Ocean Mist

Issues and trends shaping our environment, health and economy

4 Oct 2013

A changing climate = less sustainability

Posted by Michael Keating

The latest report from the Intergovernmental Panel on Climate Change (IPCC) is another signal that we are on a dangerous track away from sustainability.

Climate Change 2013: the Physical Science Basis, says human actions have driven atmospheric concentrations of climate warming carbon dioxide (CO2), methane and nitrous oxide to levels not seen in at least 800,000 years. Carbon dioxide concentrations have increased by 40 per cent since pre-industrial times, primarily from fossil fuel emissions, as well as land use changes, such as deforestation. The ocean has absorbed about 30 per cent of the CO2, causing ocean acidification, which threatens marine life.

This comes from the Fifth Assessment Report on climate change by the IPCC. It is based on millions of observations and 9,200 scientific publications.

Global temperature increase

Global temperature increase

It says: “Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased. Over the last two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink almost worldwide, and Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent.”

The world’s top climate scientists warned the planet is committed to centuries of a changed climate, even if emissions stop now. Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions.

A changing climate means the world faces a series of risks.

Over the past few decades there have been more heat waves and heavy rainfalls in parts of the world. Thomas Stocker, co-chair of an IPPC Working Group said, “Heat waves are very likely to occur more frequently and last longer. As the Earth warms, we expect to see currently wet regions receiving more rainfall, and dry regions receiving less, although there will be exceptions.”

His remarks came after the worst flooding in Alberta’s history, a flash flood that shut down traffic, including a train, in Toronto, and floods in Colorado that killed a number of people.

Over the last two decades, the Greenland and Antarctic ice sheets have been shrinking at an increasing rate, glaciers have continued to decline almost worldwide, and Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease. As the ocean warms, and glaciers and ice sheets shrink, global sea level will continue to rise, but at a faster rate than over the past 40 years. This will lead to more coastal flooding.

Tara,Arctic,2013

Research ship Tara sails around the Arctic, 2013

As if to add an exclamation point to the IPCC report, a large freighter sailed through the Northwest Passage this fall. The Nordic Orion carried a load of coal (which releases greenhouse gases when burned) from Vancouver, bound for Finland. This summer and fall the Tara, a sailing yacht doing scientific research, circumnavigated the Arctic, finishing by the Northwest Passage. It is operated by a French non-profit environmental organization.

 

 

 

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