Climate change Flashcards
Quaternary period
The most recent geological time period from about 2.6 million years ago to present day
What was the earth’s climate like before the Quaternary period?
Warmer and quite stable
What has happened with global temperatures during the Quaternary period?
Shifted between cold glacial periods (last about 100,000 years) and warmer interglacial periods (last about 10,000 years)
Global warming
The sharp rise in global temperatures over the last century
4 ways of working out how the climate has changed over time
Ice cores - shows gases trapped in the ice layers
Sea Ice positions - measuring the maximum and minimum amounts of sea ice each year
Diaries & paintings: Historical diaries can show number of days of rain/snow and dates of harvests (early harvest suggests warmer weather) and paintings can show iced lakes etc.
Temperature data - Using thermometers gives a short term record of the temperature data
Reliability of the 4 methods
Ice cores - very reliable and detailed
Sea ice positions - reliable but doesn’t go very far back
Diaries & paintings - Aren’t very reliable as just give a person’s viewpoint
Temperature data - Reliable but short term records and weather stations are not evenly distributed around the world
What are the natural factors that effect climate change?
Milankovich cycles
Sunspots
Volcanic activity
How do Milankovich cycles potentially effect global warming?
Stretch - the earth’s orbit around the sun changes from a perfect circle to an elipse and then back again every 96000 years
Tilt - the earth rotating around the sun is on a tilted axis . This tilt changes over a cycle of about 41000 years
Wobble - the earth wobbles on its axis like a spinning top on a cycle of about 22000 years.
This effects how far the earth is from the sun and the angle at which the suns radiation hits the earth. This could therefore mean that more radiation at certain times therefore creating a warmer climate.
Tilt & wobble also effect how much radiation is received at different latitudes at different times of the year
How do sunspots potentially effect global warming?
Sun spots are cooler areas on the sun and the presence of them increases the sun’s output energy. Therefore when sunspots are reduced not so much energy is given out and the earth can become cooler in some areas. Scientists think that sunspots don’t have a big impact on the earth’s climate
How do volcanoes potentially effect global warming?
The particles ejected from volcanic eruptions reflect the suns rays back out to space causing cooling to the earth.
Volcanic activity may only cause short term changes in climate.
How does the greenhouse effect work?
Solar radiation that reflects back off the earth is trapped due to gases forming a layer around in the atmosphere. this keeps the balance of the earth’s temperature correct
The temperature of the earth is a balance between…
the heat it gets from the sun and the heat lost to space
What is the enhanced greenhouse effect?
Human contribution to the greenhouse effect by
Farming - produces methane from livestock and rice paddies also produce methane when they are flooded
Burning fossil fuels - CO2 is released when burning fossil fuels
Deforestation - Trees chopped down cannot take in CO2 but CO2 is also released in the process of chopping them down
Cement production - Cement is made from limestone which contains carbon. When cement is produced CO2 is released
Environmental impacts of climate change
Ice on land is melting and running into sea causing rising sea levels
Sea ice is melting causing loss of habitats
Species declining due to warming e.g. coral reefs
Precipitation patterns changing due to warming
Distribution and quantity of species changing causing biodiversity to decrease - some species have moved to higher latitudes due to warming and some habitats are being damaged or destroyed
Biodiversity
Variety of plant & animal life in the world or a particular habitat
