Final answer:
Two trillion tons of CO₂ have been emitted into the atmosphere from the burning of fossil fuels. This estimate considers that about half of these emissions stay in the atmosphere, with the remainder being absorbed by other means such as oceans and land.
The correct answer is option b two trillion tons.
Step-by-step explanation:
The student's question about CO₂ emissions from the burning of fossil fuels is best estimated to be about two trillion tons. This assessment comes from combining empirical data and historical usage trends of fossil fuels, alongside our understanding of their chemistry and the observed atmospheric CO₂ concentration increases, as presented in various figures and tables in scientific literature. It is recognized that approximately half of the emitted CO₂ stays in the atmosphere while the rest is absorbed by oceans and land.
The overall rate of CO₂ emissions continues to rise, primarily because of the increased consumption of oil and gas. Current projections imply that CO₂ concentrations could double the pre-industrial levels by 2050, leading to significant climate change implications such as increased global temperatures.