Feature
THE UNDERWATER IMPACT The onus on shipping companies to reduce sulphur emissions has historically been lax. Cheap – but sulphurrich – fuel, and a conundrum over whose responsibility falls where when vessels enter international territory, has made emissions-monitoring tricky. But last year new global limits on ships’ emissions in and around ports were introduced to tackle air pollution. A team of Southampton researchers is part of a Europe-wide project to assess whether measures being taken by shipping companies to cut air pollution are working – both above and below water. The €8 million EMERGE (Evaluation, Control and Mitigation of the Environmental Impacts of Shipping Emissions) project is evaluating the effects of potential emission reduction solutions for shipping in Europe. As part of EMERGE, the team of environmental experts from Southampton, in partnership with a team from the University of Hertfordshire, is taking a close look at so-called ‘scrubber technology’. This is a method many cruise ships, tankers and larger marine vessels use to remove pollutants from the gases passing from their engines up exhaust funnels and into the air. However, the scrubber water from the exhaust system – which contains some of 18
the contaminants that would have been emitted into the air – is usually released into the sea. There is a big question mark over the impact this is having on delicate marine ecosystems. The Southampton researchers are recruiting a small team of sea urchins and mussels to find out. Ian Williams, Professor of Applied Environmental Science, and Malcolm Hudson, Associate Professor in Environmental Sciences, are leading Southampton’s involvement, working with Research Fellow Lina Zapata Restrepo, data scientist and spatial analyst Patrick Osborne, and a small team of Master’s students. Ian said: “It’s not widely known among the public that aviation and shipping emissions have historically been routinely excluded from all kinds of databases that capture emissions. This is because any emissions that occur outside national borders are deemed to have occurred in
international territory and nobody wants to take responsibility. The reality is that the total emissions we produce globally are hugely underestimated.” Large vessels use bunker fuel. “This is the gloopy, heavily-contaminated black sludge that is left when everything else – propane, butane, diesel, gasoline, even bitumen – has been taken out of the crude oil,” explained Ian. “Bunker fuel is full of sulphur and heavy metals, but it’s used for good reasons – it’s an effective use of material that would otherwise be waste, and it’s cheap.” Pollution problem Sulphur emissions at sea is one of the last remaining sulphur pollution problems to be tackled. Ian said: “Sulphur dioxide from fossil fuels on land was a terrible problem in the ‘60s, ‘70s and ‘80s, but we have addressed that by removing the sulphur from fuel. In the ‘70s, electricity generation from fossil fuels was legislated against, then in the ‘80s and ‘90s cars were addressed by removing lead from petrol and fitting catalytic converters. It’s taken 30 more years to address shipping, partly because of the lack of alternatives. The last remaining area where sulphur emissions are a problem is out at sea.” This is now being forced to change. From 1 January 2020, a new limit was imposed regarding sulphur dioxide and nitrogen oxide emissions close to port areas, known as Sulphur Emission Control Areas. The new global upper limit on the sulphur content of ships’ fuel has been reduced from 3.5 per cent to 0.5 per cent. “The legislation has focused on sulphur dioxide emissions because they are harmful
