Ice cores, tree rings, paintings/drawings, and global temperature data provide evidence of past climate change: - Ice cores contain air bubbles that allow scientists to estimate past temperatures over 800,000 years and identify climate patterns. However, data is limited to specific locations. - Tree rings indicate past climate conditions, with narrow rings representing cooler periods and wide rings warmer periods. But some tree species do not produce reliable rings. - Paintings and diaries describe visual representations of past climate events but are subjective accounts that are hard to date accurately. - Global temperature records from weather stations and satellites show modern warming of 0.6°C since 1950, but data is limited and station coverage is uneven.

1. Environmental Threats to Our Planet
Paper 2,Module 3

2. Saturday,
24
December
2022 What evidence do we have for climate
change?
Focus Task
How has the climate changed overtime?

3. Key Words
Task: Identify what is
meant by the key
words.
Key Word Definition
Quaternary Period
Ice Age
Climate Change
Inter-glacial
Periods

4. Key Words
Key Word Definition
Quaternary Period The most recent geological period covering
last 2.6 million years, which there were
several cold and warm periods.
Ice Age A glacial episode characterised by lower than
average global temperatures.
Climate Change Changes in long-term temperature and
precipitation patterns. It can be natural or
linked to human activities.
Inter-glacial
Periods
Historic warming periods between glacial
periods, where conditions were similar to
today.

5. What is the
Quaternary Period?
The Earth is believed to be 4.55 billion years old.
The period of time that stretches from 2.6 million
years ago to the present day is called the
Quaternary period.
The entire Quaternary period is often called an ice
age due to the presence of a permanent ice sheet
on the continent of Antarctica.

6. Last 400,000 Years
The human species
evolved about
200,000 years ago
Temperatures have
remained relatively
stable and warmer for
longer Inter-glacial episodes
last approximately
10,000 years; ice
retreats during these
warmer intervals
Glacial episodes last approximately
100,000 years; thick ice expands,
covering vast areas of continents

7. What evidence do we
have for climate change?
Evidence for past climate change can be gathered
from a range of sources including:
-Global temperature data
-Ice cores
-Tree rings
-Paintings and diaries

8. Ice Cores
How can ice cores be used as
evidence for climate change?
How is this a reliable method?
How is this not a reliable method? Oxygen, carbon dioxide and methane in
ice cores can help estimate past
temperature (spanning 800,000 years)
by comparing it against present levels.
Scientists drill deep into the ice in the
Antarctic and Greenland to extract ice
that is thousands of years old.
+ The data is considered to be very
reliable.
- Data only spans the last 800,000
years so it is difficult to compare
beyond that.
- Ice cores are geographically limited.

9. Tree Rings
How can tree rings be used as
evidence for climate change?
How is this a reliable method?
How is this not a reliable method? Each tree ring represents a year of
growth.
Narrow tree rings indicate cooler and
drier past climate conditions.
Wider tree rings indicate warmer and
wetter past conditions.
+ Samples can be easily compared and
dated.
+ Can tell precisely when the tree ring
was created.
- Some trees (birch and willow) can not
be used due to their erratic growth
cycle.
- Alder and pine trees are well known for
missing out tree rings.

10. Paintings and
Drawings
How can paintings and drawings be
used as evidence for climate
change?
How is this a reliable method?
How is this not a reliable method?
Diaries and written observations can
suggest evidence of climate change at
the time such as:
Price increases of grain in Europe. Sea
ice preventing ships from landing in
Iceland. People emigrating due to crop
failures.
+ Provides a visual representation.
- Cave paintings are difficult to date
accurately.
- Personal accounts and art are
subjective viewpoints.

11. Global
Temperature Data
How can global temperature
data be used as evidence for
climate change?
How is this a reliable
method?
How is this not a reliable
method?
NASA use over 1000 ground weather
stations and satellite information to map
global temperature.
Average global temperatures have
increased by 0.6°C since 1950 and
0.85°C since 1880.
-Weather stations are not evenly
distributed (especially in Africa), so
reliability could be questioned.
-Computer programmes are used to
make the global temperature maps, but
this does not make them reliable.
-Data only goes back to 1880.

12. Exam
Question
Describe how ice cores can be
used as evidence of climate
change.
[2]

13. Mark
Scheme
2 x 1 (P) for description of how ice cores can be used as evidence of climate
change.
The layers of ice within the core build up over time and these can be
dated to show past temperatures (1).
The bubbles of trapped gases such as methane can be tested by scientists
(1).
Ice cores allow measurements of carbon dioxide to go further back in
time (1).

14. Exam
Question
Describe the advantages and
disadvantages of using
paintings and drawings as
evidence of climate change.
[4]

15. Resources

16. Evidence of Climate Change
Evidence How is it used? Advantages of
method
Disadvantages
of method
Global
Temperature Data
Ice Cores
Paintings and
Drawings
Tree Rings