The True about OIL and fossil fuels

We know that oxygen gas present in the atmosphere and allowing us to breath has been produced as a by-product of photosynthesis, which occurs in plants, allowing them to produce organic matter, used as food by animals. Plants use carbon dioxide gas, present in the atmosphere, incorporating its carbon into organic matter, and liberating oxygen gas. Free oxygen gas is present in the atmosphere because some of the organic matter produced over the ages has not been consumed, forming on geological time scales deposits of coal, oil and natural gas, commonly known as fossil fuels. Therefore, knowing the amount of oxygen in the atmosphere, we can deduce the amount of fossil fuels buried underground, expressed as equivalent carbon. To do that, we shall write a simplified chemical equation of photosynthesis that most schoolchildren are able to understand:
hv + CO2 = C + O2

Here, hv represents the solar light energy, CO2 - carbon dioxide gas, C - equivalent organic carbon, which is mostly incorporated into a sugar, glucose, and O2 - oxygen gas. This equation states that one molecule of carbon dioxide gas yields one carbon atom, incorporated into organic matter, and one molecule of oxygen gas, which is equivalent to mass conservation - atoms don't disappear, nor are they created from nothing. Using the Periodic Table, we obtain that for each 12 grams of carbon incorporated into organic matter by plants, 32 grams of oxygen gas are liberated. Using Wikipedia, we can find the data on the total amount of oxygen present in the atmosphere, and calculate that it corresponds to about 2 tons of oxygen per each square meter of the Earth's surface area. Doing a proportion, we get that there exist, buried, some 0.8 tons of carbon, on average, per square meter of the Earth's surface area. Of these, once more using Wikipedia, the known and confirmed deposits of coal, oil and natural gas correspond to less than 3 kilograms per square meter, which makes about 0.3% of the total. These known deposits will sustain world economy for at least a century, therefore, we still have fossil fuels for thousands of years to come, under any thinkable development scenario of the world economy and demographics.Make your own conclusions on whether we need very expensive windmills or extremely expensive photovoltaic installations, recalling that, contrary to what IPCC says, CO2 - the "pollutant" that plants need to feed us - does not affect the climate to any measurable extent.