In 2019, Alan Ladd, a marine engineer, was on a cruise ship that was slowing down to give passengers a better view of the Hubbard Glacier – the largest tidewater glacier in North America. Briefly looking away from the harbour seals and orcas, Ladd noticed a stream of black grease, with a rainbow sheen, bubbling to the surface of the water.
“The only reason I saw it was because the vessel had stopped. All of a sudden I could see this pollutant and this soot,” says Ladd, who works with Alaska’s Ocean Ranger programme as one of several independent observers of effluent from shipping. “The thing that really disturbed me more than anything is they didn’t do anything about it.”