## Core Maths – Extreme Weather

Resource produced in collaboration with MEI

Brief overview of session ‘logic’

• Do reports of extreme cold weather provide evidence that global warming is not happening?
• Show the New York Times graphs of summer temperature distributions for the Northern Hemisphere for different periods.
• Interrogate/critique these graphs
• The distributions of temperatures are approximately Normal distributions and the mean and standard deviation both increase as the time period becomes more recent.
• Use the dynamic bell curve to calculate probabilities of different temperatures in different time periods.
• Despite the mean temperature increasing, the standard deviation also increasing means that the probability of extreme low temperatures increases.
• Normal distributions and bell curves can explain a higher frequency of extreme cold weather despite global warming.

Mathematical opportunities offered

• Interpretation of data, statistics, graphs, infographics in context
• Critiquing graphs
• Using standard form to write very large or very small numbers
• Fitting a Normal distribution or bell curve to a graph
• Exploring the effect of adjusting mean and standard deviation on a bell curve
• Understanding that probabilities can be represented and calculated using areas
• Analysing and comparing data in order to develop and present a conclusion.

## Key Stage 3 – Extreme Weather

Resource produced in collaboration with MEI

Brief overview of session ‘logic’

• Do reports of extreme cold weather provide evidence that global warming is not happening?
• Show the New York Times graphs of summer temperature distributions for the Northern Hemisphere for different periods.
• Interrogate/critique these graphs
• The distributions of temperatures are approximately Normal distributions and the mean and standard deviation both increase as the time period becomes more recent.
• Use the dynamic bell curve to calculate probabilities of different temperatures in different time periods.
• Despite the mean temperature increasing, the standard deviation also increasing means that the probability of extreme low temperatures increases.
• Normal distributions and bell curves can explain a higher frequency of extreme cold weather despite global warming.

Mathematical opportunities offered

• Interpretation of data, statistics, graphs, infographics in context
• Critiquing graphs
• Using standard form to write very large or very small numbers
• Fitting a Normal distribution or bell curve to a graph
• Exploring the effect of adjusting mean and standard deviation on a bell curve
• Understanding that probabilities can be represented and calculated using areas
• Analysing and comparing data in order to develop and present a conclusion

## Is our Weather Becoming More Extreme?

This is a teaching resource linked to section 11.1.4 of the sixth assessment IPCC report of 2021, written with the Royal Geographical Society with IBG. The aim is to answer the question: are we experiencing more weather extremes as a result of climate change?

### Weather and climate

Weather and climate are separate concepts. Weather describes the short-term conditions in the atmosphere, whilst climate refers to its long-term state. Weather measurements might be hourly or daily readings of temperature (°C), rainfall (mm) and wind speed (m/s). Climate is usually defined as the average of 30 years of weather measurements.

### Effects of greenhouse gas emissions and other external forcings

There is now evidence that climatic extremes have changed since the mid-twentieth century — and some of these changes have been the result of anthropogenic influence (if you do not understand the term read What is the Anthropocene? or go to the Natural History Museum webpage on why it matters). Generally speaking, extreme weather events have increased in intensity and frequency since pre-industrial time. In particular, global temperature has increased, both by annual average globally and in localised spikes.

1. Before you begin this resource, define what the words ‘extreme’ and ‘rare’ mean.

The IPCC report says that even with relatively small incremental increases in global warming (as per the SSP1 pathway which holds global warming to 1.5°C) there will be ‘significant changes in extremes’ on the global scale and for large regions. It is:

• Globally, (it is very likely) temperature extremes will continue
• Heavy precipitation will intensify (predicted with high confidence in particular for North America, Europe, and Asia according to the Met Office)
• Tropical cyclones are getting more intense (medium confidence)

The local exchanges of heat and the heat from the evaporation and condensation of moisture, called thermodynamic changes, create temperature extremes. Unprecedented temperatures begin with the initial thermodynamic effect (of a warming troposphere) and lead to increased intensity and frequency of hot extremes. Recently, this has been coupled with decreases in the intensity and frequency of cold extremes.

1. Do you know the different levels of the atmosphere? Sketch planet Earth with the text boxes below in the correct altitude sequence (add aeroplanes, satellites, the aurora borealis, the ozone layer, and the Kármán line to extend the activity).

As Greenhouse Gases (GHGs) increase there is an immediate impact on the temperature of the troposphere, stratosphere, and the surface of the Earth – land, sea and ice. The water vapour cycle intensifies as it becomes easier for water vapour to evaporate from the surface of the Earth and vegetation and for water vapour to condense into cloud droplets in a warmer troposphere. As water vapour is itself a greenhouse gas,  changes in atmospheric water vapour always amplify the initial temperature increases (a positive feedback) whilst the lapse rate[1] feedback also amplifies near-surface temperature increases (positive feedback) in mid- and high latitude countries, such as the UK. This means extreme weather from the larger cumulonimbus clouds and more severe thunderstorms.

[1] A lapse rate describes the rate at which temperature decreases with increasing altitude.

Figure 1 extreme weather and huge waves crashing into Cornwall at high tide © Greg Martin

3. Figure 4 in Appendix A is a feedback diagram on the creation of extreme weather for a typical mid-latitude country. Complete the diagram using the explanation:

The greenhouse effect leads to the temperature of the troposphere and the surface of the Earth rising. With more heat available, evaporation and evapotranspiration rates from surface water and vegetation increases. With more water vapour available in a warmer atmosphere, more clouds can form. As the water vapour condenses, latent heat is released which further heats the atmosphere locally and promotes convection, warm air rising, and the further formation of cumulus clouds. (Latent heat is the energy absorbed by or released from a substance during the change from a gas to a liquid or a solid or vice versa). As a consequence, increased cumulonimbus clouds and thunderstorms creates ultimately causing extreme precipitation events.

4. Now add the processes to the blue connecting lines, using the explainers.

Figure 2 extreme weather will increase both around the world, and specifically in the UK © Greg Martin

Extreme Weather

The IPCC report states that, for each additional 1°C, extreme rainfall will intensify by 7%. Currently annual rainfall on land is increasing and monsoons are changing in complex ways.

5. Analyse Figure 5 in Appendix B. Describe the overview for wet extremes and their potential for human contribution. Reference the areas: NWN and NEC, NEU, SEAF, and SAS.

### Further work

Access the following resources for suggested further work on weather extremes.

### Exam-style question

Using all the work you have completed answer the final question below. The instruction to assess means you should weigh up several opinions to conclude about their effectiveness or validity.

Use the State of the UK Climate 2020 special issue article (in the Further work list above) to inform your answer.

6. Assess whether UK weather is becoming more extreme in the twenty-first century.

Figure 3 big waves crash over the seafront in Penzance, Cornwall © Greg Martin

### Appendix A

Figure 4 a positive feedback loop for extreme weather

### Appendix B

Figure 5 what has been observed in wet extremes around the world? © IPCC report

1. An extreme weather event is defined as ‘an event that is rare at a particular place and time of year’ – a usual definition is an event which happens less than 5% of the time. For example, the warmest 5 July 1st days in London over the past 100 years would be defined as extremely warm. A short-term extreme climate event is ‘a pattern of extreme weather that persists for some time, such as a season.’ Some studies consider an event as extreme if it is unprecedented; on the other hand, other studies consider events that occur several times a year as moderate extreme events.
2. The Earth has 5 major layers. In order from the surface of the planet upwards, they are Troposphere, Stratosphere, Mesosphere, Thermosphere, and Exosphere.
3.

4. All sentences: amplifies temperature increase, stronger convection, more evaporation, and lapse rate feedback amplifies near-surface increases.

5. Overall, the pattern for observed wet extremes around the world is a general increase in the mid and high latitudes, in particular across the US, Europe and Eurasia. There has also been an increase in wet extremes in parts of South America, for example Argentina. The greatest risk region is by far northern Europe (NEU) with a high confidence level that these changes derive from human influence. India (SAS) has also experienced an increase in extreme precipitation with medium confidence from observed trends. Canada (NWN and NEC) and Kenya (SEAF) have a lack of evidence for extreme precipitation.

6. As instructed.

## Increasing Rainfall

As the atmosphere warms, the air holds more water vapour, and this could lead to more intense rainfall events, resulting in an increased flood risk.  In this question, assume every year has 365 days.

The graph shows how the average rainfall (in mm/day) on a rain day at Falmer, Sussex, England has varied with time.

The individual points on the graph show the observed average rainfall in mm/day.

a) What was the observed average rainfall  on a rain day in 2000? Give your answer in mm/day.

[1 mark]

b) In an unrealistic model, a student presumes that every day that year was a rain day. Using this information and your answer to (a) find the total amount of rain that fell in that year. Give your answer in metres, to 2 significant figures.

[2 marks]

For the next questions refer to the line of best fit.

c) Calculate the percentage increase in average rainfall between the years 1939 and 1998.

[3 marks]

d) Calculate the percentage increase in the amount of rainfall between the years 1910 and 1920, and the years 2000 and 2010.

[4 Marks]

## 3D Print the Weather

The RMetS is delighted to have collaborated with CREATE Education to develop instructions to allow schools to 3D print sections of the Central England Temperature Record and use their models to learn about weather, climate, extreme weather and climate change.

These engaging, tactile resources allow students to get a hands-on experience of what climate is and how it can change, and how extreme weather relates to the climate.

The Central England Temperature (CET) data record is the longest instrument record of temperature in the world, with average monthly temperature each month from January 1659 to December 2018.

This project and the accompanying resources allow you to create 3D models that will represent 10 years of temperature data. The models have been designed to interlink, so students can create a series of models to represent larger timeframes. Once the 3D models have been created and 3D printed, there is a tactile resource that can be used in multiple ways in the classroom to visualise and study past weather and climate, and at how the climate of the UK has been changing over time.

The lesson resources specifically focus on

1. The difference between climate and weather

2. The current climate of the UK

3. The changing climate of the UK

4. Looking at past extreme weather events and researching their impacts on people in the UK.

Further resources to teach weather, climate, correlation, photosynthesis, regression, the carbon cycle, isotopes and more.

Further resources past climate change teaching resources for secondary geography.

## Module 4 – The Last 500 years

### Core Resources

Climate graph, 500 years, without uncertainty

Climate graph, 500 years, with uncertainty

## Module 3 – the last 2000 years

### Core Resources

Climate graph, 1,500 years, without uncertainty

Climate graph, 1,500 years, with uncertainty

## Rainforest Deforestation the Carbon and Water Cycles

This news item from NASA relates to this animation, as does this Nature Communication from October 2020.

Suggested learning activities:

Data and GIS exercise for A Level students

Explore leaf area, evapotranspiration and temperature data using various statistical techniques to explore the relationship between deforestation and weather on this resource on the RGS website.

Activity 1:
Ask students to write a voiceover for the film, demonstrating their understanding of the concepts involved.

Activity 2:
Complete this sentence based on the film:
When rainforests are deforested, places downwind are left with more/ less/ the same amount of rainfall and greater/ less/ the same amount of flood risk.

Activity 3:
Look at www.globalforestwatch.org/map and identify a Tropical region which has experienced deforestation in the last decade.
Look at earth.nullschool.net. What is the prevailing wind direction in that region?
Using www.google.com/maps, write a paragraph explaining how you think the water cycle has been affected by deforestation for a place downwind from the rainforest region you identified.

Activity 4:
Having watched the animation, use https://www.globalforestwatch.org/map , http://earth.nullschool.net and https://www.google.com/maps to write a paragraph explaining how you think the water cycle has been affected by deforestation for a specific place downwind and/ or downriver from a rainforest region.

Activity 5:
Having watched the animation, read these articles from Nature and NASA (noting that this predates the Nature article), NASA (2019)Geography Review (p22 – 25) and Carbon Brief.
Summarise the impact of tropical deforestation on the carbon and water cycles.

More information about the water cycle and climate change and the water cycle and an excellent summary from Cool Geography.

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

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

 Resource Subject Suggested age range The Difference between Weather and Climate Teachers’ notes and Worksheet. Geography 11-14 (KS3) The impact of volcanoes on climate Teachers’ notes and Worksheet. Geography 11-14 (KS3) Weather detective – the weather of 1826 Teachers’ notes and Worksheet. Geography 11-14 (KS3) Past Climate Change Teachers’ notes and Worksheet. Geography 11-14 (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 E Geography 11-16 (KS3/4) Solar, Volcanic and Anthropogenic Climate Change Teachers’ notes and Worksheet Geography 14-16 (KS4) The Factors Affecting Photosynthesis Teachers’ notes and Worksheet Biology 11-14 (KS3)

Classroom posters: weather and history recorded by a sample of wood from The Tower of London and The Vyne

Dating the Past Using Stable Isotopes in Tree Rings

Past Summer Rainfall from Oxygen Isotopes in Tree Rings

Unless otherwise stated, all temperature data used in the resources are based on the dataset published in this paper: European summer temperatures since Roman times. More information about the technique can be found in this paper: Oxygen stable isotope ratios from British oak tree-rings provide a strong and consistent record of past changes in summer rainfall.

### Extension Activities

https://ukoak.shinyapps.io/SwanClimv04/

### More Past Climate Teaching Resources

Resources exploring the solar, volcanic, orbital and greenhouse gas causes of climate change over the last 2.6 million years.

Resources based on 3D printed sections of the Central England Temperature record.

Climate change negotiations resource for schools.

Past Climate Change from Weather and Climate: a Teachers’ Guide