Place chart

‘The world’s most polluted island’ is charted in the wrong place, says Britain’s Royal Navy

Britain’s Royal Navy has discovered that Henderson Island, a remote and uninhabited island in the Pacific Ocean, has been misplaced on charts for 85 years. After arriving in the area, HMS Spey informed authorities that the island was actually a mile south of where it is shown on nautical charts used by sailors since 1937.

Far out in the Pacific Ocean, Henderson Island lies 3,600 miles (5,800 kilometers) west of Chile and holds the earth-shattering title of “the most polluted island in the world.” With an astonishing 270 objects washing up on its shore every day, the beaches of Henderson Island are littered with man-made pollution.

The Navy uses digital charts, as do many other ships that cross the open oceans. However, while they’re incredibly accurate for often-surveyed areas, areas such as the Pitcairn Islands (which sit almost directly in the middle of the world’s largest ocean) rely on satellite data to pinpoint their exact locations.

It was pointed out that the data for some of these islands might not be accurate, and HMS Spey, which was in the area, offered to help. HMS Spey is not a survey vessel – it is in fact a River-class offshore patrol vessel – but using radar and navigational data, it cross-referenced the actual location of Henderson Island and identified the error in the current maps.

“In theory, the image returned by the radar should be exactly over the mapped feature – in this case, Henderson Island,” Lt. Michael Royle explained in a declaration.

“I found out that was not the case – the radar overlay was one mile from the island, meaning the island was plotted in the wrong position when the map was first produced. Notes on the map indicate that it was made in 1937 from aerial photographs, implying that the aircraft that took the photos was slightly off in its navigation calculations.

The actual location overlaid on the originally mapped location. Image credit: The Royal Navy

The error was identified Thursday evening and has since been updated.

Henderson Island is relatively small at just 14.4 square miles (37.3 square kilometers), but is home to around 40 million pieces of plastic. Likely due to incoming currents and its positioning in the middle of the Pacific, floating plastic is accumulating in the area at a staggering rate. Scientists are now looking to learn more about the isolated area and humanity’s impact on it, and have collected water samples.

‘Scientists in the UK have very little data on the ocean in this region – its salinity, temperature, water pressure etc.,’ Lt Royle continued.

“They are keen to understand climate change in the region.”