Record water temperatures have led to more and more mass bleaching events along the Great Barrier Reef. Experts warn the reef is running out of time.

Water temperatures along the Great Barrier Reef off the northeast coast of Australia have hit a 400-year high, according to a major new study, which concludes that human-induced climate change is the most likely cause.

Using coral samples to reconstruct sea temperatures dating back as far as the 17th century, scientists found that temperatures before 1900 had been relatively stable, but that they had been increasing on average by 0.12 degrees Celsius (0.2 degrees Fahrenheit) per year since 1960.

“These are corals that have lived for 400 years and these are the warmest temperatures they’ve experienced,” said Helen McGregor, co-author of the study which was published in the science journal Nature in Australia on Thursday.