Thanks to the work of oceanic gyres, all the plastic waste we throw into the sea (between 4.8 and 12.7 million tons annually) does not float about with an equal distribution. Instead, powerful currents suck it all together, creating what are informally known as ‘the world’s largest rubbish dumps’ – enormous great piles of waste (predominantly plastic) found floating around in the centre of the world’s main oceans.
But how big exactly are these dumps? That was the answer that researchers at The Ocean Cleanup – an enterprise famously founded in 2013 by Boyan Slat when he was just a teenager (see video below) – wished to answer. Their aim is to clean up the ‘Great Pacific Garbage Patch’ – an enormous gyre of waste floating across the North Pacific between Hawaii and California, by ‘designing a network of extremely long floating barriers that will remain stationary in the water, enabling the ocean to concentrate the plastic using its own currents.’
With this in mind, they recently undertook an ‘Aerial Expedition’, a series of low-speed, low-altitude flights across the patch to get a more accurate sense of how large it really is.
‘The reason [we] started the initiative of the Aerial Expedition,’ explains Joost Dubois, a spokesperson for The Ocean Cleanup, ‘is because our experience of the Mega Expedition, where we mainly carried out surface-based surveying of the area [using 30 vessels in August 2015], came to the conclusion that we probably underestimated the presence of large debris. To come to a statistically relevant estimate, we needed to expand the surface area surveyed, which could only be done from a plane.’
Using ‘expert spotters and an experimental array of plastic scanning equipment’ aboard a modified C-130 Hercules aircraft, the survey was capable of registering plastic of 50cm diameter and larger, with over 1,000 items counted during a two-and-a-half-hour flight. The expedition is claimed to be the first-ever reconnaissance flight over the patch. While final results are yet to be published, the survey – which covered an estimated 300 square miles (777km2) – enforced the conclusions formed during the previous ‘Mega Expedition’ that the patch is significantly larger than previously believed. Establishing a firm number for the total mass of plastic trash in the Great Pacific Garbage Patch is essential to the success of this immensely large-scale project, scheduled for full deployment in 2020. It’s a project Dubois describes as ‘the largest cleanup in history’.
‘We do our ocean plastic research – of which the Aerial Expedition is a part – in order to know what we are up against in the cleanup,’ he continues. ‘How much plastic is there, where [it is] and how it is moving through the gyre, at what depths in the water, how big are the parts, and what is the chemical consistence of the materials – all these are very relevant for us to decide on dimension, locations and logistics of the final cleanup.’