Final answer:
The correct answer is option b. Decreased.
Step-by-step explanation:
If the downward slope of the sea ice volume trend line continues, we would expect the sea ice volume in 2020 to have decreased. This is because a downward slope in a graph of sea ice volume over time indicates that there is a negative trend, meaning there is a reduction in volume with each passing year.
1. To estimate the slope of the line of best fit for this dataset, one would take two points on the line (assuming the line is linear) and use the formula (slope = (y2 - y1) / (x2 - x1)), where "y" represents the sea ice volume and "x" represents the year. This calculation would illustrate the rate at which sea ice volume is changing.
2. The data suggests that sea ice extent in the southern hemisphere is showing a reduction over time. When comparing the extended dataset (1980 through 2018) to the data presented from the article, the negative trend in sea ice volume is consistent, indicating ongoing decreases.
3. Data variability refers to how much the data points fluctuate around the trend line. If the range of the data points is wider in later years compared to earlier years, it indicates an increase in variability.
4. One possible reason for the changing variability in sea ice extent could be variations in ocean temperatures, which impact the formation and melting rates of sea ice in different years.
Given the broader context of climate change and its impact on sea ice, glaciers, and snowpack, the consistent loss of ice contributes to global sea level rise. Rising temperatures due to increased greenhouse gas emissions are causing polar ice caps and glaciers to melt, adding to the volume of the oceans and elevating sea levels.