OCEANS RISING

They may be deep and wide, but the world’s oceans are bearing a heavy load: they absorb one third of the carbon produced by human industry. As a result they’re turning into acidic bathtubs. As water warms, it expands, hence the rising sea levels.

WARMER OCEANS, HIGHER SEA LEVELS 

Our oceans cover 70% of the earth’s surface and store 1000 times more heat than our atmosphere.¹ In short, oceans play a crucial role in determining the way our weather patterns work, and how climates have remained relatively stable in all parts of the world for centuries.

But the oceans are changing. They’re getting warmer. In the past fifty years, our oceans have increased by .037° in temperature, and that heat has increased to depths of 3000 metres.² That’s enough to bleach coral reefs all over the world, turning them from thriving underwater ecosystems into depleted wastelands.

Since the early '60s, the ocean has absorbed 80% of the heat added to the climate, causing sea levels to rise. Over the next 100 years, the IPCC predicts a rise in sea levels between 18 and 59 centimetres.³ In fact, world sea levels could increase by as much as one metre by the end of this century if greenhouse gas levels do not recede. By the 2080s, millions and millions of people will be affected by flooding every year because of rising water. Coastlines and beaches will erode. Everything that lies on a coastline—whether it's a small village in Bangladesh or a metropolis like New York City—will become more vulnerable to storm surges, flooding, and even to eventual engulfment.  How can we ignore climate change when more than half of the world’s twenty largest cities are on the coast, and one-third of the world’s population lives within 100 kilometres of our oceans? The IPCC hasn't ruled out some pretty scary potentials. If the Greenland ice sheet melts even partially, and some of the West Antarctic ice sheet goes too, we're looking at a rise in sea levels of four to six metres or more.

All this activity will wreak havoc on our weather. Patterns governed in large part by ocean currents will become seriously unstable. Ocean currents circulate nutrients, oxygen and heat around the globe via a system known as the Ocean Conveyor. The conveyor is propelled by a) salinity and b) cold temperatures from the polar region, and the mix of salt and fresh water moderates temperature extremes around the globe, keeping the Arctic cold, Europe temperate, and the equator hot. But changes in long-established patterns are altering the salinity and freshwater content of the ocean. Some regions are becoming saltier, others contain more freshwater than they used to. What’s at risk? The Gulf Stream—a warm current that essentially gives Europe its temperate climate despite being on the same latitude as chilly, northern Quebec—could become diluted, affecting the North Atlantic fisheries and altering Europe's temperate climate.

^{1 Source: http://www.oceansalive.org/explore.cfm?subnav=article&contentID=4711
2 Source: IPCC WGI Fourth Assessment Report: p.4.
3 Source: Ibid.}