enhanced greenhouse effect and global climate change

• Global climate change involves changes to the composition of the atmosphere that alter energy processes , the climate and the physical and biological processes they control . Changes resulting from human activity are known as anthropogenic changes.
• Human activities are increasing the concentration of the greenouse gases that absorb infrared radiation and warm the atmosphere . Some are gases that naturally occur n the atmosphere while others are only released by human activities .
• human activities which increase atmospheric concentration :

  • Carbon dioxide : combustion of fossil fuels and wood planning .
  • methane : anaerobic respiration y microbes in padi fields , produced during the formation of fossil fuels
  • oxides of nitrogen : oxygen and nitrogen from the air then react at high temperatures in locations such as  vehicle engines they are then realised into the atmosphere as exhaust gases
  • chlorofluorocarbons
  • tropospheric ozone
• consequences of global climate change : the relatively small temperature increases involved in climate change may have a range of direct and indirect impacts on the abiotic and biotic conditions on earth.
• ecological changes : global climate change may result in changes in species survival caused by altered abiotic factors such as temperature and water availability
• Ecological change examples :

  • Species may be affected directly by the temperature , by changes to other species they rely on by changes to natural processes that affect them.
  • Temperature rise may cause plants to grow faster , this could cause more food for herbivores such as butterfly and caterpillar .
  • The timing of ecological events such as flowering , migration and nesting may change . Survival of interdependant species may be reduced ,for example, if pollinating insects emerge earlier then when the flowers have grown
• the species most likely to be affected are those that are closest to the edge of their range of tolerance. some species may be unaffected by changes in the physical environment , but other species rely on may be there could a change in food supply ,predation , disease , or the survival of pollinators , or seed-dispersal .
• bats in the UK : climate change may affect bats in the UK in positive and negative ways . warmer , shorter inters may increase survival during hibernation . warmer weather may increase the populations of food species , especially night-flying insects . wetter , stormier weather may reduce the time for which bats can feed , which may reduce survival .