Challenges for the Planet 2

Challenges for the Planet 2

1. External factors which effect climate change.

   • Solar Output
     • This energy comes from the sun
       • Measurements made in the 1980's showed that the total amount of solar energy reaching the Earth has decreased by 0.1%
         • Although this does not seem like much, however over 100 years it could influence global climate.
           • Its been predicted that a 1% change in solar output could make the temperature rise or fall between 0.5-1 degrees celcius.
             • It is thought that the activity of sunspots can affect solar out put. There was a period of drastically reduced sunspot activity between 1645 and 1715 which may have been the cause of the 'little' ice age.
   • Orbital Geometry
     • Orbital characteristics that are responsible for past and possible future climate changes include
       • 1. The shape of the Earth's orbit changes from nearly circular to elliptical and back to circular again every 95,000 years. Cold, glacial periods have occurred when the Earth's Orbit is circular and warmer periods when its more elliptical.
         • 2. The tilt of the Earth's axis varies over time from 21.5 and 24.5 degrees. This variation occurs over a 41,000 year time span. The greater the angle of the tilt, the hotter the summers and the colder the winters are.

2. Internal factors which affect climate change.

   • Surface Area Reflection.
     • During cooler periods when there is a larger amount of snow and ice the global temperature will drop due to snow and ice reflecting sunlight back to space. If the planet warms up the snow and ice will melt and it will allow the Earth to get even warmer.
   • Volcanic Activity
     • Volcanic eruptions release large amounts of sulphur dioxide and ash into the atmosphere. These act as a cloak and reduce the amount of solar (radiation) energy reaching the Earth's surface.
       • EXAMPLE: Laki eruption, in Iceland 1783, reduced global temperatures and lead to harvest failing in West Europe
   • Change in atmospheric gas.
     • There is a relationship between the amount of carbon dioxide in the atmosphere and temperature variations. Carbon dioxide is the most important gas responsible for the greenhouse effect.
       • The greenhouse effect keeps heat within the Earth's atmosphere, so if there is an increase of carbon dioxide there will be an increase in temperature. Likewise if there is a decrease in carbon dioxide there will be a decrease in temperature.
   • Tectonic Activity
     • The movement of continents caused my plate tectonics affects the global pattern of atmospheric and ocean circulation; and the changing shape of the Earth's surface causes winds and oceans currents to change.
       • This process is very slow and to have much of an effect on the climate over the relatively short geological time span of 10,000 years.

3. Modern Methane comes from a variety of sources

   • Wetlands including Marshes and Swamps
     • The growing of rice- rice dependant diets
       • Landfills which contain rotting vegetable matter
         • Burning vegetation
           • The bowels of animals (meat dependant diets)

4. The levels of methane in the atmosphere have been rising by 1.5% a year for the past decade. This is due to:

   • An increase in the mining of fossil fuels
     • Rising temperature, which causes an increase in bacteria emissions from wetland
       • An increase in the production of rice due to growing population in rice producing countries (rice dependant diets).
         • An increase in the number of cattle and sheep for meat reflecting an increase in Western-style diets (meat dependant diets)

5. The negative effects of climate change.

   • Changing Pattern of Crop Yields
     • Countries closest to the equator are likely to suffer most as their crop yields will decrease. In Africa, there are longer periods of drought and shorter periods of growing seasons.
       • They could lose a third of their crop yield due to this.
         • It is forecast that in India there will be a 50% decrease in the amount of land available to grow wheat, this is due to hotter, dryer weather.
   • Rising sea levels
     • Research published in 2007 showed that between 1993 and 2006 sea levels rose 3.3 mm a year
       • This will lead to a 88cm rise in sea levels by the end of the century.
         • The rise will threaten large areas of low lying land. This can lead to people having to evacuate their homes because they are engulfed by the sea.
   • Retreating Glaciers
     • The majority of the worlds glaciers are retreating. This is thought to be due to the increase in temperature due to climate change.
       • Research has shown that 90% of the glaciers in Antarctica are retreating. The melting glaciers at the poles could also have an effect on ocean water movement.

6. The Responses to change at a global scale

   • Kyoto Protocol
     • In June 1992 the UN held a meeting in Rio Je Janeiro called the Earth Summit
       • The result of the meeting was the first international environment treaty which aimed to stabilize greenhouse gas emissions.
         • From this came the Kyoto Protocol. Countries that signed (singed in 1997) agreed to cut greenhouse gas emission by 5.2% compared with 1990 levels globally.
           • By 2008, 181 countries had signed the Kyoto Protocol. In December 2007 a further Climate Change conference took place in Bali.
             • The result of the meeting in Bali was the Bali Roadmap in which initiatives were agrees to try to reach a secure future climate.