Explain how understandin the CO2 cycle helps atmospheric scientists understand/prepare forGlobalClimateChange?

CO2 is a greenhouse gases and one of the main gases in the atmosphere that is responsible for global warming, and water vapor and methane being the next most dangerous. co2 traps the heat inside the atmosphere, not allowing the heat to escape to outer space, hereby increasing the mean surface temp of our planet.... measuring the total CO2 in the atmosphere and how much plants is absorbing and how much are we releasing will help us make models of temperature rise... plants take co2 and remember the more the concentration in the atmosphere, the more faster they tend to grow too.... and co2 is released from volcanic eruptions too... so on overall we calculate the co2 in the atmosphere and we plot the Keeling Curve... at present we measure the co2 at the mauna loa observatory in Hawaii... so we now know how much is it increasing per yr and we can predict it for say next 75 years and we prepare models based on that amount of temperature rise.. and we say rest of the details like due to temperature rise of this much, there would be a major ice melting and the sea level would increase to this much cm at the end of this century...