100 years. Temp increase of 1C in 155 years in 2015. unprecedented rate of warming, must be anthropogenic.
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What is medium term climate change?
1000 years. fluctuations of 0-0.5C eg the medieval warm period followed by the Little Ice Age of 1500-1900
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What is long term climate change?
100,000 years. regular glacial periods of 90,000-100,000 years with intermittent 10,000 year long interglacial periods.
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What is the Earth's natural/normal rate of global warming?
1C in 1000 years.
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define climate
Climate is the average weather conditions of a region over a 30-year period.
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Define climate change
Climate change is any long-term shift in climate as noted by a change in the average values for a climate element such as precipitation. This can involve global cooling as well as global warming.
The use of tree rings to indicate climate. for each year of its life a tree will add one ring to its trunk, the thicker the warmer.
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oldest tree in the world
4000 years so dendrochronology shows medium term climate change
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Why are tree rings not a good indicator?
Rings can also be affected by variations in moisture, CO2 and competition with other plants. 70% of the planet is water so no trees and not all land has them.
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Describe Pollen as evidence for climate change
Undecomposed plants can be found in peat bogs as they hold no air in them. The pollen can be analysed to see where it was from. if it was from a tropical plant but found in a temperate climate, indicates area used to be tropical.
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Describe Ice cores as evidence for climate change
The only long term proxy data. Ice traps CO2 and different oxygen isotopes, allowing us to assess the levels of said gases for 100,000s of years. They can be 3km in depth. most are form antarctica and greenland.
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Where are the oldest continuous ice cores?
123,000 years in greenland and 800,000 years in antarctica.
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Describe ocean sediments.
More O18 is absorbed by coral plants and animals when the oceans are colder. therefore there is more O16 in glacial period ice as a result.
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Describe Glacial evidence
Short term data. a world glacier inventory has been compiled since the 1970's. more than 100,000 glaciers have been tracked by maps and satellites, covering an area of approx 240,000km2
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Describe cardon dating
not a form of proxy data on its own, but helps to find the age of plants up to 50,000 years old by comparison to the known decay rate of C-14
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what is radiative forcing?
when extra greenhouse gases, emitted by humans, heat up the atmosphere by trapping insolation.
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what is the tipping point?
2C
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what is the worst case scenario
4C by 2100
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Other cards in this set
Card 2
Front
What is medium term climate change?
Back
1000 years. fluctuations of 0-0.5C eg the medieval warm period followed by the Little Ice Age of 1500-1900
Card 3
Front
What is long term climate change?
Back
Card 4
Front
What is the Earth's natural/normal rate of global warming?
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