Thursday, March 22, 2012

A little science can be dangerous....

Rick Santorum not only doesn't accept evolution but he is a well known global warming sceptic. Recently he has attempted to give a science lesson on photosynthesis, noting quite correctly that plants require carbon dioxide-carbon dioxide being a raw material for photosynthesis. Therefore carbon dioxide can't be bad. So he has bought into the same sort of reasoning promulgated by the site CO2 Science which collects data on how much better plants grow when carbon dioxide levels increase. This video, Seeing is Believing, is pretty representative of what's on CO2 Science and is pretty effective and quite correct as far as it goes. Under controlled conditions and with plenty of other nutrients carbon dioxide does make plants grow better. But there are some big questions as to whether or not this increased plant growth will be sufficient to overcome the increase of carbon dioxide due to human activity. Some studies such as this one suggest that soils in forests can take up extra carbon in response to increased carbon dioxide levels. Sounds fine- but as noted by this primer on carbon dioxide and the carbon cycle, human activity such as deforestation has caused a net release of carbon dioxide to the atmosphere. Plus, as oceans warm they also become less able to absorb carbon dioxide. One can argue about what will happen long term-but if the plants and other photosynthetic organisms are able to take up sufficient carbon dioxide why are atmospheric carbon dioxide levels still increasing with no sign of slowing? See this diagram from NOAA. Somehow the global warming skeptics who argue that plants can soak up the carbon dioxide are missing the big point- they may be right in theory , but globally something is awry with this thinking. Either on a global scale, plants and other photosynthetic organisms are not responding as "common sense" says they should or human activity is reducing the ability of natural systems to respond, as they other wise might, to increasing carbon dioxide concentrations.
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