Final answer:
Global carbon sources and sinks are currently not balanced, and human activities are causing an increase in atmospheric CO₂ levels.
Step-by-step explanation:
The global carbon cycle involves the movement of carbon between different reservoirs on Earth, such as the atmosphere, biosphere, upper oceans, and deep oceans. Currently, global carbon sources and sinks are not balanced. Natural emissions of CO₂ from these reservoirs are in balance with absorption, but human activities, including the burning of fossil fuels and deforestation, are releasing more carbon into the atmosphere than can be absorbed. As a result, atmospheric CO₂ levels have been steadily increasing, leading to climate change and its consequences.