Carbon intensity does not measure the actual amount of greenhouse gas emissions; it shows the amount emitted relative to its economic output, such as manufacturing and services, in effect measuring the efficiency of energy use.
China, the world's biggest emitter of greenhouse gases, has rarely given news conferences at previous climate talks and the possibility that Beijing and Washington were close to an agreement rose last month when they unveiled emissions targets within a day of each other.
Developing world anger
But two days into the December 7-18 talks in the Danish capital, long-running north-south rifts have dampened hopes of reaching a robust global agreement among the 192 nations represented at the summit.
Su's remarks came on the same day that a draft Danish proposal for a political agreement caused an uproar at the summit, overshadowing a decision by the US, announced just hours earlier, to treat six greenhouse gases as a human health hazard.
Environmentalists had hailed the US announcement on Monday and welcomed the timing, saying that allowing Barack Obama to sidestep congress to order emission cuts would help the US president convince Copenhagen delegates the US was serious about addressing climate change.
North-south divisions flare again over draft Danish proposal at Copenhagen summit
But just hours later, developing nations were expressing anger over the Danish draft that was circulated informally.
If accurate, the proposal would see more power handed to rich nations, the negotiating role of the UN sidelined and the Kyoto protocol abandoned.
The head of the G77 group of developing countries said on Tuesday that the draft proposal "threatens the success" of the summit.
Sudan's Lumumba Stanislas Dia Ping, who heads the G77 group, said members "will not sign an inequitable deal".
"We can't accept a deal that condemns 80 per cent of the world population to further suffering and injustice," he added.
Su said it was "unfair" to set a limit on nations that were still developing when emissions of developed countries were still going up.
'Not enough for coffin'
He also said a mooted annual $10bn financial help from rich nations to developing ones as a drop in the ocean.
|Su said the US, EU and Japan had not brought enough to the table [AFP]
"If divided by the world population it is less than $2 per person," he said, adding that this would not cover a coffee in the rich world or a coffin in poor countries that are at the sharp end of climate changes.
Su said that the success of the Copenhagen talks hinged in part on the offer brought to the table by the US, but dismissed the target for 2020 that Obama has laid out, criticising Washington for failing to rein in its emissions, unlike other developed nations.
"Currently the target is to reduce emissions 17 per cent from the 2005 level, I think for all of us this figure cannot be regarded as remarkable or notable," he said.
Su said all the rich nation targets broadly fell short of the emissions cuts recommended by a UN panel of scientists.
The panel has said reductions of 25 to 40 per cent below 1990 levels by 2020 were needed to avoid the worst effects of global warming.
He called a unilateral EU cut of 20 per cent insufficient, and even a sharper 30 per cent cut - which the bloc has said it may shift to depending on other cuts - was still too easy.
Su also attacked the new government in Japan for setting "impossible" conditions on its offer of a 25 per cent cut by 2020, which was a considerable increase on the goal set by the previous administration.
Japan, the world's fifth largest emitter, has said its commitment depends on ambitious targets being agreed to by major emitters.
Su said the demands on poor nations violated international agreements that allowed them to put economic growth first, and the demands on the US were unrealistic given its clear stance on climate change.
"The Japanese have actually made no commitment because they have set an impossible precondition," he said.