Coral reefs are hotspots for ocean biodiversity. They are also very sensitive to humankind's uncontrolled 'carbon dioxide enhancement' experiment, both through the warmer sea surface temperatures (and colder, too!) wrought by global warming and as well as increasing dissolved CO2-content leading to ocean acidification. As such, the health (status) of the reefs serves as an early warning for the effects of climate change.
Unfortunately, the news is grim. Corals in Australia, Indonesia and SE Asia are disappearing faster than expected. "We have already lost half of the world's reef-building corals," said John Bruno, lead study author. For humans, it's another suggestion -- like the melting Arctic or increases in dangerous wildfire weather-- that the climate is changing at a faster pace than expected. Put another way, the climate models our current projections are based on may be too conservative.
Understanding exactly what this alarm means is an important endeavor. We are still learning about how coral reefs work. Important questions being asked are “why coral reefs bleach and die, how they respond to climate change – and how that might affect humanity”. The “engines of the reef” -- microscopic algae that feed the coral – are having their genetics investigated to better understand their role in coral bleaching. Given coral's survival through geologic time, it obviously has some survival mechanisms to resist the impacts of climate change. Ancient corals are being examined to determine what these mechanisms are, with the hope that modern corals can survive ocean acidification.
In addition to the overarching ecological impacts, loss or damage to coral reefs can also have an economic impact as well. The Great Barrier Reef in Australia provides a $A6 billion dollar a year industry, another incentive to preserve the reefs and prevent climate change. While climate change is the main threat, other dangers also exist for the reefs of the world. Agricultural pesticides are so poisonous that they can prevent coral spawning, and consequently the reef's ability to regenerate and protect itself. Fertilizer runoff can also promote algal growth, blocking sunlight and killing reefs.
The human impact on the environment is obvious – for example, climate change, land degradation and pollution. It is time to act to minimize that impact. The militant consumerism of current (primarily Western) society is ecologically destructive and socially divisive; it is time to re-imagine society into something environmentally sustainable and mutually inclusive. It is not an easy path, but the alternatives are even less appealing.