The global economy is at risk of settling into a low-growth rut without urgent action to roll back recently erected obstacles to trade and greater investment in tackling climate change, the Organization for Economic Cooperation and Development said Thursday. In its quarterly report on the outlook for the global economy, the Paris-based research body said it continues to expect that world output of goods and services will increase this year at the slowest pace since the financial crisis. But it doesn’t now expect any pickup…