China will face social unrest if it fails to sustain average growth of at least seven per cent this decade, a mainland economist has warned. The vice-director of the China Society for Research of the Reform of the Economic System, Yang Qixian, was quoted by the China Business Times as saying even seven per cent annual growth of Gross Domestic Product was barely enough to rein in a rapidly widening income gap and assuage the simmering social discontent. State planners have set this rate as the target for the decade. Sustainable strong economic growth was necessary for the benefits of economic development to trickle down to low-income earners, such as farmers, Mr Yang said. 'The income of the majority of people in China may drop if China cannot achieve a seven per cent economic growth and income disparity will certainly widen. If we don't handle this well, the stability we've long emphasised will be at risk.' He said other acute social and economic problems facing China included unemployment, fiscal deficits, low efficiency of state enterprises and potential risks in the financial markets. These could only be relieved by strong economic growth. Critics have challenged the official target of seven per cent GDP growth until 2020 as unrealistic. But Mr Yang said even if seven per cent growth was achieved until 2010, much of the expansion would be offset by population growth, payment to service foreign debts and increases in public expenditure. Only about two of the seven per cent would have a real impact on people's living standards, he said. Mr Yang said the mainland should boost exports to counterbalance the rise of imports following its entry to the World Trade Organisation. It should strive for a trade surplus of at least US$20 billion (HK$155 billion) this year, he said.