Imagine all the colour and vibrancy of coral reefs fading away into fuzzy, crumbling greys and browns, and you're left with a coral graveyard that could become the norm. I've been privileged to see many of the world's finest and least disturbed reefs. Mine were the first human eyes to see many of the remotest reefs at a time when we really could describe them as pristine. I would never have dreamed that they were at risk from people, far less than from something as remote then as climate change. Today, despite the doom and gloom one reads so much about, one can still find reefs that are vibrant, thriving ecosystems. But sadly, too, there are more and more that look like something from the dark side of the Moon. These degraded reefs have been ravaged by destructive fishing, bad land use practices that smother them with silt, and pollutants that foster disease and overgrowth by seaweeds. More alarmingly, there are large areas that are killed off and degraded by warming seas linked to climate change. We've all read that global warming poses a tremendous threat to our planet, and that coral reefs will face an uphill battle to survive in warmer waters. Yet the greatest threat to our oceans and to all of its wonders is little known, nearly impossible to see, and potentially devastating. This is not climate change, but does stem from the excess carbon dioxide emissions that contribute to climate change.
Changing chemistry
The
ocean absorbs about one-third of the CO2 entering the atmosphere - a
natural process that for millennia has maintained the carbon balance of
our planet.
In recent times we have upset this balance; global
CO2 emissions are at an all-time high, and our oceans are absorbing
more CO2 and at faster rates than ever before, causing a shift toward
greater acidity.
This removes carbonate from the water; and
carbonate is an essential building block for calcifying organisms, like
corals, molluscs, sea urchins and many other important creatures that
live on reefs or help to build them.
Too much carbonic acid
lowers the natural pH balance of the oceans, causing acidification,
which wreaks havoc on marine habitats and species.
Just imagine
all the colour and vibrancy of coral reefs fading away into fuzzy,
crumbling greys and browns, and you're left with a coral graveyard that
could become the norm if we don't address the threats to our oceans.
We need to find ways to convince people to take action, but that is a major challenge. Given
the difficulties that many coral reef managers around the world have in
controlling such pressing direct threats as destructive fishing,
overfishing and pollution, they are understandably hesitant about
taking on an issue that they feel is beyond their ability and mandate
to tackle.
Climate change is often seen as too daunting and too global for them to address, and too abstract for them to communicate. Fortunately,
in some respects, the sudden and startling onset of mass coral
bleaching linked to warming seas has changed that a little.
We
have developed and are applying some straightforward, practical actions
to design marine protected networks and zone the individual sites to
protect areas that are naturally resistant to bleaching.
These
areas are key, as they provide larvae that are transported to more
vulnerable reefs where they settle and enhance recovery.
The
high visibility of coral bleaching makes this relatively easy to see
and study, but ocean acidification is difficult to detect by sight
alone.
It is creeping, progressive, and insidious - likened by
some scientists to osteoporosis of the reef - a weakening of the reef
structure that makes corals more vulnerable to breakage from waves and
human use.
We simply do not know yet whether we have reached or surpassed the point of no return for some coral species.
If current emission trends continue, we could see a doubling of atmospheric CO2 in as little as 50 years.
This
would lead to an unprecedented acidification of our oceans that coral
reefs would be unlikely to survive, a scenario that should spur us into
action to try and find solutions.
A significant lowering of
ocean pH would mean potentially massive coral loss. That would lead to
the death of countless marine species as well as the devastation of
economies dependent on ocean health and productivity.
'Meeting of minds'
It would also mean the end of an era for coral reef and scuba diving aficionados around the world.
But,
more importantly, it would remove the livelihoods of hundreds of
millions of people around the globe who depend on reefs for food,
income, coastal protection and stability.
Current estimates
predict that we could lose all coral reefs by the end of the century -
or, in the worst case scenario, possibly decades sooner, if we don't
take action now to prevent ocean acidification.
Diseased coral
We have to maintain hope and optimism and keep trying to find solutions.
The
Nature Conservancy recently convened leading climate change experts,
top marine scientists, and prominent coral reef managers from around
the globe for a "meeting of the minds" session to chart a course of
action for addressing ocean acidification.
The key findings and
recommendations from this gathering were compiled into the Honolulu
Declaration on Ocean Acidification and Reef Management.
The most
logical, long-term solution to ocean acidification impacts is to
stabilise atmospheric CO2 by reducing emissions around the globe.
Yet
the Honolulu Declaration also outlines tangible steps that can be taken
now to increase the survival of coral reefs in an acidifying ocean,
while also working to limit CO2 emissions.
For example, we need
to identify and protect reefs that are less vulnerable to ocean
acidification, either because of good flushing by oceanic water or
biogeochemical processes that alter the water chemistry, making it more
alkaline and better able to buffer acidification.
We can achieve this protection by designating additional "marine protected areas" and revising marine zoning plans. We
also need to integrate the management of these areas with reform of
land uses that generate organic wastes and effluents that contribute to
acidification.
At the local level, we may need to restrict
access to more fragile coral communities or limit it to designated
trails, much as we do with trails through sensitive environments on
land. We should consider designating "sacrificial" reefs or parts of reefs for diver training and heavy visitor use.
Another
intriguing option is the prospect of farming local corals that prove
more resistant to acidification, and "planting" them in place of those
that weaken and break apart. The consequences of inaction are too depressing to contemplate.
Global
leaders, reef managers, and citizens around the globe should give all
the support they can to the Honolulu Declaration to ensure the survival
of the beauty and benefits of our marine treasure trove for future
generations.
Source: BBC News
Dr Rod Salm is director of The Nature Conservancy's Tropical Marine Conservation Program in the Asia-Pacific region
The Green Room is a series of opinion articles on environmental topics running weekly on the BBC News website
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3.21 Copyright (C) 2007 Alain Georgette / Copyright (C) 2006 Frantisek Hliva. All rights reserved."-----
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The Chapters Climate, Renewable Energy & Transport Recipe for rescuing our reefs
The Chapters Climate, Renewable Energy & Transport Recipe for rescuing our reefs 
