Soapbox: ‘Why worry’ about climate change? It’s real
The Coloradoan’s April 2 Soapbox, “Global warming advocates are the ones with heads in sand,” was unfortunately riddled with mischaracterizations and factual errors.
The author implies that readers should not be concerned about climate change because he feels that he can so easily poke holes in the accumulated consensus of the global scientific community, and because “climate changes all the time.” Of course, scientists are very aware of past climate changes and conditions (indeed, going back billions of years) on our planet. What is different today is that, among other things, we are forcing a sensitive climate system with an unprecedented spike in the carbon dioxide concentration in an era where a huge human population is dependent on the recent climate. This is also occurring when many of the nonhuman organisms on the planet are highly marginalized by the human appropriation of vast amounts of habitat. Our carbon dioxide spike, simply put, is trapping more solar heat in the atmosphere and oceans. This heat has to go somewhere, and it affects the atmosphere, oceans and all that depend on them in a myriad of ways.
Just two areas where the Soapbox was way off base in characterizing the climate system were on the effects of volcanic eruptions and solar intensity changes. Large volcanic eruptions can indeed have impressive effects on the atmosphere, but they actually have a limited (and cooling) effect because they temporarily inject aerosols into the upper atmosphere, and these small particles temporarily reduce the level of sunlight reaching the lower atmosphere and surface. However, regarding the carbon dioxide budget, volcanoes are actually minor players. The average carbon dioxide contribution from volcanoes has been estimated (by the U.S. Geological Survey and others) to be around 200 million tons per year. Present emissions arising from human activities are more than 100 times this, or about 37 billion tons.
Another frequent canard expressed in the Soapbox is that the output of the sun has something to do with the recent global heat buildup, and might even cause things to cool soon. This statement seems to imply that the global scientific community inexplicably has forgotten to think about this. Of course, people who spend their careers thinking about such things have in fact given this issue lots of thought, and for many decades. Recent changes in solar insolation, measured by satellites, do not explain the recent increase in the average temperature of the planet. Furthermore, the effect of growing greenhouse gas concentrations would swamp even small decreases that might occur, based on consideration of the historical record.
The off-hand comment about the Pacific Decadal Oscillation is also a red herring; these cycles simply distribute heat around the planet and between the oceans and atmosphere; they do not affect the total amount of heat in the system.
Overall, the Soapbox, most egregiously, in my opinion, promotes a “why worry?” attitude. This position callously ignores the enormous global population at risk (and in some cases already being displaced by changes in precipitation, temperature and sea level).
For readers who truly want to explore the issues of present-day climate change free of mischaracterization and misdirection, I invite them to visit an excellent summary of common questions and answers for the general public (including the ones addressed here) at http://royalsociety.org/policy/projects/climate-evidence-causes/.
Rick Aster is a geophysicist and a Fort Collins resident.