Final answer:
Atmospheric CO₂ concentration is unlikely to stabilize immediately after CO₂ emissions level off due to the long residence time of CO₂ in the atmosphere and ongoing temperature rise as the oceans adjust to higher CO₂ levels.
Step-by-step explanation:
Once CO₂ emissions are leveling off, the atmospheric CO₂ concentration may not immediately stabilize. This is because CO₂ remains in the atmosphere for a long time after it is emitted. The atmospheric concentration of CO₂ has risen from pre-industrial levels of about 280 ppm to over 400 ppm today, with human activities such as burning fossil fuels being a major contributor to this increase. The excess CO₂ in the atmosphere acts as a 'bathtub' filling faster than it can drain, meaning CO₂ accumulates over time, and this accumulated CO₂ continues to affect the Earth's temperature even after emissions are reduced. Furthermore, as the oceans slowly adjust to the new radiative reality imposed by higher atmospheric CO₂ levels, Earth's temperature will continue to rise, indicating that immediate stabilization of CO₂ concentrations is unlikely.