Climate Change

What is Happening in Our Ocean?

Carbon dioxide (CO₂) is a by-product of burning fossil fuels. CO₂has been identified as the largest single source of greenhouse gases.

Climate change has been identified as one of the greatest challenges facing humanity. The impacts of climate change are far from understood but the scientific consensus is that we need to act now to reduce our carbon emissions in order to halt the dramatic changes the future holds.

Oceans are a long term carbon sink for our planet and play an integral role in the Earth’s carbon cycle. The carbon cycle is the movement of carbon atoms through all things on the planet: the atmosphere, living and non-living organic material, oceans, sediments (including fossil fuels) and the Earth’s core. Due to the burning of fossil fuels, carbon in the form of carbon dioxide in our atmosphere has dramatically increased – a major contributor to the greenhouse effect. Through natural cycling processes, roughly half of the carbon dioxide (CO₂) released by human activities between 1800 and 1994 is now stored in the ocean. About 30 percent of modern CO₂ emissions released to the atmosphere are taken up by oceans.

Oceans also play a significant role in regulating the global climate and moderating weather systems. Changes in climate can have a profound impact on the functioning of ocean and coastal ecosystems.

Some anticipated impacts include:

sea level rise may result in increases in coastal flooding, storm intensity, and potentially changing current patterns
ocean warming may result in increased coral bleaching and mortality, stratification, changed circulation patterns of ocean currents, decreased amount of sea ice, possible pole-ward migrations of species and increased algal blooms
ocean acidification poses adverse effects on calcifying species such as corals, echinoderms, crustaceans, and mollusks as well as certain phytoplankton

Chain Reaction?

A phytoplankton bloom off the coast of Vancouver Island seen from space. Phytoplankton are responsible for much of the oxygen in the Earth's atmosphere – half of the total amount produced by all plant life.

Changes in wind velocity and extreme wind events will affect ocean circulation. This, in turn, alters how nutrients are brought from the ocean depths to feed microscopic ocean plants called phytoplankton. Phytoplankton breathe in CO₂ and release oxygen during photosynthesis, supplying 30 to 50 percent of the world’s oxygen. Shifts in the levels and location of nutrient upwellings could affect the amount and the location of phytoplankton. The tiny organisms are also at the base of the ocean food web and without phytoplankton, salmon and many other species would be compromised. This is one example of how integrated the ocean environment is and the level of impact one effect can have. Unfortunately there is little information available on ecosystem responses to climate change.

The United Nations appointed panel of experts, the Intergovernmental Panel on Climate Change (IPCC), completed its Fourth Assessment Report, and concluded that most of the warming observed over the last 50 years is attributable to human activities and that a further warming of the atmosphere by 1 to 6 degrees Celsius is expected.

We now risk serious harm to marine ecosystems with far-reaching consequences for human health and welfare. Maintaining the health of the oceans is increasingly important as we face the drastic challenges associated with rising CO₂ levels and a warming climate.

Changes are rapid, emphasizing the need for tracking and modeling systems that provide accurate and useful information. Adaptive management strategies could be an essential part of adjusting to climate change and the changes it will bring to our ocean ecosystems.