Environmental Threats to Our Planet Flashcards
1
Q
What is the Quaternary period?
A
- The most recent period in geological time is known as the Quaternary.
- The Quaternary period started 2.6 million years ago and extends up until the present
- Within it there have been two epochs the Holocene and the Pleistocene
2
Q
How has the climate changed from the beginning of the quaternary period to the present day?
A
- During the quaternary period the quaternary period temperatures have fluctuated wildly, although there has been a gradual overall cooling
- In the Quaternary period there have been glacial periods and inter-glacial periods
3
Q
What are the key periods of warming and cooling since 1000AD?
A
- The Medieval Warm Period
- The Little Ice Age
- Modern warming
4
Q
What was the medieval warming period?
A
- The Medieval Warming period (MWP) lasted from about 950 to 1250 and was a time of warm climate in the North Atlantic region.
- Temperatures in some regions of the world were the same or higher than recent temperatures, but on average, the global temperature was cooler than it is now
5
Q
What was The Little Ice Age?
A
- The Little Ice Age was between 1300-1870
- It is the name given to a period of time when parts of Europe and North America experienced much colder winters than today
- The coldest period were in the fifteenth and seventeenth centuries
6
Q
What were the effects of The Little Ice Age?
A
- The price of grain increased and vineyards in much of Europe became unproductive
- Sea ice engulfed Iceland, preventing ships from landing. As cros failed many people decided to emigrate.
- Iceland lost half its population during the Little Ice Age
- The sea froze around parts of the UK and regular winter ‘Forsy Fairs’ were held on the frozen river Thames
- Throughout Northern Europe, rivers froze and peole suffered from intensly cold winters when food supplies were limited
- Despite these harsh climatic conditions European culture and technology flourished
7
Q
What is Modern Warming?
A
- In the last few decadews average temperatures has increased drastically. This current warming trend has become known by the term Global Warming
- Scientists consider tjay the rapid rise in temperatures since the 1970s can be linked to human activities, such as burning fossil fuels, deforestation and waste disposal
8
Q
What is the evidence for climate change?
A
- Global temperature data
- Ice Cores
- Tree ring data
- Paintings and Diaries
9
Q
How is Global Temperature data evidence for climate change?
A
Weather stations (which are not evenly distributed across the world, especially in Africa) have been used to produce to Global maps showing temperature but they have a fairly sparse network which does nto make them absolutely accurate and reliable
10
Q
How do tree rings give evidence for climate change?
A
- Every year the growth of a tree is shown by a single ring.
- If the rinf is narrow it indicates a cooler, drier year
- If the ring is thicker it means the temperature was warmer and wetter
- Theses patterns of growth are used to produce tree ring timescales, which get accurate climate information
11
Q
How do Ice cores give evidence for climate change?
A
- Ice cores extracted from the Antarctic and Greenland ice sheets have proved to be an important source of information about past global temperatures
- When snow falls in cold polar enevironments each year it gradually builds up layers every year the buiried layers of snow are compressed and gradually turn to ice
- Scientists are able to drill deep into the ice to extract cylindrical cores from ice that is many thousands of years old. The layers of ice within a core can be dated accurately by analysing the trapped water molecules, scientists can calculate the temperature of the atmosphere when the snow fell
12
Q
How are Paintings and Diaries used to provide evidence for Climate Change?
A
- Historical records, such as paintings and diaries, can provide additional evidence of climate change
- Ancient cave paintings of animals in France and Spain depict nature as it was 40,000 and 11,000 years ago, a period of time where climate changed significantly. The problem is dating them accurately
- Much of evidence of the little ice age comes from diaries and written observations made at the time
13
Q
What are the different theories of causes of climate change?
A
- Natural: Variations in energy from the sun
- Natural: chanegs in the earth’s orbit
- Natural: Volcanic Activity
- Human: responisble for the enhanced greenhouse effect contributing to global warming
14
Q
How does changes in the Earth’s orbit cause climate change?
A
- The Milankovitch cycles are cyclical time periods that relate to the Earth’s orbit around the sun
- Scientisrts belive that these cycles affect the timings and seasonality of the Earth’s climate
- The 100,000 year eccentricity cycle coincides closely with the alternating cold (glacial) and warm (inter-glacial) periods in the Quaternary period
15
Q
How does volcanic activity cause climate change?
A
- Sulfur dioxide is produced from volcanic eruptions
- Sulfur dioxide can lead to long term cooling
- The fine aerosols that result from the conversion of sulfur dioxide to sulfuric acid act like tiny mirrors reflecting radiation from the Sun
- This results in the cooling of the lower atmosphere
- The most recent example of this was the eruption of Mount Pinatubo in the Philippines on 15 June 1991
- The aersols produced from the volcano cooled the world’s climate for a period of three years by up to 1.3oC
