Leaves as Thermometers

Leaves as thermometers

Leaf shape changes with climate. Generally smoother leaves are found in warmer climates and more jagged leaves are found in cooler climates.

Because the shape of the leaves change with climate, fossilised leaves are used to help learn about past climates.

By studying different types of plant they can gather climate information, such as annual temperature range and water availability that corresponds to the time when the plant was living.

This graph shows the relationship between the temperature and the percentage of smooth leaves found together:

leaf graph

The main problem with this method is that lots of samples are needed to get a good picture of the past climate. 

Using the graph, work out the approximate mean annual temperature if the following leaves were found together:

 

smooth and jagged edged leaves

This resource was originally developed by the Climate Change Schools Project

Past Climate Changes – Module 4

Using Tree Rings for Past Weather and Climate

Using tree rings to teach weather, climate, past climate change, proxy climate records, correlation, photosynthesis, regression, the carbon cycle, isotopes and more

close up of tree rings

On the BBC news: the research from Swansea University that supports these resources.

1) Show the Film

2) Play the Game

Trees can tell stories about past climates. Scientists can decode the pattern of a tree’s growth rings to learn which years were warm or cool, and which were wet or dry. Scientists combine the ring patterns in living trees with wood from trees that lived long ago, such as the wood found in old logs, wooden furniture, buildings like log cabins, and wooden ships, in order to build a longer historical record of climate than the lifespan of a single tree can provide.

You can decode tree ring data to learn about past climates using the simulation above. Line up tree ring patterns to reveal temperatures in the past. The simulation has two versions. The standard version is the best place to start. The custom version for schools in the United Kingdom was created to go along with a specific curriculum. It has a longer timeline and includes information about some historical events.

The process scientists use to build a climate history timeline has an extra step that, for the sake of simplicity, is not represented in this simulation. When scientists decode long climate records from tree ring patterns, they don’t physically line up the tree core samples next to each other. Instead, they make graphs called skeleton plots for each sample. They combine the skeleton plots from many samples to build a climate history timeline.

Data source for this simulation
The tree ring data in this simulation is from oak trees in southern England. The data, from the UK Oak Project, was collected from living trees, logs in bogs, beams and rafters in old buildings, old wooden furniture, and wall paintings in a farmhouse dating back to 1592. One sample came from the windlass – the wooden crank used to raise and lower a castle’s gate – of the Byward Tower in the Tower of London.

Collect tree ring samples, align the samples to create a 300 year record and see what weather and climate events emerge here.

Alternatively, use the simple paper-strip version from UCAR.

3) Choose the Relevant Teaching Resource

ResourceSubjectSuggested age range
The Difference between Weather and Climate Teachers’ notes and Worksheet.Geography11-14 (KS3)
The impact of volcanoes on climate Teachers’ notes and Worksheet.Geography11-14 (KS3)
Weather detective – the weather of 1826 Teachers’ notes and Worksheet.Geography11-14 (KS3)
Past Climate Change Teachers’ notes and Worksheet.Geography11-14 (KS3)
Correlating Tree Rings and Temperature Notes for Teachers and worksheets A , B, C, D and E and/ or spreadsheets A , B, C, D and EGeography11-16 (KS3/4)
Solar, Volcanic and Anthropogenic Climate Change Teachers’ notes and WorksheetGeography14-16 (KS4)
The Factors Affecting Photosynthesis Teachers’ notes and WorksheetBiology11-14 (KS3)