The projection comes from the International Labour Organistation (ILO), which said its figure for the losses included actual and prospective positions that would have been eliminated worldwide.
Economic growth has to be revived in Asia and developing countries to reverse the trend, which has been fuelled by "fear and insecurity" since 11 September, the ILO said.
Separately, the Geneva-based body said the airline industry, in particular, will take years to recover after more 200,000 of its 4 million global employees lost their jobs after the attacks.
"The overall picture would mean very little improvement in the global employment situation," it said.
Poor outlook
The ILO report warned the 1.7% average annual growth of the world's workforce over the past decade had outstripped the 1.4% annual rise in global employment.
"In recent years the global economy has created about 40 million jobs a year for the 48 million annual new entrants to the labour force," it said.
Over 97% of new job seekers in the next decade will come from developing countries, with 65% of them in Asia, the report predicted.
For the industrialised world, the ILO forecast the labour force would shrink, with population growth expected only in the US.
Globally unemployment rates are expected to remain stable but the number of working poor will rise, the ILO said.
More than one billion people live on less than one dollar a day, according to UN estimates.
The reports were released ahead of the ILO's Global Employment Forum in Geneva of business leaders and politicians, which will discuss reviving economic growth.