I am a retired plant scientist. Over the years I have commented on the essential role that CO2 plays in photosynthesis, the basis of virtually all life on Earth.

In the last two years I have researched the role that CO2 plays in so-called global warming. This is what I have found: Planet Earth is not a greenhouse, an inaccurate analogy.

There is no real evidence that global warming is due to atmospheric CO2. Controlled experiments indicate that the addition of CO2 in air up to 10,000 ppm have little or no effect on warming under atmospheric conditions.

Note the original experiments conducted 150-200 years ago were conducted in a vacuum. We do not live in a vacuum. Credible studies conducted at the turn of the present century indicate that 50% of the warming that we are seeing is due to the direct effects of terrestrial surface heating, due to human activity, (urban heat islands, deforestation and overgrazing). This is especially true in the tropical regions, the main heat reservoir for Earth.

The entire gaseous atmospheric blanket controls the temperature of Earth not just CO2 and H2O vapor, mostly by convection. H2O vapor is the main weather forming component. This is all driven by radiation from the sun. This can be seen from weather satellite videos.

This CO2 model of global warming is an oversimplification at least, and totally wrong at most. We need to get this right before we embark on drastic action like large scale CO2 sequestration.

Greg Fox lives in West Fargo.