Which provides evidence that humans are causing an increase in the carbon dioxide concentration in the atmosphere?
The net flux of carbon into the atmosphere without including the contribution from burning fossil fuels is negative.
The net flux of carbon out of the atmosphere without including the contribution from burning fossil fuels is zero.
The net flux of carbon out of the atmosphere without including the contribution from burning fossil fuels is negative.
The net flux of carbon into the atmosphere without including the contribution from burning fossil fuels is positive.
A. The net flux of carbon into the atmosphere without including the contribution from burning fossil fuels is negative
To determine which option provides evidence that humans are causing an increase in the carbon dioxide concentration in the atmosphere, we need to understand the concept of net flux and its relationship to carbon dioxide levels.
Net flux refers to the balance between the movement of carbon into and out of the atmosphere. Carbon dioxide is naturally exchanged between the atmosphere, land, and oceans through various processes such as photosynthesis, respiration, and decay. These processes can either add carbon dioxide to the atmosphere (positive flux) or remove it (negative flux).
Option 1 states that the net flux of carbon into the atmosphere without considering the contribution from burning fossil fuels is negative. This means that carbon dioxide is being removed from the atmosphere through natural processes, suggesting that there is not an increase in carbon dioxide concentration caused by human activity.
Option 2 states that the net flux of carbon out of the atmosphere without considering the contribution from burning fossil fuels is zero. This implies that carbon dioxide levels remain constant and there is no net increase due to human activity.
Option 3 states that the net flux of carbon out of the atmosphere without considering the contribution from burning fossil fuels is negative. This indicates that carbon dioxide is being removed from the atmosphere by natural processes, suggesting that humans are contributing to the increase in carbon dioxide concentration.
Option 4 states that the net flux of carbon into the atmosphere without considering the contribution from burning fossil fuels is positive. This suggests that carbon dioxide is being added to the atmosphere, providing evidence that humans are contributing to the increase in carbon dioxide concentration.
Based on the provided options, option 4 provides evidence that humans are causing an increase in the carbon dioxide concentration in the atmosphere, as it states that the net flux of carbon into the atmosphere without considering the contribution from burning fossil fuels is positive.