Al Gore’s agitprop documentary opens in theatres next week, and all our liberals friends will soon be running around in circles, crying: “The sky is falling!” Editorials will proclaim that Gore has definitively proven environmental disaster stemming from anthropogenic climate change is well underway, and dangerously accelerating. My college classmates will be buzzing like a hive of bees on the class email list.

Time to read the National Center for Policy Analysis’ debunking study No 285: Climate Science: Climate Change and Its Impacts. Swimming polar bears and color-changing coral reefs are rapidly headed your way.

Scientific debate continues regarding the extent to which human activities contribute to global warming and what the potential impact on the environment might be. Importantly, much of the scientific evidence contradicts assertions that substantial global warming is likely to occur soon and that the predicted warming will harm the Earth’s biosphere.

The Earth’s climate began a warming trend after the “Little Ice Age” ended in the mid-1800s, long before global industrial development led to substantial increases in greenhouse gases beginning in the middle of the 20th century. About half of the warming during the 20th century occurred prior to the 1940s, and natural variability accounts for all or nearly all of the warming.

To assess future climate trends, climatologists rely upon General Circulation Models (GCMs) that attempt to describe Earth’s climate. The many climate models in use vary widely with respect to the variables they include and in the assumptions they make about how those variables interact. Yet some official reports, including the U.S. National Assessment published in 2000, report only the most extreme predictions, ignoring others that project only moderate warming in the 21st century.