Name some natural causes of climate change
- asteroid collisions
- orbital changes
- volcanic activity
- variations in solar output
How can asteroids collisions cause climate change?
Large asteroid collisions can cause cooling as material blocks out the Sun. Asteroids hitting Earth can cause huge fires which release massive amounts of CO2 which subsequently has a warming effect.
How can orbital changes cause climate change?
The Earth’s orbit changes a small amount once every 100,000 years. These are known as Milankovitch cycles. When the Earth does a more circular orbit it gets warmer whilst when the Earth does a more elliptical orbit, it gets cooler because it is further away from the sun.
How can volcanic activity cause climate changes?
Volcanic eruptions pump ash dust into the atmosphere (blocking out sunlight) causing a cooling effect.
How can variations in solar output cause climate change?
The amount of energy radiated from the Sun changed over and 11-year cycle. Sunspot activity raises global temperature.
What was the Little Ice Age and what were the effects on people?
- a colder period in northern Europe starting in the 15th century and lasting to the mid 19th century
- crops did not grow well which meant less food
- the winters were very cold and the summers short
What are sunspots?
Sunspots were first recorded over 2000 years ago. These are black areas on the Sun. Lots of spots mean more solar energy is being fired out from the Sun towards Earth.
Cooler periods, such as the Little Ice Age, and warmer periods, such as the Medieval Warm Period, may have been caused by changes in sunspot activity.
What could be the causes of the Little Ice Age?
- fewer sunspots
* volcanic ash in the atmosphere
What is the evidence for the Little Ice Age?
- diaries, newspapers and paintings
* the tree rings in old trees are thinner during cold year
What was the impact of climate change on megafauna?
Megafauna (e.g. Mammoths, giant beavers, save-toothed Tigers) had evolved during the Ice Age.
The Ice Age ended and temperatures rose 5°C in 10,000 years
The megafauna couldn’t adapt to the warmer climate and became extinct. Hunting by early humans could also have been a factor in their extinction.
When did megafauna become extinct?
The mass extinction of megafauna happened at the end
of the Quaternary Period.
Why does the climate of the UK appear to be changing?
- The climate of the UK appears to be changing as a result of global changes caused by human activity.
- The North Atlantic current is likely to move which will probably reduce sea temperatures and bring less rainfall
- more air masses will come from the north, bringing more storms and perhaps more extreme cold in winter
- The paths of depression (which bring rain) main be altered by these changes in air masses and ocean currents
What factors affect the UK’s climate?
- Latitude affects how much Sun the UK gets and how strong it is during different seasons
- The North Atlantic current/drift keeps the UK warmer that other places of the same latitude
- Air masses bring weather conditions with them from where they originated. The UK is affected by 5 air masses
- The prevailing winds are from the Atlantic Ocean in the south west. They pick up moisture from the sea and often bring rain to the UK
Describe the climate of the UK
The climate of the UK is mild (cool) and wet. it is described as temperature maritime.
How do human activities produce rising levels of carbon dioxide and methane and how do these contribute to the enhanced greenhouse effect?
More CO2 is produced because:
- there us more industry
- more energy is needed so more fossil fuels are burnt
- transport increases so more oil is burned as petrol and diesel
- land is needed so there is deforestation, trees are often burnt
More methane is produced because there is more demand for meat so there is more demand for meat so there are more form animals
These contribute to the enhanced greenhouse effect as more greenhouse gases are trapped inside the atmosphere, making the Earth warmer
Consider a range of projections for global temperature change and sea level rise, including reasons for the uncertainty.
People are uncertain about climate change predictions because they are not certain if things like the amount of CO2 will rise. if it does, global temperatures could rise by 6°C but if it doesn’t global temperatures will only rise by a maximum of 2°C.
The oceans are rising by 9mm per year due to glaciers melting because of rising temperatures and this could result in low-lying areas being flooded e.g. the UK
What are the environmental impacts of climate change in the UK?
- Sea level rise will lead to the loss of coastal land and increased erosion. Risk of low-lying cities flooding, e.g. London
- More severe storms and longer summer draughts
- Changes to fishing industries if fish species move to different waters
- Ecosystem change could mean some plant and animal species move into new areas and new (invasive) species emerge
- Warmer temperatures could encourage diseases such as malaria
What are the economic impacts of climate change in the UK?
- An increase in refugees from other countries hit hard by climate change coming to the UK
- Warmer weather may mean farmers can grow different crops and enjoy a longer growing season
- Hotter summers could mean more people have holidays in the UK (so less air travel overseas)
- Damage to cities such as London from flooding would be extremely expensive and very disruptive
- Cost of protecting places from flooding will be expensive and in some cases not practical
- Housing design might be need to be altered so that less water is wasted and higher temperatures are dealt with
