1.2.1 Climate Change Flashcards

1
Q

Quaternary period

A

The Quaternary period has lasted for the last 2.588 million years.

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2
Q

Neogene

A

The Neogene period lasted 21.4 million years.

-The Earth was warmer than it is now in the period before the Quaternary period (called the Neogene period).

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3
Q

Within the Quaternary period

A
  • Over the last 300,000 years, there is a cycle between glacial periods and interglacial periods.
  • Glacial periods are cold and last for roughly 100,000 years.
  • Interglacial periods are about 7 degrees warmer on average and last about 8,000-12,000 years.
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4
Q

Within the last 200 years

A
  • Interglacial periods usually last 8,000-12,000 years.
  • 200 years is very small on this timescale.
  • NASA scientists find that the Earth has warmed by 0.8 degrees Celsius since 1880. Most of this warming has happened since 1970.
  • Without changes to our current behaviour, some studies expect the Earth’s temperature to be 4.1°C – 4.8°C higher than in 1880 by 2100, which is 4°C more of warming by 2100.
  • The behaviour of the last 150 years is what we call climate change.
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5
Q

The greenhouse effect

A

-The scientific consensus is that human activities are responsible for the recent increase in global temperatures because they are strengthening the greenhouse effect.
—> The greenhouse effect happens when greenhouse gases (e.g. carbon dioxide, methane) absorb heat that has been reflected off the Earth and re-radiate this heat back towards Earth.

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6
Q

Ice cores showing climate change

A
  • Ice cores can be extracted by drilling into ice sheets.
  • Each year, a new layer of ice freezes onto the top of an ice sheet.
  • Examining the gases in each layer of ice can show us what the climate and temperature were like hundreds of thousands of years ago.
  • Sometimes there are fossils or sediments that can give scientists even more information.
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7
Q

Tree rings showing climate change

A
  • Every year, a new ring forms in the trunks of trees.
  • Rings are thicker in good conditions for growth (temperate and wet climate).
  • Counting the number of tree rings can show that tree’s age.
  • Tree rings give us data on the climate and temperature for up to the last 10,000 years.
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8
Q

Temperature records showing climate change

A
  • Temperatures have been recorded globally since 1850, however, global records are a lot better from the last 50 years.
  • This data is very reliable but only stretches back 170 years.
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9
Q

Pollen analysis showing climate change

A
  • Plant pollen can be preserved in sediment.
  • Comparing plant pollen from sediment and plan pollen from now can indicate what differences have occurred between the current climate and past climate.
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