Climate change Flashcards
What do Ice cores tell us about climate change?
Scientists drill deep into ice sheets to extract cores of ice up to 2000m in length. By analysing gases when the ice formed and the chemistry of the ice, they can tell what the temperature was each year, and work out how it had changed over time.
What is Dendroclimatology?
Involves looking at annual tree rings – although a tree makes a new ring every year, the width of this ring is not always the same. In wet, warm years, the width of the tree ring is wider. But in cold years, the tree will not grow as much, so the ring will be narrower. Tree rings can reliably show and date climate conditions up to 10,000 years ago.
How do historical records help us understand climate change?
There are many types of historical records such as ancient writings or government reports, that describe the characteristics of the weather and climate. These records can indirectly show different conditions in the past. For example, agriculture reports such as harvest times show changing conditions throughout human history.
Weather condition details have been consistently collected since 1861. Thermometers give reliable but short term record of temperature change.
Name two sources of evidence for climate change
Dendroclimatology (tree rings) Historical records Ice Cores Retreating glaciers Pollen analysis
Why are Retreating glaciers, sediment deposits and sea level change evidence of climate change?
Scientists can tell how big a glacier was and how far it was extended by looking at historical photos and at the position of rocks deposited by the glacier. These rocks can be dated to show when they were deposited. The distance of the rocks from the current glacier indicates climate change. Eg. If the front of the glacier is miles away from the rocks, it indicates that the temperatures have increased over that period.
- When temperatures rise and freshwater ice melts, more water flows to the seas from glaciers and ice caps.
Name 2 natural causes of climate change
Orbital changes - Eccentricity Orbital changes - Axial Tilt Orbital changes - precession (wobble) Solar activity Volcanic activity
How can volcanic eruptions affect the climate?
Violent volcanic eruptions blast huge quantities of ash, gases and liquids in the atmosphere.
Volcanic ash can block out the sun, REDUCING temperatures on the earth. This tends to be short term.
The suns heat is reflected back
out.
How do sunspots affect climate change?
When sunspot activity is at a maximum, the sun gives off more heat (higher temperatures)
When sunspot activity is at a minimum, the solar output is reduced (lower temperatures)
Earth’s Orbital changes are a natural cause of climate change- What is Eccentricity?
Eccentricity describes the path of the earth as it orbits the sun. The earth’s orbit is not fixed – it changes from being almost circular to elliptical (oval) A complete cycle - from circular to elliptical and back to circular again – occurs every 100,000 years.
Orbital changes - Explain how Axial Tilt affects climate change.
The earth spins on its axis, causing night and day. The earth’s axis is currently tilted at an angle of 23 degrees. However, over a period of 40,000 years, the tilt of the earth moves back and forth between two extremes. Closer or further away from the sun.
Name 2 green house gases
carbon dioxide (CO2)
Methane
NITROUS OXIDES
Describe the greenhouse effect
Electromagnetic radiation (the suns energy) pass through the Earth’s atmosphere.
The Earth absorbs most of the radiation and warms up.
The Earth radiates energy as infrared radiation.
Some of the infrared radiation goes into space.
Some of the infrared radiation is absorbed by greenhouse gases in the atmosphere.
The lower atmosphere warms up - causing the earth to warm up.
How does climate change affect agriculture?
Increasing temperatures may make it more difficult to grow crops in certain parts of the world.
Droughts caused by climate change could reduce the amount of water available for irrigation.
Climate change is also likely to cause stronger storms and more floods, which can damage crops. Higher temperatures and changing rainfall patterns could help some kinds of weeds and pests to spread to new areas.
If the global temperature rises an additional 1.5 ̊, U.S. corn production is expected to decrease by 10 to 30 percent.
What does MITIGATION to reduce the causes of climate change mean?
We try to reduce climate change by taking action e.g to reduce/stop the use of greenhouse gases.
Mitigation strategy - International agreements - Explain how they might help mitigate against climate change
World leaders meet to make promises on what action to take to reduce climate change.
The Paris agreement (2016) was signed by 195 parties including the EU. The EU and UK pledged to reduce emissions by at least 40% by 2030.
