U1- Climate Change Flashcards
Define climate.
The average weather over approx. 30 years.
What do you know about glacials?
Glacials lasted longer than inter-glacials. Extremely cold glacial periods were called Ice Ages, where huge ice sheets extended over continents in the Northern Hemisphere.
How do scientists know about past climates?
Scientifically, climatologists can reconstruct past climates by drilling cores through ice and measuring the amount of trapped CO2 in the layers. Evidence shows a strong link between rising climate temp and increased levels of CO2 in the air.
A more vague and less reliable way of reconstructing is to look at written records, old drawings and recorded dates.
Explain ways in which volcanic eruptions can cause climate change.
Give a named example.
Volcanic eruptions produce ash and SO2. If the ash and gas rise high enough, they spread around the stratosphere. This blanket can block and reflect some of the light from the sun and absorb some of the infra-red heat normally reflected back to earth. This cools the Earth short-term.
Large asteroid collisions have a similar cooling effect because they throw dust and ash into the atmosphere.
E.g: Laki eruption in 1783.
Describe how varying solar output can lead to climate change.
Sunspots are darker areas on the Sun’s surface which indicate more solar activity, they appear and disappear.
More spots means more solar output, which will heat the Earth’s climate short-term.
Describe how orbital changes can lead to climate change.
Orbital eccentricity can change the climate long term.
The earths orbit is sometimes circular, sometimes oval-ish.
The Earth’s axis can tilt 1° up or down.
The earths axis wobbles.
These changes effect the amount of solar energy received at the Earth’s surface.
Explain how natural climate change in the past affected people and their lifestyles.
(During the Ice Age)
- The Baltic Sea and most rivers including the Thames froze over in the winter.
- Sea ice reached as far south as Iceland.
- Winters were much colder and longer, reducing the growing season by several weeks.
- These conditions led to widespread famine which wiped out 10-20% of peasant farmers.
- Remote areas such as Greenland were abandoned by settlers.
- The price of grain increased leading to social unrest and revolt.
- Glaciers advanced in the Alps and Northern Europe, overrunning towns and farms in the process.
Define ecosystem.
A unit made up of living things and their non-living environment.
E.g: a pond, forest or desert.
Define extinction.
When a species of plant or animal dies out completely, so none survive.
Give an example of a mass extinction event.
The megafauna were large animals such as the wooly mammoth, sabre-tooth cat and giant beaver which became extinct following the end of the Ice Age (10-15,000yrs ago), when temperatures rose by 5°C in just 1,000 yrs.
In the past, climate change has led to the disappearance of many animal and plant species. Outline why periods of climate change in the past have led to these extinctions.
(Megafauna)
There are two reasons:
- The megafauna could not cope with climate change because they had to migrate to climate which suited them but then failed to find the right foods. Disruption of the food chain.
- Humans migrated to areas near megafauna and hunted them to extinction for their fur, ivory and food.
Describe some of the evidence which tells us climate was different in the past.
- Landforms like U-shaped valleys left by melted glaciers.
- Recorded dates of migration of birds.
- Fossilised animals no longer found in the UK, suggesting reason for migration.
- Samples from ice sheets in Greenland and Antartica.
- Written records such as diaries and newspapers.
Define weather.
The condition of the air around us over a short period of time.
Explain why the UK is said to have a ‘temperate maritime’ climate.
The UK has a temperate maritime climate, meaning it is mild and wet.
This is because all months have significant precipitation, winters are relatively warm and summers are relatively cool.
This is due to the Gulf Stream bringing warm air, the prevailing south-west winds bringing precipitation and the fact that the UK is an island.
Explain what an air mass is.
Air masses are large bodies of air.
They move out of source areas and over the UK bringing warm, cold, dry or moist air.
Using a named example, explain some of the possible impacts of future climate change in a developing country.
Global warming could cause temperatures to rise by 8°C by 2080. In Egypt:
❌Sahara Desert spreading onto areas of farmland, resulting in falling crop yields and less income earned through exportation.
❌Falling crop yields could also lead to famines.
❌Heat waves bringing more illnesses and helping the spread of diseases such as malaria, increasing mortality rate.
❌Less rainfall, resulting in increased water shortages which could lead to water conflict.
❌Rising sea levels flooding 1/3 of Alexandria and 10% of the Nile delta, leaving 7 million people homeless resulting in environmental refugees.
❌Global warming would halt development and developing countries would not be able to cope.
