Climate Change Impacts: Ocean Warming and Acidification

Scientists are raising the alarm that warming and rising acidity of oceans is spelling ecological upheaval for marine ecosystems.

Time web news describes the demise of the coral reefs off of Florida. Everywhere, reefs are under pressure from rising sea temperatures, ocean acidification, coastal pollution and physical damage.

The interplay between ocean temperatures and acidification of these waters poses a threat to marine ecosystems across the globe. The rising proportion of carbon dioxide in our atmosphere, due to our addiction to fossil fuels, has led to an overall warming of the planet.

As the oceans warm they are able to absorb greater amounts of carbon dioxide from the atmosphere. Up to 50% of the CO2 released by burning fossil fuels over the past 200 years has been absorbed by world's oceans. This process increases the pH of the water, making our oceans more acidic.

Both, growing acidity and warming waters are impacting coral reefs and the basis of ocean food webs.

Indonesia's dying reefs

This summer the Wildlife Conservation Society released reports that indicate that a dramatic rise in the surface temperature in Indonesian waters has resulted in a large-scale bleaching of coral populations.

Subsequent monitoring conducted by marine ecologists from WCS, James Cook University (Australia), and Syiah Kuala University (Indonesia) were completed in early August and revealed one of the most rapid and severe coral mortality events ever recorded. The scientists found that 80 percent of some species have died since the initial assessment and more colonies are expected to die within the next few months.

According to the National Oceanic and Atmospheric Administration’s Coral Hotspots website, temperatures in the region peaked in late May of 2010, when the temperature reached 34 degrees Celsius — 4 degrees Celsius higher than long term averages for the area.

Similar mass bleaching events in 2010 have now been recorded in Sri Lanka, Thailand, Malaysia and many parts of Indonesia. While warming waters kill coral reefs, they also have another effect that is threatening all marine ecosystems.

Food web disrupted

The tiny organisms that form the base of the ocean food web, pteropods, build calcium carbonate shells. Increasingly, acidic oceans dissolve those shells and make it harder for these organisms to build them in the first place.

If you doubt the importance of these microscopic creatures, consider that they support the diet of zooplankton, Pacific salmon, mackerel, herring, cod and baleen whales. Key fisheries will be effected.

With threats to the base of any food web there is a domino effect. Which species will be the losers and which the winners?

Some species will likely benefit; some sea grasses, jellyfish and sponges may proliferate where before they were out-competed by other species.

Biodiversity threatened

Despite some species proliferating it's a fair bet that the diversity of marine life will take a huge hit as these food webs collapse. There are clear signs that increasing temperatures and increasing acidity will have dramatic effect on oceans in the next few decades if we don't curb our greenhouse gas emission today.

Canada's opportunity

In 2002, the World Parks Congress recommended that 20-30% of every habitat in the oceans be given full protection from extractive uses. These areas are known as no-take Marine Protected Areas (MPAs).

Less than 0.5% of Canada’s Oceans are protected in federally designated MPAs.

As a signatory to the United Nations Convention on Biological Diversity (CBD), Canada has a duty to uphold its commitment to establish and maintain a comprehensive, effectively managed and ecologically representative national system of MPAs.

In addition to increasing our percentage of protected marine wilderness, we must have a plan to quickly and effectively reduce our carbon dioxide emissions. To date the federal government has no credible plan to effectively reduce Canadian emissions in the next decades.

More Information:

Top 5 ways to get the government to confront the climate crisis - download pdf


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