The Great Barrier Reef is experiencing a massive bleaching event due to a spike in water temperature — about 1.8 to 3.6 degrees Fahrenheit higher than normal.

The worst damage is happening off of Australia’s northern coast, where corals are experiencing a 50 percent mortality rate, prompting the Marine Park Authority to raise the coral bleaching threat to its highest level on Sunday.

“Corals were effectively bathed in warm water for months, creating heat stress they could no longer cope with,” Great Barrier Reef Marine Park Authority Chairman Dr. Russel Reichelt said in a statement.

“A level three response means we’re stepping up surveys in response to the coral mortality to help us better understand the effects of various pressures on the Reef and help guide environmental actions, ” Reichelt said.

Studying the many stressors of coral reefs is necessary, but it is not enough argues Steven Miles, Queensland’s environment minister. His Australian counterpart Greg Hunt has announced plans for more monitoring programs for run-off pollution and crown-of-thorns starfish outbreaks but has remained silent on climate change. “Where is his plan to reduce Australia’s greenhouse gas pollution?” Miles asked in an interview with The Guardian.

Queensland Greens senator Larissa Walter echoes Miles’ sentiment: “Increased monitoring is important but if we continue to open new coal mines the monitoring results will only get worse and worse.”

The severity of the bleaching event has moved environmental groups like WWF to urge the government to prevent further damage to the World Heritage site. “The reef can recover but we must speed up the shift to clean, renewable energy,” said WWF spokesperson Richard Leck.

Corals can survive mild bleaching events, but the periods of extreme heat are getting longer and hotter. According to NOAA, we are currently in the middle of a third global bleaching event, which is also the longest on record (it started in 2014).

Don't want to believe it? Check out the alarming footage below, released by WWF-Australia.