Saturday, January 31, 2015

Cherry Pickers Deny Global Warming

Global warming deniers are like a broken record, repeating the same old climate change myths.  It is always possible to find supposed counterexamples to any well-established and impeccably-tested scientific theory such as evolution, the big bang theory, the germ theory of disease, etc. by cherry picking the data.  This despicable practice is forbidden by the scientific community, and those who practice it are censured and shunned.  Unfortunately, cherry picking is the favorite tool of politicians, lobbyists, and purveyors of ideology, who use it unashamedly with impunity.

Take the claim that global warming has stalled.  A plot of the mean global land-ocean temperature shows that the 2013 temperature is indeed below the 1998 value.  However, such variations are well within the expected range of statistical fluctuations.  Taken out of context and ignoring the rest of the dataset leads to the erroneous conclusion that warming has stopped.  The long-term trend is clear and agreement between the data and computer models (within computational and measurement uncertainties, of course) increases our confidence in the results.

What about the claim that scientists are changing terminology in an effort to hide the perception that global warming has stopped?  To be precise, the earth is experiencing global heating.  It is a fact that CO2 is a greenhouse gas that traps heat, which warms the atmosphere, land and oceans.  Manifestations of heating include temperature increase, evaporation of water, melting of ice, volatility, and changes in climate patterns.  Deniers see a conspiracy in what they believe is an intentional obfuscation on the part of scientists.  The fact that the media uses different words or has changed its terminology is irrelevant to the underlying facts.  The terms  global warming and climate change have been used by scientists for decades, and it has always been understood that these are consequences of heating.

Deniers like to downplay the scientific consensus.  According to several studies that analyze the vast literature on climate change, more than 97% of active climate scientists conclude that the data supports anthropogenic climate change.  The most meticulous study of this sort assembled a list of researchers who are both active climate scientists (judged by numbers of publications in refereed journals), and who have been signatories of public statements that either support or denounce anthropogenic climate change.  This study confirms the 97% figure.  Global warming deniers point to one specific report that suffers from a documented flaw in its methodology as evidence that the 97% number is incorrect.  They ignore all the other studies that confirm the sentiments of 97% of the climate researchers who concur that global warming is real.

Deniers call for productive discussions on climate change.  These are already taking place. Vigorous debate is common at scientific conferences, new and updated studies are inundating the journals with data, and interpretations of the data are continually being fine-tuned.  Scientists are not zombies who tow the party line.  Only after years of debate is a scientific consensus reached; and even then, scientists doggedly try to find holes in the evidence.  In contrast, the climate change denying machine cherry picks the data in a deliberate effort to cast doubt and plant misinformation in the popular press.

Demanding 100% certainty before taking action on global warming is a stalling tactic.  Prudence demands that steps be taken in proportion to the degree of confidence in the information.  Public debate should focus on finding the most economical ways with the greatest impact on reducing greenhouse gas emissions.  The scientists who have the deepest and broadest understanding of the literature have reached a consensus based on the preponderance of evidence.  We are fools for not heeding their warnings.

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