The Ocean Cleanup is due to begin clearing up the Great Pacific Garbage Patch in 2020. To get a better idea of what will be required, the Dutch foundation last year went for a close up look. It's now begun sizing up the task from the air and initial findings are that it's worse than originally thought.

"The Aerial Expedition - our final reconnaissance mission - brings us another step closer to the cleanup of the Great Pacific Garbage Patch," says CEO and founder of the Ocean Cleanup Boyan Slat. "The initial findings of the expeditions again underline the urgency to tackle the growing accumulation of plastic in the world's oceans."

Last year's Mega Expedition had already identified pieces of plastic measuring up to 0.5 m (1.5 ft) in span, as well as larger masses of plastic and large discarded fishing nets, otherwise known as "ghost nets," in which sealife can become tangled. The first Aerial Expedition flight is said to have revealed more debris than was expected to be found in the heart of the accumulation zone.

Details of the flight, which was the Ocean Cleanup's first reconnaissance flight over the Great Pacific Garbage Patch, were revealed yesterday. It comprised a number of low-speed and low-altitude passes back and forth along the northern boundary of the Patch between Hawaii and California in a modified C-130 Hercules aircraft.

Surveying in this way makes it possible to cover the same area that was was covered by the Mega Expedition every five minutes. The plane was kitted out with a variety of scanning equipment, including LiDAR and multispectral camera technology, and a number of observers on board were tasked with counting the pieces of debris they spotted. Over the course of two-and-a-half hours, more than a thousand items are said to have been counted.

The Aerial Expedition as a whole is aimed at developing an understanding of how much, what type and what size of debris there is, as well as giving an idea of how many "ghost nets" will have to be retrieved. This information is said to be crucial for the development and design of the eventual cleanup system, the logistics of transporting plastic back to land, the methods for recycling the plastic retrieved and and the costs of the cleanup.

The remaining Aerial Expedition flights are due to be completed this week, after which the data gathered will be combined with that from the Mega Expedition and published in a peer-reviewed scientific paper early next year.

View gallery - 9 images