The rate of deforestation where growing population have asked for more space either for settlement or agriculture has reduced the level of oxygen in the atmosphere and accelerated the emission of Carbon dioxide. A lot of bush fires have also contributed to the CO2 emissions. While I write on this, I cannot ignore the fact that when earth surface is dug, a lot of carbon stored in the earth's crust is released in the atmosphere (common in mining perhaps).

Kenneth M Towe

Yes the level of carbon dioxide has conclusively increased starting with agricultural revolution about 8,000 years ago and accelerating with industrial revolution and increasing drastically since the world wars. This increase from 180 to over 400 ppm is due to anthropomorphic causes human activity. The red herring of saying this is relative to oxygen is interesting. Oxygen has been pretty stable at about 21% for the last 600 million years. There is no credible information that would suggest carbon dioxide has not risen and indeed all information shows it is continuning to increase.

Yes, Co2 is increasing but for agriculture co2 is the main fertilizer. Now its the ability of plant to use Co2 upto its maximum capacity.

Co2 is raw material for plant industry.

The net gain of atmospheric Carbon dioxide is a function of respiration exceeding Photosynthetic capacity. The biggest source of respiration is combustion of fossil fuels the ability to increase photosynthesis while decreasing respiration which would start with reducing of fossil fuel use. In terms of energy system changing from Coal to Natural Gas would reduce the energy emission from electricity by over 50%. Other energy sources such as nuclear solar wind and hydroelectric may also contribute to the resolution of the issues. Generating large biomass through photosynthesis is not a solution unless the respiration is reduced. Large quantities of soil Carbon has been contributing to greenhouse gas elevation and the ability to stabilize carbon in recalcitrant forms gives the ability to both improve soils for agriculture and counteract greenhouse enrichment. Biochar and compost can be very effective in those effort. While Ken suggest its all about population the generation of respiration would be resolved with alternative forms of energy and the sequestration is a proven technology that can improve our agriculture and environment. None of these strategies have been fully applied but the conversion of coal to natural gas improves the greenhouse gas equation and the environment without driving costs higher. The use of a new generation of nuclear energy based on thorium is one of resolutions which could be a game changer. Prototypes of thorium reactors were scuttled in the 1960's because they would not support radioactive materials which could be used for nuclear weapons. Technology will be a part of the solution of these issues and the Neo Malthusian ideas which predicted mass disease and global starvation will continue to march on to their tune however erroneous.

@all thank you for your comments and clarifications