Polar Ice and Ocean Currents.
Researchers have determined that the melting of polar ice is accelerating. While it is normal for some of the ice to melt in the spring and summer, measurements indicate that melting is now occurring earlier in the spring. The ice is re-freezing later in the fall and winter, as well. Scientists believe water temperatures have increased due to global warming.Sea ice is the portion of polar ice that floats in the ocean (instead of being on land). In the Northern Hemisphere, sea ice has been melting so quickly that many scientists think there will be no Arctic sea ice in the summers by the later part of this century.Ocean currents are "conveyor belts" of water that move far below the surface of the world's oceans. These bands of water move cooler water from the polar regions toward the equator, and they move warmer water back toward the poles. Scientists believe this helps to control the Earth's climate.Polar ice and ocean currents are directly connected. As the polar ice melts, it changes the density of the sea water in the region. This reduces the ability of the sea water to sink, which is necessary for the ocean currents to continue to flow. Because of the rapid melting of sea ice, many researchers are concerned that the ocean currents could slow or even stop working entirely.The article included a graph to represent the total area of sea ice, measured in millions of square kilometers, floating in the Arctic Ocean in the Northern Hemisphere.
11. Which one of the following graphs does the BEST job of representing the change in total sea ice over the past several decades?(1 point)