Carbon dioxide, or CO₂ for short, is a colorless, odorless gas that plays a key role in Earth's atmosphere. It is a natural component of the air and is central to the planet's carbon cycle. The CO₂ concentration in the atmosphere is about 0.04 percent.
Structural formula of a CO2 molecule (© CiK Solutions GmbH)
In recent decades, however, carbon dioxide has increasingly drawn attention as a greenhouse gas that contributes significantly to climate change. Carbon dioxide is produced both by natural processes and by human activities. Natural sources include volcanic eruptions, decomposition processes, and the respiration of living organisms.
Humans release CO₂ primarily through the burning of fossil fuels, deforestation, and industrial processes. Since the beginning of industrialization, the CO₂ concentration in the atmosphere has risen sharply, which has far-reaching consequences for the global climate. Reducing CO₂ emissions is a key goal in the fight against climate change.
The effects of carbon dioxide are diverse and complex. As a greenhouse gas, it absorbs thermal radiation and thus contributes to global warming. This leads to rising average temperatures, more frequent extreme weather events, and rising sea levels. In addition, more carbon dioxide dissolves in the oceans, leading to ocean acidification and threatening marine ecosystems.
Carbon Dioxide and Hydrogen
In the context of the energy transition, hydrogen plays an important role as a potential low-carbon or even carbon-free alternative. When hydrogen is burned, it produces no carbon dioxide—only water vapor. Green hydrogen, which produces no CO₂ emissions, is particularly promising. However, blue hydrogencan also help reduce greenhouse gas emissions.
Hydrogen technologies could play a key role, particularly in sectors that are difficult to decarbonize, such as the steel industry and heavy-duty transportation. They offer the potential to reduce CO₂ emissions in areas where other solutions reach their limits. The development and expansion of these technologies are therefore a crucial component of society’s overall effort to reduce CO₂ emissions and mitigate climate change.
