Climate change has become a significant political issue as serious negative effects continue to manifest worldwide.
One facet of this is the changes in the world’s oceans which have triggered a cascade of social, economic, and environmental consequences. Coastal ecosystems, for example, are degrading at unprecedented rates, particularly coral reefs.
Coral reefs are, in many ways, the marine equivalent of rainforests and are one of the most productive and biodiverse ecosystems on Earth. A particular region, known as the Coral Triangle, is the richest centre of marine life and coral diversity on the planet.
Stretching across Indonesia, Malaysia, the Philippines, Papua New Guinea, Timor-Leste, and the Solomon Islands, this region occupies just 1.5 % of our oceans, yet it represents 30 % of the world’s coral reefs. It not only harbours a staggering number of corals but also more than 2,000 species of fish. Aside from its biodiversity’s value, the Coral Triangle’s commercial importance is massive. One example would be its role as a spawning area and nursery for large populations of commercially fished tuna.
As a member of the Coral Triangle, Malaysia has a direct stake in the health of tropical coral reefs. Currently, coral reef ecosystems in Malaysian waters are thought to be under pressure mostly due to local stressors (e.g. cyanide fishing, marine mining operations, silt and sedimentation, nitrate and phosphate pollution) as opposed to global stressors like rising sea temperatures.
However, it is a matter of time before Malaysian coral reefs will also experience the type of coral mass bleaching that has occurred multiple times in the last five years in the Great Barrier Reef, Australia, and there is an urgent need to plan for this eventuality.
Most of our information on temperature-driven mass coral bleaching comes from work done in Australia on the recent Great Barrier Reef mass bleaching events in 2016, 2017, and 2020. This has been due to both the fact that Australia has the largest continuous coral reef system in the world, as well as the resources and dedicated work of multiple research institutes in Australia coordinating together to detect large-scale events and trends affecting the GBR.
It is important to put a recent report on the health of the corals of the Great Barrier Reef into context. The GBR has been carefully monitored by the Australian Institute of Marine Science (AIMS) annually since 1987. This unparallel record of environmental health collected from multiple and more or less consistent regions across the length of the GBR gives us the best indication we have of the general “natural” state of coral reefs globally. As such, just as the major GBR mass bleaching events of 2016, 2017 and 2020 can be mostly attributed to warmer than average sea surface temperatures, we can be reasonably assured that the good news reported this year is that the Northern and Central sections of the GBR have recorded the highest coral cover in the history of AIMS’ monitoring program is proof that coral ecosystems still have significant capacity for self-restoration if adverse conditions do not occur (2021-2022 is a La Nina year, cooling down temperatures).
To be specific, the coral cover of the Northern and Central GBR has increased to 36% and 33%, respectively, in both cases, these numbers represent more than a two-fold increase in coral cover since 2019. However, this increase in coral cover hides a worrying trend, which is that the rise in coral cover is driven by faster-growing coral species, such as Acropora. This is ecologically analogous to the formation of secondary forests on land after the original forest ecosystem is removed; while vegetation has technically returned to previously devastated lands, the original biodiversity and eco-structure of the area will take years or decades to fully recover, if at all. As climate conditions worsen, these biodiversity-poor regrowth areas may succumb even faster when challenged with ever-rising ocean temperatures.
The coral ecosystem has the dubious distinction of being the proverbial “canary in the ecosystem coalmine”, as probably the first ecosystem predicted to collapse globally due to indirect human action via climate change. It is currently difficult to describe the true state of the overall Coral Triangle but what we do know is that the collapse of coral ecosystems on a global scale by 2100 is likely even if we stabilize overall global warming to 2 °C. At this moment, with current CO2 (carbon dioxide) emission trends, we are headed towards 2.5 °C of warming by 2100.
While the collapse of global coral ecosystems will not be as dramatic for most people as the destruction of tropical rainforests or the mass failure of food crops from bad weather, it is important for governments and policymakers to at the very least put in place the framework to implement some of the required changes our societal and economic systems will need to make to adapt to this ecological change now while there is still time.
Whilst we should all work for, and hope for, the best in terms of curtailing CO2 emissions and halting further climate change, it should be appreciated by all that these changes are no longer predictions of the far future. If carbon emissions are not curtailed, and the lessons learnt from dealing with the collapse of coral reef ecosystems will soon become increasingly relevant to handling another climate change-mediated collapsing ecosystems on land.
By Dr Chen Jit Ern, Head – Jeffrey Sachs Centre on Sustainable Development, Sunway University
