The increase in greenhouse gases has risen by 30 percent over the past 64 years. It is manmade, a fact scientifically proven by the observation that the small proportion of carbon isotope C-12 has significantly decreased compared to the large proportion of C-14 atoms in the atmosphere since the beginning of industrialization. This is because burning fossil fuels only produces C-14 atoms but no C-12 isotopes. In paleoclimatology, Earth's climate history is analyzed based on geological evidence, proxy data, and model simulations. A graph illustrates the temperature trend and CO₂ concentration over the past 100 million years and presents three scenarios for the next 200 years.