Times when the man made CO2 cycle was closed within a few years

The earth during the last million years traditionally had a CO2 concentration in the atmosphere of around 200 to 300 ppm – parts per million. Humans have used energy for many thousands of years for their comfort, for protection and to prepare food. The fire was a constant companion of humans and they were burning renewable sources of energy, mostly wood. Trees and other plants absorb solar energy by photosynthesis and store this energy carbon-based in wood and other organic material. Whenever man has burned such carrier of stored energy, let’s say the wood of a tree, CO2 was released into the atmosphere. However, the CO2 cycle was closed in the sense that the same amount of CO2, molecule by molecule, was extracted from the atmosphere shortly before, only a few years ago during photosynthesis when the tree was growing.

When you burn the wood of a tree you release CO2 into the environment that has been taken out of it only some years earlier. The tree then absorbed water H2O and carbon dioxide CO2 from its environment plus sunlight energy to form its wood. The cycle to absorb CO2 from and to release it back into the atmosphere closes within a few years.

Therefore there was a balance of extraction and release of CO2 from and into our environment.

The disturbed CO2 cycle

Since the industrial revolution mankind has an ever-increasing demand for stored energy. Sources of energy, which naturally grow in our forests and fields, became less and less sufficient to satisfy the demand for energy. For more than a century, man removes fossil sources of stored energy from inside the earth crust in form of coal, oil or natural gas and burns it. Here, the CO2 cycle is not closed within a sort time frame. The plants, which are the basis of fossil energy, were growing and did their photosynthesis many millions of years ago. They have extracted CO2 from the environment over many millions of years. And now we release it back into the environment in a comparatively very short time frame. Extraction of CO2 from the atmosphere and release back into it is in imbalance. By burning fossil fuels we release much more CO2 into our environment than growing plants extract from it and store it as carbon compounds.

As a consequence the CO2 concentration in our atmosphere is increasing. It has reached a level of about 400 ppm, so almost double the concentration our earth had in historic ages, and it is ever increasing.


The CO2 concentration in the northern hemisphere is slightly higher than in the southern hemisphere. This is where most fossil fuels are burnt. It indicates that the CO2 concentration is man-made.


The CO2 cycle only closes after many million years. This means we are on the way to bring into being an atmosphere and ocean environment, which we had many million years ago.

More atmospheric CO2 leads to global warming and climate change

So why is the amount of CO2 in our atmosphere important? The problem is that CO2 is a greenhouse gas. It captures heat radiated from the earth’ surface. Therefore the temperature on our earth and the CO2 concentration in the atmosphere are closely linked together. This leads to global warming and climate change.


The greenhouse effect

Greenhouse gases reflect infrared radiation (= heat) from the earth’s surface. The atmosphere warms up.

The average temperature on earth

The global warming effect resembles the global increase in CO2 concentration in our atmosphere.


Graphic: NASA


The effects of global warming and climate change

The effects of global warming and climate change are manifold. Climate zones change and precipitation (rainfall and snowfall) patterns alter with adverse effects on animals, plants and agriculture. Weather related natural disasters increase in force and frequency, and sea levels rise, to name a few. This can lead to shortness of drinking water, droughts and large-scale human migration. There might be a self-excitation of further warming factors, such as additional release of greenhouse gases from melting permafrost areas. Some scientists even predict that climate change can result – and has been resulted in the past – in a catastrophic elimination of almost all species.

Mankind has to decrease utilization of fossil fuels

Next to global warming, fossil resources of energy are limited and one can expect increased costs to harvest these, resulting in increased prices for energy.

Nuclear energy bears the risk of huge disasters. The long-term disposal of nuclear waste carries further risk.

Therefore, mankind has to decrease its dependency on fossil fuels to avoid these negative effects and to preserve our creation. Regenerative sources of energy need to be used to satisfy our demand for energy.


Graphic: NASA


Picture: The effects of global warming: Melting ice on the oceans. Source: NASA