Upgrade to remove ads
Only $35.99/year

Evidence of climate change

Terms in this set (14)

Climate change
Any significant change in the Earth's climate over a long period. The climate constantly changes, it always has, and it always will
Quaternary period
The most recent geological time period, spanning from about 2.6 million years ago to the present day
Global warming
The term used to describe the sharp rise in global temperatures over the last century (it's a type of climate change)
Earth's climate before the Quaternary period;
Prior to the Quaternary period, the Earth's climate was warmer and quite stable
Earth's climate during the Quaternary period;
During the Quaternary, global temperature has shifted between cold glacial periods that last for around 100,000 years, and warmer interglacial periods that last for around 10,000 years. The last glacial period ended 15,000 years ago and since then the climate has been warming
4 main sources of evidence for climate change;
- Ice cores
- Tree rings
- Temperature records
- Pollen analysis
Ice cores
Cylinders of ice drilled out from glaciers and polar ice sheets
Using ice cores to determine how the Earth's climate has changed;
As ice sheets increase by 1 layer per year, scientists can analyse the gases trapped in each layer to find out what the temperature was each year (the remains of organisms found in cores taken from ocean sediments can also be analysed, extending the temperature record back at least 5 million years)
Tree rings
Rings around a trees trunk that grow once a year, with the thicker they are meaning the more warm and wet the climate was that year
Using tree rings to determine how the Earth's climate has changed;
Scientists can take cores of a tree trunk, count the rings and measure the thicknesses of the rings in order to determine the age of the tree and the climate of each year its been alive (they are a reliable source of evidence of climate change for the past 10,000 years)
Pollen analysis
When pollen from plants get preserved in sediment, e.g. at the bottom of lakes or in peat bogs, and are then analysed
Using pollen analysis to determine how the Earth's climate has changed;
Scientists can identify and date preserved pollen to show which species were living a that time. As scientists know the condition s that plants live in now, preserved pollen from similar plants can show how the climate has changed
Temperature records
Records of temperature over time, e.g. thermometer measurements since the 1850's (which are reliable but short-term) and historical records such as harvest dates and newspaper weather reports (which go back further than thermometer measurements)
Using temperature analysis to determine how the Earth's climate has changed;
Temperature records, such as thermometer readings, can allow us to compare climates accurately over time, however they are relatively short-term and cover a small portion of Earth's history
Students also viewed