Seattle Times Climate Lab Misinforms about Climate Change, Sea-Level Rise, and Seattle Flooding – Watts Up With That?

From the Cliff Mass Weather Blog

Yes, we are talking about another Seattle Times ClimateLab article.  ClimateLab is sponsored journalism, whereby advocacy groups pay for “journalism”, which coincidentally supports the group’s positions.   

The story is about flooding in the South Park neighborhood of Seattle, a community built on the floodplain of the Duwamish River.   An area that has flooded regularly for millennia.  

The Seattle Times makes the unfounded claim that human-caused global warming is a major driver of the flooding….suggesting that the major flood of December 17, 2022, demonstrates that this neighborhood is “on the front lines of climate change“.   

The article states that South Park has to “brace for climate change” and by mid-century (2050) that the water level should rise by another foot.

As I will prove below, the Seattle Times claims are clearly contradicted by clear scientific evidence.  

Go back to the 1890s, and the South Park area was a mud flat the frequently flooded (see map from 1894 below.

As one would expect of the flood plain of the Duwammish, this area has flooded many times during the past 130 years– hardly requiring global warming, which only became significant in the 1970s and 1980s.

The recent Times article highlighted the major South Park flood of December 27, 2022.  This event brought flooding to the South Park area as water levels rose to 15 feet MLLW, the mean lower low water level, which represents the average of the lowest low water for each day, calculated over a 19-year period. 

The water was very high because of several factors occurring simultaneously:  a very large astronomical King Tide associated with the moon and sun being aligned during a favorable time of the year, very low and unusual atmospherc pressure (which caused water levels to rise), and heavy prior rain, that revved up the Dumaamish River.

None of these were associated with global warming.

The Seattle Times seems to think that the key element of the local sea level rise is a warming world. 

Don’t get me wrong. Global warming HAS caused water levels to rise very slowly, but so slowly that its effects are essentially in the noise level for big events like the flood in question..  

Let me prove this to you.  Below is the sea level trend at Seattle starting in 1900.  Note that sea level has been going up for a long time— including earlier periods (before 1970) when human-caused warming would be very small.

On average, Seattle’s sea level has risen about 2.09 mm (.08 inches) per year.  So over the past fifty years, a period where rising CO2 levels and associated warming became significant, the sea level in Seattle rose about 4 inches.

So perhaps 4 inches of the 15 feet of the extreme water level during that 2022 flood MIGHT be explained by human-caused global warming.

That is TWO PERCENT.  I repeat 2%.   So why in the world is the Seattle Times ClimateLab pointing its finger at global warming?   Such claims are contrary to data.

I think you know why.

But it is worse than that.  Considering the sea level was rising before human CO2 emissions were significant, how do we know that some of the recent rise was not natural?  In fact, that seems more likely than not.

And to add to the climate change hype, the Seattle Times suggests that Seattle’s sea level will rise another foot by 2050….25 years from now.  This is silly.

 Since there appears to be no acceleration of the sea level rise in Seattle during he past decades, let’s extrapolate the historical rate for 25 years.  You get 2 inches.  Still very small.

Go crazy, double that amount.  Still very small compared to astronomical and meteorological factors that are independent of global warming.