3. Summary and conclusions

Due to the use of carbonaceous fossil resources in our economic system, the sources of CO ₂ are diverse: transportation, energy production, industrial manufacturing, etc.

The pathways for CO ₂ valorization are also diverse. From carbon dioxide, it is possible to achieve energy production (methanation, algal biofuels, methanol synthesis, etc.) and chemical intermediates (organic synthesis reactions: urea or polymer production, etc.).

Orders of magnitude in terms of “tCO ₂ ” produced from anthropogenic sources (transportation, manufacturing, waste treatment, and energy) or valorizable as “raw material” (chemistry, energy, etc.) are provided in figure