Trees – evaporative cooling and reflection of EM radiation

Calculation: Trees as Air Conditioners

Learning objectives: to apply the equations 

energy for a change of state = mass × specific latent heat

energy transferred = power × time

to a real world situation.

When water evaporates from the leaves of trees, is it called evapotranspiration. The latent heat required for this comes from the thermal store of energy in the surroundings.  This question compares the cooling power of evapotranspiration from an oak tree to air conditioning.

  1. An oak tree can lose up to 400 kg of water through evaporation from its leaves in one day (24 hours). Assuming that the energy for evaporation comes from the tree’s surroundings, calculate the average cooling power of the tree. The specific latent heat of vaporisation of water is 2700 kJ/kg.

energy for a change of state = mass × specific latent heat

400 kg * 2700 kJ/kg  

power  =  energy transferred / time

time = 24*3600

power = 10 kW

  1. An air conditioning unit  has a power of 2.5 kW. How many air conditioning units would be required to provide the same cooling power as the evapotranspiration of one oak tree?

10 kW / 2.5 kW = 4 units

Describe: Trees as Reflectors

Aim: Students should be able to describe the effects of reflection, transmission and absorption of waves at material interfaces.

This activity would work well as a think/ pair/ share activity, and could also be displayed as a poster or other presentation. 

The chlorophyll in green leaves of a tree absorbs the red and blue light in the visible Electromagnetic radiation from the Sun. The green light is reflected. 

A green umbrella would do the same. 

Both cast a shadow on the ground, implying that less visible light reaches the ground. 

The ground also reflects some of the sunlight and absorbs the rest. 

Absorbed sunlight increases the thermal store of energy. 

The greater the thermal energy stored in an object, the more infrared radiation, heat, it emits. 

Would you feel cooler walking along a road that is shaded by trees than you would if you carried a green umbrella?

Both the umbrella and the trees will reduce the amount of sunlight reaching you and warming you up. 

They will also reduce the amount of sunlight reaching the ground. However, the trees are permanent and will have been shading the ground all day, so the ground in the shadow of the trees will be cooler than the ground in the shadow of a moving umbrella. 

The heat, infrared radiation, reaching you from the ground will be lower in the shadow of the trees.

Extended ideas

These could include:

  • evaporative cooling as described above,
  • the fact that the trees will also be a barrier to convection so heat could be trapped near the ground,
  • the fact that trees will be a barrier to the wind and so air will be trapped below them. This will also reduce the conduction of heat from the ground, 
  • in the long term, trees remove carbon from the atmosphere and so reduce the greenhouse effect, 
  • trees can also reduce air pollution,
  • trees can reduce flooding by slowing the flow of water. 

Models for Climate Change

Here is a broad range of simple (ish) climate models suitable for relatively advanced students:

IPCC 2022 – Women and Climate Change

In this resource we will explore the links between two of the Sustainable Development Goals – gender equality, and climate action.

Sustainable development goals 5 and 13

Learning Objectives

  • To be able to explain how Climate Change disproportionately affects women.
  • To be able to give some examples of how women have a crucial role to play in adapting to or preventing climate change

According to the 2022 Intergovernmental Panel on Climate Change Report1  

Climate resilient development is facilitated by developing partnerships with traditionally marginalised groups, including women, youth, Indigenous Peoples, local communities and ethnic minorities

IPCC 20221 SPM.D.2

Salinisation-associated changes may disproportionately burden women responsible for securing drinking water and fuel, such as in the Indian Sundarbans.                 

IPCC 20221, Section 3.5.5.3

Changes in water-related hazards disproportionately impact vulnerable populations such as the poor, women, children, Indigenous Peoples, and the elderly in all locations, especially in the Global South.  

IPCC 20221, Chapter 4

Many countries and social groups most threatened by climate change have contributed the least to the problem and do not have the adequate resources to adapt. Water adaptation policies enabled through ethical co-production between holders of Indigenous Knowledge, local knowledge and technical knowledge; through cooperation and coordinated actions among multiple actors, including women and all marginalized groups, at various levels of governance is needed for effective transitions towards Climate Resilient Development.   

IPCC 20221, Chapter 4

Climate-induced water scarcity and supply disruptions disproportionately impact women and girls. The necessity of water collection takes away time from income-generating activities, child care, and education.

IPCC 20221, section 4.3.3

Although women are often depicted as victims of climate change-induced water scarcity, they are also proactive adaptation actors

IPCC 20221 section 4.8.3

Optional activity – read out these statements and explore what phrases such as water-related hazards, climate resilient development, adaptation, salinisation, Indian Sundarbans etc. mean.

Optional Activity – watch these clips3 from the gender equality day at COP26.

Read this extract from the Malala Fund report2. The Malala Fund is working for a world where every girl can learn and lead.

excerpt from Malala Fund climate change report

Summarise the information in the extract in the following table:

blank table

The Malala Fund estimates that in 2021 climate-related events will prevent at least four million girls in low and lower-middle-income countries from completing their education. If current trends continue, by 2025 climate change will be a contributing factor in preventing at least 12.5 million girls from completing their education each year.

Complete this knowledge organiser using your existing knowledge of extreme weather and climate change :

knowledge organiser

The Mahila Housing Sewa Trust (MHT)’s mission is to organize and empower women in poor communities to improve their habitat.

A quality habitat is a home with all basic services such as clean water, toilets, electricity, and adequate light and ventilation. It is a key financial asset that supports livelihoods, and makes the poor more resilient to heat stress, disease, and other hazards of climate change. Women understand that a strong neighbourhood is essential to upgrading individual homes. They know how to work together to bring much needed services in their under-served communities.

Watch this video:

  1. In Indian slums, why are women more affected by climate change than men?
  2. Why are women better placed than men to lead climate change adaptation?
  3. What simple technology was the woman in the film using to cool her home?

Watch this video

  1. At the edge of the Sahara, what problem were women facing because of climate change?
  2. What did the women do, to solve the problem?
  3. What subsequent benefits has this had for them?

Watch this video

  • For each of the three points made in the film, write a short paragraph explaining how women can make a difference to climate change.

Sources

  1. IPCC, 2022: Climate Change 2022: Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [H.-O. Pörtner, D.C. Roberts, M. Tignor, E.S. Poloczanska, K. Mintenbeck, A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem, B. Rama (eds.)]. Cambridge University Press. In Press. Sixth Assessment Report (ipcc.ch)
  2. A greener, fairer future: Why leaders need to invest in climate and girls education, March 2021, the Malala Fund
  3. COP26 recordings https://unfccc-cop26.streamworld.de/webcast/presidency-event-advancing-gender-equality-in-clim

Core Maths – EVolution of vehicle sales

Resource produced in collaboration with MEI

Brief overview of session ‘logic’

  • Explore the infographic – what can be worked out from this information and what questions does it raise?
  • Look at trends in vehicle registrations
  • Look at proportions of types of newly registered vehicles over time – why has the percentage of petrol cars being registered increased from 2015 to 2020?
  • Do some calculations to show that the number of petrol cars being registered has decreased from 2015 to 2020.
  • Reflect upon the implications for misleading representations of data
  • Consider the implications of the ban on new petrol and diesel cars by 2030 – what affect will this ban have on the proportions of car types being registered?
  • What questions does the increase in electric vehicles raise?

Mathematical opportunities offered

  • Interpretation of data, statistics, graphs, infographics in context
  • Critiquing graphs
  • Reading scales
  • Calculating percentages
  • Exploring proportions of quantities over time
  • Making conjectures about future proportions given available data
  • Analysing and comparing data in order to develop and present a conclusion.
Download the resources
  1. Session plan
  2. Presentation
  3. Student sheet

Key Stage 3 – EVolution of vehicle sales

Resource produced in collaboration with MEI

Brief overview of session ‘logic’

  • Explore the infographic – what can be worked out from this information and what questions does it raise?
  • Look at trends in vehicle registrations
  • Look at proportions of types of newly registered vehicles over time – why has the percentage of petrol cars being registered increased from 2015 to 2020?
  • Do some calculations to show that the number of petrol cars being registered has decreased from 2015 to 2020.
  • Reflect upon the implications for misleading representations of data
  • Consider the implications of the ban on new petrol and diesel cars by 2030 – what affect will this ban have on the proportions of car types being registered?
  •  What questions does the increase in electric vehicles raise?

Mathematical opportunities offered

  • Interpretation of data, statistics, graphs, infographics in context
  • Critiquing graphs
  • Reading scales
  • Calculating percentages
  • Exploring proportions of quantities over time
  • Making conjectures about future proportions given available data
  • Analysing and comparing data in order to develop and present a conclusion.
Download the resources
  1. Session plan
  2. Presentation
  3. Student sheet

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
  • Reading scales
  • 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
  • Reading scales
  • 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

IPCC 2021 – Comparing Arctic and Global temperatures – using Excel

According to the IPCC report for Policymakers “It is very likely that the Arctic has warmed at more than twice the global rate over the past 50 years1.

You are going to test this statement to see if it is true.

Resources

Arctic and global temperatures data spreadsheet

Tutorial: Using Formula in Excel

Tutorial: Creating Line Graphs in Excel

temperature data
  1. Contrast the results of your averages and the range for global air temperatures and those in the Arctic                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
  2. Using the Change over time value in your table consider oif the statement “It is very likely that the Arctic has warmed at more than twice the global rate over the past 50 years” is true.                                                                                                                                                                                                                                                                                                                        
climate change blank graph
  1. Complete the graph above which shows data on Global and Arctic temperature change from 1900 to 2020;
    • Add a title to the graph
    • Draw a curved line of best fit between the data shown for the start of each decade for the Global data
    • Draw a curved line of best fit between the data shown for the start of each decade for the Arctic data
    • Try to predict the future! Continue your line of best fit for both Global and Arctic lines on until 2100. To do so follow the recent tend and try to project that into the future.
    • What could change the future? Think about government policies relating to climate change and the future.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

Why is the Arctic warming faster that the rest of the globe?

Place the following information into a logical sequence to explain why the Arctic is warming faster that the global average:

Sources

  1. IPCC, 2021: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press. In Press. P.3461. Accessed 28th November 2021 at Sixth Assessment Report (ipcc.ch)
  2. Ecochard, K., 2021. NASA – What’s causing the poles to warm faster than the rest of Earth?. [online] Nasa.gov. Available at: https://www.nasa.gov/topics/earth/features/warmingpoles.html Accessed 29 November 2021.
  3. The annual mean global and Arctic  temperature time series are provided by Dr. Muyin Wang. Values are the weighted average of all the non-missing, grid-box anomalies plus the absolute temperature. They are based on the monthly  global gridded data (5×5 grid box ) and the absolute temperature,   that has been developed by the Climatic Research Unit (University of East Angliaand NCAS) jointly with the Hadley Centre (UK Met Office).

IPCC 2021 – Comparing Arctic and Global temperatures

According to the IPCC report for Policymakers “It is very likely that the Arctic has warmed at more than twice the global rate over the past 50 years1.

You are going to test this statement to see if it is true.

temperature data
  1. Contrast the results of your averages and the range for global air temperatures and those in the Arctic                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
  2. Using the Change over time value in your table consider oif the statement “It is very likely that the Arctic has warmed at more than twice the global rate over the past 50 years” is true.                                                                                                                                                                                                                                                                                                                        
climate change blank graph
  1. Complete the graph above which shows data on Global and Arctic temperature change from 1900 to 2020;
    • Add a title to the graph
    • Draw a curved line of best fit between the data shown for the start of each decade for the Global data
    • Draw a curved line of best fit between the data shown for the start of each decade for the Arctic data
    • Try to predict the future! Continue your line of best fit for both Global and Arctic lines on until 2100. To do so follow the recent tend and try to project that into the future.
    • What could change the future? Think about government policies relating to climate change and the future.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

Why is the Arctic warming faster that the rest of the globe?

Place the following information into a logical sequence to explain why the Arctic is warming faster that the global average:

Sources

  1. IPCC, 2021: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press. In Press. P.3461. Accessed 28th November 2021 at Sixth Assessment Report (ipcc.ch)
  2. Ecochard, K., 2021. NASA – What’s causing the poles to warm faster than the rest of Earth?. [online] Nasa.gov. Available at: https://www.nasa.gov/topics/earth/features/warmingpoles.html Accessed 29 November 2021.
  3. The annual mean global and Arctic  temperature time series are provided by Dr. Muyin Wang. Values are the weighted average of all the non-missing, grid-box anomalies plus the absolute temperature. They are based on the monthly  global gridded data (5×5 grid box ) and the absolute temperature,   that has been developed by the Climatic Research Unit (University of East Angliaand NCAS) jointly with the Hadley Centre (UK Met Office).

IPCC 2021 – Impacts of Polar Climate Change

According to the IPCC report for Policymakers “Human influence is very likely the main driver of the global retreat of glaciers since the 1990s and the decrease in Arctic sea ice area between 1979–1988 and 2010–2019 (about 40% in September and about 10% in March). There has been no significant trend in Antarctic sea ice area from 1979 to 2020 due to regionally opposing trends and large internal variability. Human influence very likely contributed to the decrease in Northern Hemisphere spring snow cover since 1950. It is very likely that human influence has contributed to the observed surface melting of the Greenland Ice Sheet over the past two decades, but there is only limited evidence, with medium agreement, of human influence on the Antarctic Ice Sheet mass loss.”1

The Impacts of climate change in Polar regions

Read page 2 of the polar regions fact sheet from the IPCC2.

Produce a spider diagram of all the suggested impacts that are predicted to occur in the Arctic and the Antarctic. Around those impacts suggest some of the negative consequences for humankind.

spider diagram polar climate change
impacts of polar climate change

Sources

  1. IPCC, 2021: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press. In Press. P.10. Accessed 28th November 2021 at Sixth Assessment Report (ipcc.ch)
  2. IPCC.ch. 2021. Regional fact sheet – Polar Regions. [online] Available at: https://www.ipcc.ch/report/ar6/wg1/downloads/factsheets/IPCC_AR6_WGI_Regional_Fact_Sheet_Polar_regions.pdf [Accessed 28 November 2021].
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