By Richard Lockhart in Edinburgh The explosions on September 25 at the Nord Stream 1 and 2 pipelines in the Baltic Sea off the Swedish and Danish coasts could create a climate catastrophe that is just beginning to be realised, although it offers rare opportunities to measure the exact impact of methane emissions on the environment. Already dubbed the worst methane leak ever, the three explosions, which created three holes in the two systems, which each consist of two pipes, have released about 300,000 tonnes of methane, causing a 700-metre-wide pool of bubbling water in the Baltic Sea. The exp…