Carbon Dioxide consists of two oxygen atoms covalently joined to a central carbon atom. The three atoms lie in a line (it is a linear molecule). The central carbon atom (black) is pictured as a sphere drawn at the scale of the carbon covalent radius just touching two oxygen atoms (red) drawn at the scale of their covalent radii. The transparent spheres represent the van der Waals surfaces of the carbon and oxygen atoms.
Carbon Dioxide Emissions are considered a major threat to the Earth because of their capacity modify the climate by insulating the surface and so creating a GREENHOUSE EFFECT.