Climate change, reefs and the Coral Triangle

Without action on climate change, coral reefs in the Coral Triangle will disappear by 2100, the ability of the region’s coastal environments to feed people will decline by 80%, and the livelihoods of around 100 million people will have been lost or severely impacted.
More than 85% of reefs in the Coral Triangle are directly threatened by local human activities, substantially more than the global average of 60%.
- Find out more from Reefs at Risk revisited in the Coral Triangle [World Resources Institute website]

Impacts of climate change in the Coral Triangle

Climate change in the Coral Triangle is already having  a big impact on coastal ecosystems by warming, acidifying and rising seas. Coral Triangle reefs have experienced severe mass coral bleaching and mortality events  as temperatures have periodically soared.

The annual, maximum and minimum temperatures of the oceans surrounding the coastal areas of the Coral Triangle are warming significantly (0.09-0.12 ° C per decade) and are projected to increase by 1-4°C toward the end of this century.

Increases of more than 2°C will eliminate most coral-dominated reef systems.

These splendid reef systems will disappear if these events continue to increase in intensity and frequency.

Climate change impacts overview:
  • Coral Triangle seas will be warmer by 1-4°C
  • Acidic seas will drive reef collapse
  • Longer and more intense floods and droughts
  • Sea level rise of 0.5, 1.0 or 6 metres
  • More intense cyclones and typhoons
  • More annual climate variability in the Coral Triangle
     

Important habitats under threat

Climate change is also threatening coastal mangroves within the Coral Triangle, which are highly sensitive to rising sea levels. A multitude of other changes are destabilising critically important ecosystems along the coasts.

Stresses arising from climate change are also amplifying the impacts of
local stresses, leading to an accelerated deterioration of coastal ecosystems.

But there is some natural resistance

While coastal ecosystems are facing enormous pressures from both local and global factors, many areas within ecological resilience and are therefore among the most likely to survive the challenging times ahead.

High levels  of biodiversity, coupled with fast rates of growth and recovery, put many  Coral Triangle ecosystems in a favourable position to survive climate change.

Some parts of the Coral Triangle may have inherently slower rates of change in sea temperature and acidity, representing a potential refuge in an otherwise rapidly changing world.

What needs to be done

Stabilising atmospheric carbon dioxide at or below 450 parts per million (ppm) is absolutely essential if Coral Triangle countries are to meet their objective of retaining coastal ecosystems and allowing people to prosper in the coastal areas of the Coral Triangle.

However, climate changes in the Coral Triangle ecosystems are inevitable due to the lag effects of on coastal and marine systems and  associated terrestrial habitats.

What WWF is doing about climate change impacts in the Coral Triangle?
 / ©: WWF / Ove Hoegh-Guldberg
Aragonite - showing areas suitable for coral reef formation relative to atmospheric CO2 concentrations.
© WWF / Ove Hoegh-Guldberg
Coral bleaching due to temperature rise, Indo-Pacific Ocean. / ©: WWF-Canon / Jürgen FREUND
Coral bleaching due to temperature rise, Indo-Pacific Ocean.
© WWF-Canon / Jürgen FREUND
  • The Coral Triangle, just one per cent of the earth’s surface, includes 30%of the world’s coral reefs, 76% of its reef building coral species and more than 35% of its coral reef fish species as well as vital spawning grounds for other economically important fish such as tuna. It sustains the lives of more than 100 million people.
    More Coral Triangle facts
     

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