IB DP Biology: SL复习笔记4.2.6 Climate Change: Impact

Greenhouse Gases & Climate Patterns

  • Greenhouse gases absorb infrared radiation emitted by the earth, causing the atmosphere to warm
    • Without greenhouse gases, the earth would be much colder
  • The higher the concentration of greenhouse gases in the atmosphere, the more infrared radiation is absorbed, and the warmer the atmosphere will become
  • Increased atmospheric warming has had, and will have, multiple impacts on climate patterns, e.g.
    • Weather events becoming more extreme e.g. hotter, longer, heatwaves, and more violent storms
    • Changes to ocean currents leading to altered local climates e.g. the Gulf stream that currently brings warm water to the west coast of the UK might change direction, causing parts of the UK's climate to cool
    • Warmer air can hold more moisture, leading to changes in patterns of rainfall; more, heavier rainfall in some places could lead to reduced rainfall in other locations
  • Evidence for some of these changes in climate patterns can already be seen in many parts of the world
    • Warming climates cause animals to move towards the poles or to higher altitudes
      • A concern is that these species may not be able to compete with, or may even out-compete, the species already present in these habitats, with either result leading to decreased biodiversity
      • Some species (such as plant species) may not be able to move or change their distributions fast enough to adapt to changing temperatures and may go extinct as a result
    • Polar ice and glaciers are retreating; it is thought that there may soon be no summer ice in the arctic if rates of warming there continue
      • The loss of glacier ice from mountain ranges may affect the water supplies of many people and surrounding wildlife
    • Sea levels have been rising faster in recent years, putting many more people at risk of being flooded out of their homes
      • Sea levels are rising due to the expansion of warmer water and due to melting polar ice