I sent this Wall Street Journal online link to Dr. Bruce Matthews, the Interim Dean of UH Hilo's College of Ag and Forestry.
Rising carbon-dioxide levels are slightly helping crops compete against weeds.
Two rival designs of plant biochemistry compete to dominate the globe. One, called C3 after the number of carbon atoms in the initial sugars it makes, is old, but still dominant. Rice is a C3 plant. The other, called C4, is newer in evolutionary history, and now has about 21% of the photosynthesis "market." Corn is a C4 plant. In hot weather, the C3 mechanism becomes inefficient at grabbing carbon dioxide from the air, but in cool weather C4 stops working altogether. So at first glance it seems as if global warming should benefit C4.... Read the rest