Posts Tagged ‘Salmon’


Salmon and Sea-Level

August 8, 2009

I recently wrote about  the alarmist claim that sea level rise in British Columbia is going to have a serious negative impact on their Salmon population.  An environmental activist playing at journalist wrote for the Victoria Times Colonist:

“The spectre of rising sea levels and ecological change from climate disruption show land-use plans for Vancouver Island and the B.C. coast will need to be revisited and recalibrated to account for rapid and unabated climate change.”

“‘Once set in motion, sea-level rise is impossible to stop. The only chance we have to limit sea-level rise to manageable levels is to reduce emissions very quickly, early in this century. Later it will be too late to do much,’ says senior NASA scientist Stefan Rahmstorf in a recent article for the United Nations Office for the Co-ordination of Humanitarian Affairs.”

There may be a lot of man made obstacles to Salmon survival, such as dams, over-fishing, etc., but sea-level rise is not one of them. 

Let’s get right down to the nitty-gritty.

Salmon have been around for about 500,000 to 1,000,000 years, give or take a few hundred thousand.  This is not a praticularly long time, nevertheless, Pacific Salmon diversified into multiple species, including Cherry Salmon, Sockeye Salmon, Chinook Salmon, Pink Salmon, Chum Salmon, and Coho Salmon.  There are also Atlantic Salmon and even land-locked Salmon.

Will the sea level  rise of the 21st century end the salmon’s success?  Not likely.  Take a look at these sea-level rise rates from Alaska, one of the Salmon’s primary habitats:

Yes, that right, the sea level is dropping at almost all locations where it is measured in Alaska.  So, it doesn’t look like sea level rise is likely to be much of a threat to the salmon in Alaska or British Columbia

But let’s pretend for a moment that the seas will rise dramatically over the next century, or longer.  Would the Salmon survive this dire situation?   If the past is any indication, the Salmon should pull through.  Take a good look at the graph of Holocene sea-level in the graph below. 

Image created by Robert A. Rohde / Global Warming Art.  Go to

Image created by Robert A. Rohde / Global Warming Art. Go to

Notice that from about 12,000 14,000 years ago until about 8,000 years ago the sea rose about 120 100 meters.  So, the sea level rose about 2 meters per century for 40 60 straight centuries in the recent (geologically speaking) past!  But the Salmon somehow survived.

What effect did this sea-level rise have on the Salmon’s habitat?  The movie below shows Beringia, consisting of the eastern part of Siberia and Alaska from 21,000 years ago to the present.  Look what happens from 12,000 years ago to 8,000 years ago.  I would judge that as a pretty dramatic change of the Salmon habitat.  Yet they seem to have thrived.  I think they will survive sea-level rise this century.

Barengia 21,000 years ago to present. (NOAA)

Barengia 21,000 years ago to present. (NOAA)