By 1904, Arrhenius became concerned with rapid increases in anthropogenic carbon emissions and recognized that “the slight percentage of carbonic acid in the atmosphere may, by the advances of industry, be changed to a noticeable degree in the course of a few centuries.” He eventually made the suggestion that an increase in atmospheric carbon dioxide due to the burning of fossil fuels could be beneficial, making the Earth’s climates “more equable,” stimulating plant growth, and providing more food for a larger population. This view differs radically from current concerns over the harmful effects of a global warming caused by industrial emissions and deforestation. Until about 1960, most scientists dismissed the notion as implausible that humans could significantly affect average global temperatures. Today, however, we know that carbon dioxide levels have risen about 25 percent—a rate much faster than Arrhenius first predicted—and average global temperatures have risen about 0.5 degrees Celsius.

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WUWT article

As is often the case at WUWT?, the comments are as interesting as the article itself, what with heavy hitters on both sides of the AGW debate contributing.

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