Paul Linsenís recent letter to DLN on climate change follows several others posted by conservative writers who dismiss this phenomena as a natural event and unaffected by manís activities. Unfortunately he and his colleagues, for the most part, fail to cite critical aspects of the nuanced science behind climate change.
The facts are these. Carbon dioxide levels in the atmosphere have reached the highest levels ever recorded (400 parts per million or ppm). They have increased 100 ppm in just 120 years. A natural change of 100 ppm normally takes 5,000 to 20,000 years. Although our output of 29 gigatons of CO2 is tiny compared to the 750 gigatons moving through the carbon cycle each year, it adds up because the land and ocean cannot absorb all of the extra CO2. About 40 percent of this additional CO2 is absorbed. The rest remains in the atmosphere, and as a consequence, atmospheric CO2 is at its highest level in 15 million to 20 million years, according to a study by Tripati (2009).
Also, according to NOAA, average global temperatures have increased roughly 1 degree since 1880. Although there have been periods of constancy (1940-1970) since 1970 these temperatures have steadily risen. Despite what they advocate the IPCC models (see Climate Progress website) that have been developed to predict temperature trends have been remarkably reliable as compared to real data and have refuted the predictions of contrarian researchers of which there are a vocal handful.
Satellite-based measurements reported by NOAA also show sea level is rising at a rate of 0.12 inches per year. This is not due to land mass subsidence as suggested by Linsen but, simply, by more liquid water in the oceans. The source of this water is from melting ice primarily held above sea level elevation in the most northern and southern regions of the world. It is well documented that mountain and coastal glaciers have shrunk in size over several decades. The polar ice cap has done the same and this year has reached the lowest levels ever recorded. Although ice held in Antarctica is more or less stable, the net liquid water input into the oceans from melting ice has obviously resulted in a progressive sea level rise.
Lastly, consider what happens when more CO2 is released from outside of the natural carbon cycle by burning fossil fuels. Human CO2 emissions upset the natural balance of the carbon cycle. Man-made CO2 in the atmosphere has increased by a third since the pre-industrial era, creating an artificial forcing of global temperatures which appears to be warming the planet. While fossil-fuel derived CO2 is a very small component of the global carbon cycle, the extra CO2 is cumulative because the natural carbon exchange cannot absorb all the additional CO2. The level of atmospheric CO2 is building up, the additional CO2 is being produced by burning fossil fuels, and that build up is accelerating.
Although I would disagree that carbon-based controls on industry could ďwreckĒ the economy, the direction of CO2 emissions in the U.S. seems to be downward according to recent EPA data. In large part, this is due to greater efficiencies in industrial energy use (resulting in a major cost savings), the use of lower cost and more abundant natural gas (replacing more costly oil and coal), more efficient automobiles, and a flattening out of consumer energy use. Renewable energy sources such as wind turbines and solar panels have their place and own set of impacts but are not the ultimate solution to the climate change problem as they cannot alone meet demand on a real-time basis. However, the increased use of natural gas coupled with renewables and other energy conserving efforts could have a major downward and/or stabilizing impact on U.S. carbon dioxide emissions.