great barrier reef bleaching

In my previous post I briefly mentioned the most recent bleaching of the Great Barrier Reef.

A few people reached out and asked what that actually means. Happy to give you more details on this. Firstly, it’s not good news at all.

Corals are thermally sensitive, meaning that they can only tolerate small temperature ranges. However, climate change is causing abnormally high sea-surface temperatures, which is causing corals to bleach during summer months. The intensity of coral bleaching increases as temperatures become hotter.

Zooxanthellae are tiny, colourful marine algae, which live inside corals, providing them with much of their colour and, most importantly, their primary supply of energy. However, if the surrounding sea temperature becomes too warm, the algae die.

The loss of these zooxanthellae is what is referred to as ‘coral bleaching’.

Why are corals so important other than that they are nice to look at? Healthy coral reefs are among the most biologically diverse and economically valuable ecosystems on earth, providing valuable and vital ecosystem services. Coral ecosystems are a source of food for millions; protect coastlines from storms and erosion; provide habitat, spawning and nursery grounds for economically important fish species; provide jobs and income to local economies from fishing, recreation, and tourism; are a source of new medicines, and are hotspots of marine biodiversity.

This year, the Great Barrier Reef — the world’s largest reef system, spanning more than 344,400 square kilometers — suffered its third major bleaching event in the last five years. Previous ones took place in 2016 and 2017, with the 2016 event considered the most severe.

However, this year’s bleaching is proving to be the most extensive. A group of researchers has just updated the latest 5 year projection for the Great Barrier Reef from poor to very poor.

There’s really no time to lose to reduce greenhouse gas emissions and the Australian government is not pulling its weight in that regard. Which is quite astonishing in itself as 70% Australia’s GDP is coming from the services sector within which tourism is a large proportion.

Weird, don’t you think?

Let me know in the comments what you think.

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