There is only one molecule of carbon to two molecules of oxygen. The subscript number 2 indicates there are two molecules of oxygen.
Carbon dioxide is a necessary gas for Earth as is every greenhouse gas. Carbon dioxide is extremely stable and does not dissipate for a very long time.
That is a desirable quality for Earth as it supports a temperature on Earth that allows life to exist. The problem enters when there is an over abundance of CO2 and the heat trapping quality of CO2 grows with added CO2 to an atmosphere already warm and in support of the life on Earth.
Kindly consider Earth was doing very well all by itself in supporting life on a comfortably warm planet. It didn't need any help. Earth for millions of years supplied it's own warmth in greenhouse gases that allowed evolution of plants and animals. Earth was an incubator to life just the way it existed. Perfect.
It was the use of coal, coke, oil and natural gas beginning in the late 1800s during the Industrial Revolution that shifted the natural balance of Earth.
There are all kinds of weird things said about the natural world and carbon dioxide emissions and how there is more CO2 in the natural world than in any burning of fossil fuels. That is true by the way. Carbon dioxide emissions in the natural world are higher than burning fossil fuels, but, remember before the greenhouse gas imbalance began plants and animals, including people, supplied the need for global warming. One plant and one animal could not impose a warming layer of greenhouse gases. It took a population of flora and fauna to enjoy the balance of Earth's warmth.
Greenhouse gases do break down over time, so if there were little symbiosis between life on Earth with the necessary gases to keep the planet warm, there would be no life on Earth. When one finally takes the time to realize what is happening with Earth as a planet full of life it gets to be very interesting. Very interesting.
No one finds the idea that animals exhale carbon dioxide and plants primarily exhale oxygen an interesting thought?
Does the knowledge to the breakdown of greenhouse gases in the atmospheres worry anyone? No?