The causes, effects and responses to climate change Flashcards
Describe the 9 stages of climate change since the last ice age.
- The end of the last ice age was approximately 10,000 years ago.
- The temperature since then has increased by 6°C.
- Within this general trend, however, there have been a number of fluctuations.
- After the last ice age the temperature rose rapidly for the following 2,000 years.
- Between 4,000 and 8,000 years ago, there were two warm periods interrupted by a colder spell.
- Another warm spell happened between the years AD800 and AD1200, which were known as the medieval warm period.
- There then followed the Little Ice Age where temperatures were below the long-term average for 600 years, ending in the 1800s.
- In the past 100 years the temperature has begun to rise steadily, with greater increases since the 1960s.
- The temperature is projected to increase much more rapidly in the coming years, being 5°C warmer in 2100 than it is now.
What are the two external factors that have contributed to climate change since the last ice age?
- Solar output.
2. Orbital geometry.
What are the four internal factors that have contributed to climate change since the last ice age?
- Volcanic activity.
- Surface reflection.
- Change in atmospheric gas.
- Tectonic activity.
How has solar output contributed to climate change (6)?
- This is the energy that comes from the Sun.
- The energy that comes from the Sun changes over time.
- Measurements made in the 1980s showed that the total amount of solar energy reaching the Earth has decreased by 0.1%. Although this is not much, if this trend continues for another 100 years, it could influence global climate.
- It has been predicted that a 1% change in solar output could make the temperature rise or fall by between 0.5°C and 1°C.
- It is thought that the activity of sunspots on the Sun’s surface affects solar output.
- There was a period of drastically reduced sunspot activity between 1645 and 1715, which might have been a cause of the Little Ice Age.
How has orbital geometry contributed to climate change (2)?
- The shape of the Earth’s orbit around the Sun varies 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 it is more elliptical.
- The tilt of the Earth’s axis varies over time from 21° to 24.5°. This variation occurs over a 41,000 year time span. The greater the angle of the tilt, the hotter the summers are and the colder the winters are. When the angle is greater, the Earth usually experiences warmer periods.
How has volcanic activity contributed to climate change (3)?
- Volcanic eruptions release large amounts of sulphur dioxide and ash into the atmosphere.
- These act as a cloak and reduce the amount of solar energy reaching the Earth’s surface.
- In 1815, for example, Mount Tambora erupted. The following year was unusually cold over much of the world, with Europe having heavy snowfalls and frost throughout the summer.
How has surface reflection contributed to climate change (2)?
- During colder periods when there is a larger amount of snow and ice on the Earth, global temperature will drop due to the snow and ice reflecting sunlight back to space.
- If the planet warms up, snow and ice will diminish and the Earth will continue to get warmer.
How has a change in atmospheric gas contributed to climate change?
- There is a clear relationship between the amount of carbon dioxide in the atmosphere and temperature variations.
- Carbon dioxide is one of the most important gases responsible for the greenhouse effect.
- The greenhouse effect keeps heat within the Earth’s atmosphere by absorbing longwave radiation.
- Without the greenhouse effect, the average global temperature of the Earth would be -18°C rather than the present 15°C.
How has tectonic activity contributed to climate change?
- The movement of continents caused by plate tectonics affects the global pattern of atmospheric and ocean circulation.
- The changing shape of the Earth’s surface causes winds and ocean currents to change.
- This process is too slow to have much effect on the climate over the relatively short geological time span of 10,000 years.
How has burning fossil fuels contributed to climate change?
- Fossil fuels are fuels that are produced from coal, oil and natural gas.
- When fossil fuels are burnt, gases are released and build up in the atmosphere.
- The burning of fossil fuels has lead to an increase in greenhouse gases in the atmosphere.
- In China, 75% of energy is produced from coal.
For what 2 reasons has there been an increase in the burning of fossil fuels?
- Car ownership has increased.
2. There has been an increase in energy producers.
What is methane (2)?
- Methane is a greenhouse gas, which means that it can trap heat within the Earth’s atmosphere.
- It makes up 20% of the greenhouse gases in the atmosphere and is 20 times more potent than carbon dioxide.
What 6 places does methane come from?
- Wetlands including marshes and swamps.
- The growing of rice.
- Landfills that contain rotting vegetable matter.
- Burning vegetation.
- Fossil fuel mining.
- The bowels of animals.
By how much have the levels of methane in the atmosphere been increasing by for the past decade?
There has been an increase of 1.5% a year.
For what 4 reasons have the levels of methane in the atmosphere been increasing?
- There has been an increase in the mining of fossil fuels.
- Temperature has been rising, which causes an increase in bacteria emissions from wetlands.
- There has been an increase in rice production due to the growing population in rice producing countries.
- There has been increase in the number of cattle and sheep for meat reflecting an increase in Western-style diets.
What is carbon dioxide (4)?
- Carbon dioxide is a greenhouse gas, which means that it can trap heat within the Earth’s atmosphere.
- It is the main gas released by burning fossil fuels.
- About 3/4 of carbon dioxide emissions come from the combustion of fossil fuels for heating, transportation and power generation.
- Carbon dioxide concentration in the atmosphere is quite low at just 0.04%.
What 5 places does carbon dioxide come from?
- Respiration of all living organisms.
- Combustion.
- Volcanic eruptions.
- Combustion of organic matter.
- Fermentation by microbes.