[Illustrations, footnotes and references available in PDF version]
The climate of Alaska has changed considerably over the past 50-plus years. However, human emissions of greenhouse gases are not the primary reason.
Instead, the timing of the swings of a periodic, natural cycle-the Pacific Decadal Oscillation (PDO)-has made a strong imprint on the observed climate of Alaska since the mid-20th century. Despite its established existence and influence, this natural cycle is often overlooked or ignored in zealous attempts to paint the current climate of Alaska as being one primarily molded by the emissions from anthropogenic industrial activities. In truth, the climate of Alaska and the ecosystems influenced by it have been subject to the cycles of the PDO and other natural variations since the end of the last ice age (some 12,000 years ago) and likely for eons prior. It is primarily these natural cycles that are currently shaping Alaska's long-term climate and weather fluctuations.
Local and regional processes are the most important determinants of the climate experienced by local and regional ecosystems, including human populations. Global-scale influences are much harder to detect and their influence on regional-scale changes is uncertain. In fact, global climate models which project changes in future climate are unable to reliably model local and regional changes-the most important ones in our daily lives.
Therefore, efforts to control global processes through local changes are largely useless when it comes to the climate. For instance, the greenhouse gases emitted by human activities each year in the state of Alaska amounts to less than 0.2 percent of the global total human greenhouse gas emissions. Industrial growth in China adds an additional Alaska's worth of carbon dioxide into the atmosphere each and every month (over and above its baseline emissions). This leads to the inescapable conclusion that even a complete cessation of all carbon dioxide emissions originating from Alaska would be subsumed by global greenhouse gas emissions increases in less than three week's time. What's more, carbon dioxide emissions reductions in Alaska would produce no detectable or scientifically meaningful impact on local, regional, or global climate. Unfortunately, the same cannot be said for the economic consequences of greenhouse gas emissions' legislation-they have been recently estimated to be large, and negative, for the citizens of Alaska.