Global warming and its impact: Practice Questions

• a.

  Increased surface temperatures increase the density of tropical waters, causing them to sink faster and speed up the circulation.

• b.

  Higher global temperatures increase the solubility of oxygen in polar waters, leading to faster downwelling in the North Atlantic.

• c.

  Global warming causes the oceans to become more alkaline, which increases the rate of deep-water formation in the Southern Ocean.

• d.

  An increase in glacial meltwater at high latitudes decreases sea water density, potentially slowing the sinking of water masses.

• a.

  Thermal expansion is caused by increased salinity, while melting ice reduces the overall salinity of the ocean.

• b.

  Thermal expansion increases the volume of the existing water mass as it warms, while melting land ice adds new water mass to the ocean.

• c.

  Thermal expansion only affects coastal areas, while the melting of land-based ice affects the deep ocean basins.

• d.

  Thermal expansion occurs only at the poles, whereas the melting of land-based ice occurs primarily in the tropics.

• a.

  As ice melts, the Earth's surface becomes less reflective (lower albedo), absorbing more solar radiation and further accelerating the warming process.

• b.

  As corals bleach, they release large amounts of oxygen, which increases the flammability of the atmosphere and leads to more forest fires.

• c.

  As the ocean warms, it becomes more alkaline, which allows it to absorb even more carbon dioxide, leading to a runaway cooling effect.

• d.

  As sea levels rise, the increased pressure on the sea floor triggers more hydrothermal activity, which releases more methane into the atmosphere.

• a.

  Heat is generated by the friction of ocean currents moving against the seabed.

• b.

  The ozone layer traps heat by reflecting all incoming solar radiation back into space.

• c.

  Greenhouse gases absorb incoming short-wave ultraviolet radiation from the sun.

• d.

  Atmospheric gases absorb outgoing long-wave infrared radiation and re-emit it back toward the surface.

• a.

  Large volumes of fresh water reduce the density of surface water in sinking zones, potentially slowing the circulation.

• b.

  The loss of ice reduces the wind speed, which is the only driver of the deep-water conveyor belt.

• c.

  The ice sheets release large amounts of salt, making the water too dense to sink.

• d.

  The meltwater increases the temperature of the deep ocean, causing it to rise too quickly.

Write your answer out first, then check it against the worked solution.

Write your answer out first, then check it against the worked solution.

Write your answer out first, then check it against the worked solution.