* Prime Minister Aso to decide 2020 target by mid-June
* Study shows marked impact of 25 pct cut on households
* Aso says most comments from public on plus 4 pct option
TOKYO, May 29 (Reuters) - The high costs Japan would incur if Tokyo promises to cut greenhouse gas emissions by 25 percent from 1990 levels by 2020 would be hard for the public to accept during the recession, Prime Minister Taro Aso said on Friday.
His comments showed there was still no consensus within the government after Environment Minister Tetsuo Saito said earlier this week that setting a mid-term target for cuts in a range of 15 to 25 percent was one option. [ID:nT207755]
Aso has said he would announce Japan's mid-term target by mid-June, so he can set out Japan's views at a July meeting of G8 leaders and a U.N. conference in December that is meant to agree a new global climate pact to replace the Kyoto Protocol.
Japan, the world's fifth largest emitter, is under great pressure from developing nations to show leadership by opting for deep emissions reductions to ensure a strong outcome in December's gathering in the Danish capital Copenhagen.
A panel of experts, professors and industry officials has presented Aso with a choice of six target options relative to 1990 levels. It said that curbing carbon dioxide (CO2) emissions by regulations or other measures would boost energy costs, increase job losses and thus have a net negative impact on the economy.
The other five options, ranging from an increase of 4 percent to a cut of 15 percent, all fall short of a 25-40 percent cut required of rich nations by a U.N. panel of scientists to minimise the risk of the worst impacts of global warming.
"At a time of deep recession like this, it would be difficult to ignore the (larger) costs for the public to bear," Aso said, when asked about the minus 25 percent option.
"To trust their morale only would not be the resolution," Aso told a budget committee in Friday's parliament session.
Aso referred to an assessment by economists of the effect of each option on the economy, which showed under the minus 25 percent target scenario, energy costs in 2020 would be 140,000 yen ($1,453) per household per year more than those under the weakest one.
The same estimate also showed annual disposable income per household would be 220,000 yen less than that under the weakest option, in which users are allowed to keep the current pace of buying low-emission goods and facilities, resulting in emissions exceeding by 4 percent from 1990 levels by 2020.
Aso also told the same committee that he would take into account that the plus 4 percent option attracted the largest number of comments from the public in the past month.
How to gauge voters' views is critical for Aso as public opinion polls put the opposition Democrats ahead of his Liberal Democratic Party in the run-up to an election, which many speculate will be in August and must be held by October. [ID:nT369707] ($1=96.37 Yen) (Reporting by Risa Maeda, editing by Anthony Barker)