changing climate Flashcards
(35 cards)
What is the Quaternary Period?
- The most recent geological time period
- 2.6 million years ago to the present day
What was the climate like before the Quaternary Period?
- The Earth’s climate was warmer and quite stable
What was the climate like during the Quaternary Period?
- Global temperatures shifted between cold glacial periods (100,000 years) and warmer interglacial periods (10,000 years)
How has the climate changed since the Quaternary Period?
- The last glacial period ended around 15,000 years ago
- Since then the climate has been warming
What is global warming?
- Term used to describe the sharp rise in global temperatures over the last century
- Type of climate change
How do ice cores give evidence for climate change?
- Ice sheets are made up of layers of ice - one layer is formed each year
- Scientists drill into the ice sheets to get long cores of ice
- By analysing the gases trapped in the layers of ice, they can tell what the temperature was each year
- Data collected from ice cores is very detailed and reliable
How does temperature data give evidence for climate change?
- Since the 1850s, global temps have been measured using thermometers
- Gives a reliable but short-term record of temperature change
- Weather stations are not evenly distributed - data is patchy
How do diaries and paintings give evidence for climate change?
- Historical diaries can show what the climate was like in the past
e.g. giving the number of days of rain, and the dates of harvest (early harvest suggests warm weather? - Paintings of fairs and markets on frozen rivers show that winters in Europe were much colder
- Not very reliable, gives one person’s viewpoint
How do sea ice positions give evidence for climate change?
- Sea ice forms around the poles in winter (when ocean temps fall below 1.8°C)
- Melts during the summer (when it’s warmer)
- By observing maximum and minimum extent of sea ice each year, can tell how ocean temps are changing
- Data is very reliable, however, accurate records don’t go far back
What are some natural factors that possible cause climate change?
- The Milankovitch Cycle
- Sunspots
- Volcanic activity
What is eccentricity and how does it cause climate change?
- The path of the Earth’s orbit around the Sun
- Earth’s orbit changes over time from being circular to mildly elliptical
- Complete cycle occurs about every 100,000 years
- Circular means colder periods
- Elliptical means warmer periods
What is axial tilt and how does it cause climate change?
- The Earth spins on its axis causing night and day
- Over a period of 41,000 years axial tilt moves between 21.5° and 24.5°
- The greater the tilt the higher the temp
What is precession and how does it cause climate change?
- The Earth’s wobble
- Complete cycle 26,000 years
- Accounts for long days and long nights
What are sunspots?
- Sunspots are cooler areas of the Sun’s surface that are visible as dark patches
- They increase the Sun’s output of energy
- Cycles of about 11 years
How do sunspots possibly cause climate change?
- Periods where there are very few sunspots, solar output is reduced
- Cause the Earth’s climate to become cooler in some areas
- Most scientists think that it doesn’t have a major effect on global climate change
How does volcanic activity cause climate change?
- Eject large quantities of material into the atmosphere
- Sulphur dioxide reflects the Sun’s rays back out to space, so the Earth’s surface cools
- Ash blocks the Sun reducing surface temperatures (called volcanic winter)
What is the greenhouse effect?*
- heat from the sun
What is the enhanced greenhouse effect?
- Human activities are causing global warming by making the greenhouse effect stronger
How does farming contribute to the greenhouse effect? *
- Farming of livestock produces ethane
- Flooded fields of rice paddies emit methane
How does burning fossil fuels contribute to the greenhouse effect? *
- When fossil fuels like coal, oil, natural gas and petrol are burnt, CO2 is released into the atmosphere
e.g. thermal power stations
How does deforestation contribute to the greenhouse effect? *
- Plants
How does cement production contribute to the greenhouse effect? *
- cement
What the environmental impacts of climate change?
- Temps expected to rise by 0.3 - 4.8 °C between 2005 and 2100.
- Warmer temps causing glaciers to shrink and ice sheets like Greenland to melt.
- Melting of ice on land means that water stored on land as ice returns to the oceans, - causes sea level rise, lead to low-lying and coastal areas being flooded more regularly.
- Sea ice shrinking - loss of polar habitats.
- Other species declining due to warming, e.g. some coral reefs suffering from bleaching due to increasing sea water temperatures.
- Precipitation patterns changing - warming is affecting how much rain areas get.
- Distribution and quantity of some species could change and biodiversity could decrease:
- some species now found in higher latitudes due to warming temperatures.
- some habitats are being damaged or destroyed due to climate change
species that are specially adapted to these areas nay become extinct
What are the economic impacts of climate change?
- Weather is getting more extreme - more money spent on predicting extreme weather events (e.g. floods, droughts and tropical storms), reducing their impacts and rebuilding after them.
- Rising temps are causing areas of permafrost to melt - lead to the collapse of buildings. Pipelines etc. built on it.
- However, it’s easier to extract natural resources
- Globally some crops have suffered from climate change (e.g. maize crops have got smaller due to warming in recent years.
- But some farmers in high-latitude countries are finding that crops benefit from warmer conditions.
- Water shortages affect our ability to generate power
- hydroelectric power and thermal power stations require lots of water