World trade will expand by just 1.7%, well below the April forecast of 2.8%, according to the latest WTO estimates.
The forecast for 2017 has also been revised, with trade now expected to grow between 1.8% and 3.1%, down from 3.6% previously.
With expected global GDP growth of 2.2% in 2016, this year would mark the slowest pace of trade and output growth since the financial crisis of 2009.
The downgrade follows a sharper than expected decline in merchandise trade volumes in the first quarter (-1.1% quarter-on-quarter, as measured by the average of seasonally-adjusted exports and imports) and a smaller than anticipated rebound in the second quarter (+0.3%).
"The dramatic slowing of trade growth is serious and should serve as a wake-up call,” said WTO Director-General Roberto Azevêdo. “It is particularly concerning in the context of growing anti-globalization sentiment. We need to make sure that this does not translate into misguided policies that could make the situation much worse, not only from the perspective of trade but also for job creation and economic growth and development which are so closely linked to an open trading system.
"While the benefits of trade are clear, it is also clear that they need to be shared more widely. We should seek to build a more inclusive trading system that goes further to support poorer countries to take part and benefit, as well as entrepreneurs, small companies, and marginalized groups in all economies. This is a moment to heed the lessons of history and re-commit to openness in trade, which can help to spur economic growth."