CO2: Friend or Foe to Agriculture?

Rep. Lamar Smith said climate change “alarmists” ignore the “positive impacts” of more carbon dioxide in the atmosphere, such as increased food production and quality. But the impact of increased CO₂ levels on agriculture is more complicated than that — and, on balance, likely negative, particularly in the future.

Other factors aside, an atmosphere with more CO₂ does boost crop yield in the short term via increased rates of photosynthesis. In the long term, multiple experts told us the positive effect of increased CO₂ on crops will diminish and the negative impacts of climate change, such as higher temperatures and extreme rainfall, will grow.

Smith, the chairman of the House Committee on Science, Space & Technology, made his claim in a July 24 op-ed published in the Daily Signal, a news website created by the conservative Heritage Foundation.

Smith, July 24:  A higher concentration of carbon dioxide in our atmosphere would aid photosynthesis, which in turn contributes to increased plant growth. This correlates to a greater volume of food production and better quality food. Studies indicate that crops would utilize water more efficiently, requiring less water. And colder areas along the farm belt will experience longer growing seasons.

In making his claim, Smith also argued, “The American people should be made aware of both the negative and positive impacts of carbon dioxide in the atmosphere,” adding, “Without the whole story, how can we expect