CO2 a pollutant?

If CO2 is bad why do I want to buy products like this for my aquarium? Answer: To encourage plant growth and vitality.

This is also why greenhouse growers routinely inject the exhaust gases from their fossil-fuel or wood-fired heaters into the greenhouse to enhance growth.

Actually, CO2 depletion is what will kill life as we know it on this planet. Over the ages the amount of CO2 has been declining. Not only coal and oil and shale but also limestone and marble are all made from CO2 taken out of the air.

Practically all plants today first appeared when CO2 levels were about 5 times today’s levels. As CO2 drops due to things such as the erosion of the Himalayas, plants become less and less healthy. At some points the species that are less efficient at using CO2 become less healthy and their populations begin to dwindle. Species that are more efficient, take over which is why deciduous trees have replaced conifers in a good part of the world. Deciduous trees drop their leaves on the ground in winter and these decay creating additional CO2 for the trees during the next growing season.

As CO2 levels drop further, plants begin to die off and over a period, more and more would go extinct. As the plants die off, the animals that depend on them (that would include people) also begin to die off and eventually you have a long, slow, mass extinction event.

CO2 is not harmful at today’s levels in the environment. In fact, it will invigorate plant life and make for a healthier environment for the animals that depend on those plants.

It is not surprising that plants prefer higher CO2 levels than the present levels. CO2 has been much higher for most of the history of life than it is today. See the following graph ( based on carbon dating from rock, ice samples etc. detailed in http://www.geocraft.com/WVFossils/Reference_Docs/Geocarb_III-Berner.pdf ) of global temperature and CO2 levels for the past 600 million years. Note that during the Cambrian, when large life-forms first evolved, CO2 was at 7,000 ppm, nearly 20 times present levels. Note, To the consternation of global warming proponents, the Late Ordovician Period was also an Ice Age while at the same time CO2 concentrations then were nearly 12 times higher than today-- 4400 ppm