By Chris Buckley

TIANJIN, China, Oct 5 (Reuters) - Greenhouse gas cuts vowedby rich nations remain far from enough to escape dangerousglobal warming, a top Chinese climate official said on Tuesday,urging talks over a new climate change pact to confront theshortfall.

China is the world's biggest polluter of greenhouse gasesfrom human activity and its emissions are sure to keep growing.

But Su Wei, the head of the climate change office atChina's National Development and Reform Commission, saidwealthy countries with their much higher emissions per head ofpopulation should make space for emerging economies.

"The emissions targets of developed countries should bedramatically raised," he told a news conference at U.N. climatetalks in the northern Chinese city of Tianjin. This, he said,would "create the room necessary for developing countries'emissions".

Negotiators from 177 governments are meeting in Tianjintrying to coax agreement on what should follow the currentphase of the Kyoto Protocol -- the key U.N. treaty on fightingglobal warming -- which expires in 2012.

Officials in Tianjin are seeking consensus on climatefunding for developing countries, policies and funds to protectcarbon-absorbing forests, and transfers of green technology.

They hope that a higher level meeting in Cancun, Mexico,late this year can then settle the foundations of a bindingpact that could be agreed in 2011.

Fraught negotiations last year failed to agree on a bindingtreaty and culminated in a bitter meeting in Copenhagen, whichproduced a non-binding accord that later recorded the emissionspledges of participant countries.

TRUST-BUILDING

Talks so far this year have focused on trust-buildingfunding goals, with little talk about countries' targets toreduce greenhouse gases from fossil fuels and other sourcesblamed for heating up the atmosphere.

Su told reporters that the question of wealthy countries'emissions targets could not be avoided at Cancun. It was goodthat rich nations had offered emissions cut goals as part ofthe Copenhagen Accord, he said.

"But these goals are certainly still far removed from theexpectations of developing countries and from what is requiredaccording to science," he added.

The United Nations says the current targets would notprevent a temperature rise of more than 2 degrees Celsius (3.6F), which the EU and some experts have defined as the thresholdof dangerous climate change auguring worsening droughts, floodsand rising sea levels.

Under the Copenhagen Accord, supported by more than 110countries, parties agreed to limit warming to below 2 degreesCelsius from pre-industrial levels but didn't specify a date.

"To achieve a balanced outcome at the Cancun conference,the emissions reduction targets of developed countries must bediscussed," he said. "We can't discuss just other elements, butnot discuss these emissions reductions."

Su did not say what specific demands, if any, China couldmake over developed economies' emissions goals.

President Barack Obama wants to cut the United States'greenhouse gas emissions by 17 percent by 2020 from 2005levels, or 4 percent from 1990 levels. But legislation to thatend has failed to win the backing of the U.S. Senate.

The European Union has offered to cut emissions by 20percent by 2020, compared to 1990 levels, or 30 percent ifothers act.

Many Western governments and quite a few developingcountries want China to take on firmer internationalcommitments eventually to cap greenhouse gas emissions.

Officials have said they hope the Tianjin talks can reachbroad agreement on how to manage adaptation long-term funds andgreen technology to help poorer countries, as well as a shorterterm infusion of $30 billion a year to help those countries.

Su said China wanted to ensure that the wealthy countriesdid not treat that climate aid as their money to control. (Editing by David Fogarty)