* Japan dramatically waters down CO2 emissions target
* Change made inevitable when nuclear plants shut due to Fukushima
* "I have no way of describing my dismay," says Chinese delegate
(Adds quotes, analysis throughout)
TOKYO/WARSAW, Nov 15 (Reuters) - Japan drastically weakened its greenhouse-gas reduction target on Friday, bowing to the impact of a shuttered nuclear power industry but drawing international criticism at U.N. climate change talks.
The government decided to target a 3.8 percent cut in CO2 emissions by 2020 versus 2005 levels. That amounts to a 3 percent rise from 1990 levels - a sharp reversal of the previous target of a 25 percent reduction, the benchmark level for climate talks.
The new goal marks a dramatic turnaround for a nation that had championed the earlier Kyoto treaty on climate change. But it said it was made inevitable when the nation's 50 nuclear plants were closed after the March 2011 earthquake and tsunami which wrecked the Fukushima reactors northeast of Tokyo.
"Given that none of the nuclear reactors is operating, this was unavoidable," Environment Minister Nobuteru Ishihara told reporters.
Prime Minister Shinzo Abe advocates a return to nuclear power, although he says he wants to reduce Japan's reliance on it 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.
The loss of nuclear, 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.
The Japanese delegation got a standing ovation when it arrived at U.N. talks in Bangkok in 2009, weeks after then-Prime Minister Yukio Hatoyama announced the 25 percent target.
In contrast, recent leaks about Tokyo's target revision in the Japanese media have led to Japan being vilified in Warsaw.
"This move by Japan could have a devastating impact," said Naoyuki Yamagishi of environmental campaigners, WWF Japan. "It could further accelerate the race to the bottom among other developed countries."
Asked about Japan's new target, lead Chinese climate negotiator Su Wei said: "I have no way of describing my dismay."
Natural-gas consumption by Japan's 10 utilities was up 8.4 percent in October from a year earlier and coal use was up 4.4 percent as the companies used more fossil fuels to compensate for the nuclear shutdown, industry data showed on Friday.
With Abe facing opposition to nuclear power even from within his own party, the weaker emissions commitment could be an argument for restarting reactors, given that Japan for decades has touted the clean energy.
"Our energy mix, including the use of nuclear power, is currently being reviewed," said Chief Cabinet Secretary Yoshihide Suga. "In that context, we decided to set this target at this point."
Hiroshi Minami, Japan's chief negotiator at the U.N. talks, said the watered-down goal "is based on zero nuclear power" in the future.
"I expect I will face significant criticism," Minami said in Warsaw, where the talks are continuing through next week.
At the same time, the nuclear shutdown could prove convenient for Abe in that it allows his government to abandon a target that some say was too optimistic.
"Anyone could have seen that this was just impossible - it was predicated on a nuclear ratio of at least 50 percent," said energy analyst Akira Ishii. "All the people involved, including METI (Ministry of Trade and Industry), knew even before (the 2011 disaster) that it was impossible."
Poor nations want the developed world to commit to deeper emissions cuts while providing more climate finance, a key issue at the Warsaw talks after the central Philippines was ravaged by super typhoon Haiyan, one of the most powerful storms ever recorded.
However, while countries including the United States, Canada and Australia have been targeted by green groups for doing too little on climate change, Japan had largely been left out of the firing line due to its ambitious 2020 goal.
(Additional reporting by Michael Szabo in WARSAW and Osamu Tsukimori in TOKYO; Writing by William Mallard; Editing by Ed Davies)