclear power, which had accounted for 26 percent of Japan's electricity generation, has forced the country to import dirtier natural gas and coal, causing its greenhouse gas emissions to skyrocket.

Japan will aim to cut emissions by 2.8 percent through planting trees, while the remainder will be done by reducing emissions from energy and industry or by using carbon credits bought from other countries.

Minami said the 2020 target could be revised again if Japan reintroduces nuclear into its energy mix.

Japan also pledged $16 billion by 2015 to help poorer nations reduce their emissions and adapt to the effects of climate change, such as higher sea levels and more droughts.

Minami said the aid will be a mix of grants and loans, with $13 billion coming from the government and the rest from the private sector.

Reuters