For months, a withering drought has created major traffic jams at the Panama Canal. The drought, which may have been exacerbated by climate change, has left the canal’s water levels lower than ever, forcing Panama to let fewer ships through. The restrictions have led to delays, increased shipping costs, and uncertainty over the future of one of the world’s critical trade chokepoints. “This has fundamentally changed how shipping through the canal works,” said Soren Stokkebaek Andersen, a regional commercial manager at Leth Agencies, a shipping agency.