Last week, CO2 concentration above Mauna Loa reached 400 ppm for the first time since continuous records commenced in 1958.  The long-term trend since 1958 is becoming steeper (the rate of increase is growing). Atmospheric CO2 was last at this level over 3 million years ago, well before Homo sapiens evolved.

Growing atmospheric concentrations of CO2 lead to warming, and to ocean acidification.  Ocean surface  temperatures have warmed measurably since the start of industrialization, and pH of surface waters is declining at a rate which appears to be more rapid than at any time in the last 450 million years.  pH was virtually unchanged throughout the last 10,000 years, but has fallen 0.1 pH unit since start of industrialization, and is expected to fall as much as 0.7 pH units over the next couple of centuries if we do not wean our economies off fossil fuels (Zeebe 2012).

There are already studies showing effects of reduced pH on growth of some corals, as well as studies showing deleterious effects on a range of other marine species.  Bleaching due to warming has had significant impacts on coral cover on reefs worldwide, although mass bleaching was unknown until first described by Peter Glynn in Panama and Galapagos in the early 1980s. Bleaching-caused mortality and acidification-cause slowed growth act in consort to further reduce the status of coral reefs (many of which are already severely degraded by overfishing, pollution and inappropriate coastal development).  Live coral cover in shallow regions (~10m depth) of the Great Barrier Reef has declined by 50% over the past 27 years, due partly to bleaching losses.  Data for the Caribbean are less robust, but tell an equally or more depressing tale.

This week, the Prime Minister of Canada, Stephen Harper, will journey to New York to give a speech in which he will extoll the value to the United States of building the Keystone XL pipeline (jobs and oil for USA), while also claiming a strong commitment by his government to the environment. That commitment is hard to discern.  Tar sands oil extraction is by far the most polluting form of oil production around, both in CO2 emissions and in other forms of pollution (chiefly heavy metals in waterways). Canada is third, globally, in its per capita emissions of CO2.  The Harper government pulled Canada out of Kyoto, has no plan to achieve its own (weak) target for emissions reductions by 2020, and still has not put in
place emissions regulations for the tar sands industry.  This government is also the one that keeps getting written up in Science and Nature for its anti-science agenda.

True, not building Keystone XL will only slow, not stop, Canada’s tar sands industry.  and Canada’s total emissions of CO2 are a tiny percentage of the world total.  But as someone who would like coral reefs to persist, I think we have to start somewhere if we are going to change our ways. Stopping one pipeline is one small step on a long road to save coral reefs.  Some things in life are more important than the bottom line.

Peter Sale

www.uwindsor.ca/sale           www.petersalebooks.com
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