The observational evidence that the Earth is warming is overwhelming and unmistakable.
Surface observations of temperature over land and ocean have shown that all but one of the 15 warmest years on record have occurred since 2000. the average length of the ice season on a collection of widely distributed Northern Hemisphere lakes, each with at least 150 years of continuous record, has decreased by over two weeks. The areal extent of the Northern Hemisphere’s wintertime cold pool has systematically shrunk in the last two winters recording the smallest seasonal average cold pool areas since records began in 1948-1949.
Lurking behind the curtain on all of these observations of warming and its effects is the additional observation that the carbon dioxide fraction in the atmosphere – which has a well understood physical relationship to global physical temperature – has grown to levels not seen in at least the last 800,000 years. This increase is demonstrably related to the combustion of carbon-based fossil fuels, a global business enterprise in which careful accounting of the extraction, sale and use of this valuable commodity leaves no ambiguity about the amount of CO2 that has been added to the atmosphere through its usage.
In spite of this clear evidence, only one of the Republicans seeking the nomination for president, Sen. Lindsey Graham, unequivocally accepts the scientific consensus on this issue.
Sen. Ted Cruz accuses scientists of “cooking the books” while asserting no warming has occurred over the past two decades. Our own Gov. Walker agrees, as stated clearly by his spokesperson on Aug. 3: “Gove. Walker believes facts have shown that there has not been any measurable warming in the last 15 or 20 years.” This is patently false.
A healthy debate regarding what actions to take in response to the reality of global warming is entirely appropriate. Continuing to argue over whether or not a problem exists is irresponsible.