The Keeling Curve, and What Does It Mean?

In 1958, Dr. Charles (David) Keeling began taking daily measurements of atmospheric carbon dioxide (CO2) atop Mauna Loa in Hawaii.  With his first measurement, taken in March 1958, he recorded an atmospheric CO2 concentration of 313 parts per million (ppm).[1]  Dr. Keeling observed that the CO2 concentration followed a seasonal pattern.  He postulated that atmospheric CO2 decreased during the northern hemisphere summer due to plant growth and increased each winter.  Furthermore, he noted that the average CO2 concentration in the atmosphere increased each year.  He ascribed this to fossil fuel combustion and land use patterns.

Here’s a chart of the Mauna Loa measurements of atmospheric CO2:[2]

In February 2014, the atmospheric CO2 concentration at Mauna Loa has risen to 398 ppm, an increase of 27 percent over 56 years.  Is this significant?  Consider that CO2 levels were around 200 ppm during recent ice ages, and around 280 ppm during warmer interglacial periods.[3]  In my mind, this is incontestable evidence that the recent increase in atmospheric CO2  is caused by human activity.

A number of scientific organizations of national and international standing concur, including the American Meteorological Society, the American Chemical Society, the National Aeronautics and Space Administration, and the National Oceanic and Atmospheric Administration.  Please see the Wikipedia article, Scientific Opinion on Climate Change for a more comprehensive list.[4]

Why do we care about atmospheric CO2?  After all, CO2  is essential for plant life.  More of it may well be a good thing, right?

Consider the following data, taken from Antarctic ice core samples:[5]

Relationship between atmospheric CO2 and Antarctic Temperature for the past 400,000 years or so...

Relationship between atmospheric CO2 and Antarctic Temperature for the past 400,000 years or so…

What does this data tell us?  I look at this graph and I see a correlation between atmospheric CO2 and temperature.  Higher CO2 implies a higher temperature, at least at the poles.  This concurs with the significant reduction in Arctic sea ice over the past dozen years or so.

Why do we care if it gets warmer?  It’s been a pretty cold winter in the northeast United States this year.

Wait a minute…  could the persistent drought in the southwestern U.S. be part of a pattern of climate change?  Could the lack of snow in the Sierra Nevada mountain range be a cause for concern for agriculture in California’s Central Valley?  Could this be somehow related to the fact that the ten warmest years on record have all occurred since 1998?[6]

Average annual temperature since the start of the Industrial Revolution

Average Annual Temperature

I’m not a scientist.  But the data is pretty convincing to me.  The world is getting warmer, quickly, with unpleasant consequences in the wings.  And we humans largely to blame for it.

Admittedly, climate science is inexact, has many variables, and we have a lot yet to learn about it.  So does western medicine.  Yet, we don’t insist that journalists give equal time to the witch doctors of Papau New Guinea to dispute the rationale of western medical techniques.  So why do Fox News and the Republican Party give a voice to those who would debate what is obvious to 97% of those who specialize in climate science?  Is it for the money?  Or do they just prefer to take a free market approach, and let Nature take its course, whatever the outcome?

Perhaps the answer lies in who’s behind some of the doubting scientists.  Some of them used to doubt the existence of a causative link between tobacco use and lung cancer when their funding came from the Tobacco Institute.  Today, they get their funding from somewhere else…  the Koch brothers, perhaps?

Next time I go to the beach, I’m renting.

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