Great Barrier Reef Has Lost Over 50 Percent of its Coral

MelbourneMore than half of the coral population of Australia-based The Great Barrier Reef has been depleted in the last three decades.

A team of researchers supervised by Dr. Andy Dietzel, from the ARC Center of Excellence for Coral Reef Studies (CoralCoE), released a statement saying that there are many studies on the changes in the structure of populations of humans, but not enough about coral populations. 'Our results show the ability of the Great Barrier Reef to recover - its resilience - is compromised compared to the past, because there are fewer babies, and fewer large breeding adults'. Branching and tablet-shaped corals, which provide habitats for several types of fish, were the worst affected by mass bleaching events in 2016 and 2017 (caused by record-breaking temperatures).

Image: Coral on Lady Elliot Island on the Great Barrier Reef in Queensland, Australia.

Findings published earlier this year show that widespread ecosystem collapse in the coming decades is possible, and the researchers pointed to the Great Barrier Reef as a prime candidate to die off if humanity doesn't get its act together.

The sizes of coral populations are also vital when it comes to corals' ability to reproduce.

The researchers found that better data on coral demographics is needed to understand how their populations are changing.

Back-to-back mass bleaching events in 2016 and 2017 prompted the government to downgrade the long-term outlook for the world's largest living organism to "very poor".

Mass bleaching was first seen on the reef in 1998 - at the time the hottest year on record.

Together with his co-authors, Dr. Dietzel evaluated coral communities and the size of their colony along the length of the Great Barrier Reef between 1995 and 2017.

Larger species, such as branching and table-shaped corals, have been affected hardest, nearly disappearing from the far northern reaches of the reef, which experienced extreme heat stress during 2016 and 2017. The UN report warned that even if global warming is limited to 2.7 degrees Fahrenheit, most of all tropical coral reefs on the planet will disappear.

They think the situation is now urgent, saying: "There is no time to lose - we must sharply decrease greenhouse gas emissions ASAP".

We found the number of small, medium and large corals on the Great Barrier Reef has declined by more than 50 percent since the 1990s.

A 2018 United Nations report on the impact of global warming of 1.5C above pre-industrial levels found that up to 90 percent of coral reefs would be lost by 2050.

Coral reefs - which harbor the highest biodiversity of any ecosystem on earth - are some of the most vulnerable environments to the climate crisis.