When a cargo ship blocked the Suez canal for nearly a week, the eyes of the media focussed on shipping. Hundreds of vessels were stuck as tailbacks built up at the entrance to what is one of the world's busiest trade routes. What effect does the sheer quantity of goods which we routinely move around the globe have on the environment? Are there ways of 'greening' shipping and lessening its environmental impact? In this programme, Lucy Siegle chairs a panel discussion which aims to find out. Producer: Emma Campbell