GCSEScienceAQACombined Science: TrilogyPhysicsRevision NotesEnergyNational & Global Energy ResourcesEnvironmental Issues

Environmental Issues (AQA GCSE Combined Science: Trilogy: Physics): Revision Note

Exam code: 8464

Leander Oates

Written by: Leander Oates

Reviewed by: Caroline Carroll

Updated on

AQA Combined Science: Trilogy: PhysicsAQA Physics

Environmental Issues

  • The current evidence for climate change is overwhelming – in order to limit global warming, carbon dioxide emissions must be limited globally

  • Doing so, however, requires a balanced approach – carbon-neutral energy resources either lack public support, reliability or cannot produce sufficient energy to meet the demand

  • Nevertheless, over the past 20 years, there has been a gradual shift towards cleaner technologies

    • Government grants have encouraged the development of wind and solar farms

    • Coal has gradually been replaced with cleaner natural gas

    • A new generation of nuclear power stations are currently in development – although with old power stations being shut down, nuclear power is becoming a smaller option

  • Further reduction of carbon dioxide emissions will require some further measures:

    • More nuclear power stations will be needed to replace existing fossil fuel stations

    • A means of storing energy from unreliable sources (such as solar and wind) will need to be developed

  • Although science can identify environmental issues arising from the use of energy sources, political, social, ethical and economic considerations must be taken to deal with these issues

Examiner Tips and Tricks

Write 'carbon dioxide', not 'carbon emissions' or 'greenhouse gases'. These are not enough on their own to score. Name the gas and link it to the effect, for example carbon dioxide causes global warming

Sources of UK electricity in 1990 and 2019

Two pie charts comparing the sources of UK electricity in 1990 and 2019. In 1990: coal 75%, nuclear 19%, imports 4%, renewable 2% and gas less than 0.1%. In 2019: gas 38%, renewable 35%, nuclear 17%, imports 8% and coal 2%

  • In the past 30 years in the UK:

    • Fossil fuels' share of electricity generation has dropped from about 75% to 40%

    • Renewables' share of electricity generation has increased from 2% to 35%

  • Coal used to be the main provider of energy in the UK, but now it is natural gas

    • This is because, out of the three main fossil fuels, coal produces the most carbon dioxide, while natural gas produces the least

    • Switching to gas is not the solution to reducing carbon dioxide emissions, but as the use of carbon-neutral energy resources increases, it is a step in the right direction

Examiner Tips and Tricks

When a question gives a graph of temperature or carbon dioxide against time, state the overall trend and quote the time period or a pair of values, for example 'mean sea surface temperature increased from 16.45 °C to 16.96 °C between 1988 and 2016'. Say if the trend levels off or if the two graphs differ

The Greenhouse Effect

  • Global warming is caused by an increase in the greenhouse effect

  • Greenhouse gases in the atmosphere (mainly carbon dioxide and methane) absorb infrared radiation and keep the Earth warm

  • Burning fossil fuels releases extra carbon dioxide, so more infrared radiation is absorbed and the Earth's average temperature rises

Diagram of the greenhouse effect. Rays from the Sun pass through the atmosphere and are absorbed by the Earth's surface, which re-emits the energy as infrared radiation of longer wavelength. Some infrared passes through the atmosphere into space, and some is absorbed by carbon dioxide, a greenhouse gas, and re-emitted in all directions, including back towards the Earth, so the Earth becomes warmer

  • The process of global warming is as follows:

    • The Sun emits radiation (mostly visible light) that passes through the atmosphere and warms the Earth's surface

    • The warm surface emits infrared radiation

    • Some of this infrared radiation escapes into Space

    • Some is absorbed by greenhouse gases, which then emit it again in all directions, including back towards the surface

    • This keeps more energy in the atmosphere and the Earth's average temperature rises

    • The higher the concentration of greenhouse gases, the more infrared radiation is absorbed and the higher the average temperature

  • Once the temperature increases too much, this will lead to devastating consequences:

    • Climate change due to the increase in Earth’s temperature

    • Sea levels will rise as glaciers melt because of high temperatures, causing flooding in low-lying countries

    • Extinction of species due to the destruction of natural habitats

    • Migration of species (including humans) as they will move to areas that are more habitable (with no droughts or recurring wildfires)

    • Spread of diseases caused by warmer climate

    • Loss of habitat due to climate change (animals that live on glaciers)

  • Many of these consequences have already begun to take effect

Examiner Tips and Tricks

Exam questions on this topic commonly ask you to link a pollutant to its effect. Make sure you know the following:

  • Carbon dioxide causes global warming (it does not damage the ozone layer or cause acid rain)

  • Sulfur dioxide causes acid rain

  • Particulates cause global dimming

  • Nitrogen oxides cause breathing problems or acid rain

Unlock more, it's free!

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

I would just like to say a massive thank you for putting together such a brilliant, easy to use website.I really think using this site helped me secure my top gradesin science and maths. You really did save my exams! Thank you.

Beth
IGCSE Student

This website is soooo useful and I can’t ever thank you enough for organising questions by topic like this. Furthermore, the name of the website could not have been more appropriate as it literally did SAVE MY EXAMS!

Fathima
A Level Student

Incredible! SO worth my money, the revision notes have everything I need to know and are so easy to understand. I actually enjoy revising! It makes me feel a lot more confident for my GCSEs in a few months.

Kate
GCSE Student

Absolutely brilliant, both my girls used it for A levels and GCSE. It's saves on paper copies, also beneficial exam questions ranked from easy to hard. It's removed a lot of stress from the exams.

Sameera
Parent

Just to say that your resources are the best I have seen and I have been teaching chemistry at different levels for about 40 years

Mark
Chemistry Teacher

Excellent

Our rating represented in Trustpilot stars
Read more reviews

Build on this topic

Check your understandingTry an Exam Question on this topicTest your recallReinforce key facts and definitions with Flashcards
Previous:Comparing Energy ResourcesNext:Circuit Diagrams
Author
Reviewer
Leander Oates

Author: Leander Oates

Expertise: Development Editor

Leander graduated with First-class honours in Science and Education from Sheffield Hallam University. She won the prestigious Lord Robert Winston Solomon Lipson Prize in recognition of her dedication to science and teaching excellence. After teaching and tutoring both science and maths students, Leander now brings this passion for helping young people reach their potential to her work at SME.

Caroline Carroll

Reviewer: Caroline Carroll

Expertise: Head of Content Delivery

Caroline graduated from the University of Nottingham with a degree in Chemistry and Molecular Physics. She spent several years working as an Industrial Chemist in the automotive industry before retraining to teach. Caroline has over 12 years of experience teaching GCSE and A-level chemistry and physics. She is passionate about delivering high-quality resources to help students achieve their full potential.