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Responding to change (a2 only)
Infection and response
Homeostasis and response
Energy transfers (a2 only)
Cell biology
Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
Organisation
Substance exchange
Bioenergetics
Genetic information & variation
Inheritance, variation and evolution
Genetics & ecosystems (a2 only)
Ecology
Cells
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1l the quest for political stability: germany, 1871-1991
Britain & the wider world: 1745 -1901
The cold war
Inter-war germany
Medieval period: 1066 -1509
2d religious conflict and the church in england, c1529-c1570
2o democracy and nazism: germany, 1918-1945
1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
2m wars and welfare: britain in transition, 1906-1957
World war two & the holocaust
2n revolution and dictatorship: russia, 1917-1953
2s the making of modern britain, 1951-2007
World war one
Britain: 1509 -1745
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13
1
Hannah
28/11/2025
Geography
Hazardous Earth Whole Topic Notes - GCSE Edexcel B Geography
691
•
28 Nov 2025
•
Hannah
@hannnah_study
Ever wondered why weather patterns exist and why Earth's climate... Show more




Think of Earth's atmosphere like a giant conveyor belt system that moves air around the planet. Winds form because air naturally flows from high pressure areas to low pressure areas, creating predictable patterns that drive our weather.
The atmosphere works through three circulation cells in each hemisphere: Hadley, Ferrel, and Polar cells. Here's how it works: the Sun heats air at the equator, making it rise and create low pressure. This warm air cools as it moves away from the equator, then sinks at 30° north and south, forming high pressure belts where you'll find many of the world's deserts.
Trade winds blow from these 30° zones back toward the equator, whilst westerlies blow from 30° toward the poles. Understanding this system helps explain why certain regions have consistent weather patterns and why storms move in predictable directions.
Climate has always changed naturally. During the Quaternary period (the last 2.6 million years), Earth cycled between cold glacial periods lasting 100,000 years and warmer interglacial periods lasting 8,000-12,000 years. However, in just the last 200 years, temperatures have risen 0.8°C - that's incredibly fast in geological terms.
Key Point: The greenhouse effect occurs when greenhouse gases absorb long-wave radiation reflected from Earth's surface and re-radiate it back, trapping heat in our atmosphere.

Scientists use clever methods to understand past climates. Ice cores act like frozen history books - each annual layer of ice contains gases that reveal ancient temperatures and atmospheric conditions stretching back thousands of years. Tree rings work similarly; thick rings indicate warm, wet growing seasons whilst thin rings show harsh conditions.
The UK has experienced dramatic climate shifts throughout history. During the Medieval Warm Period , temperatures were 1-2°C warmer than in 2000, likely due to increased solar radiation. Conversely, the Little Ice Age brought temperatures 1°C cooler, causing harsh winters and cool summers that affected agriculture and daily life.
Natural climate change happens through several mechanisms. Volcanic eruptions blast particles into the atmosphere that reflect sunlight away from Earth, cooling temperatures whilst also releasing CO₂. Earth's orbit changes from circular to elliptical over 96,000-year cycles, affecting how much solar radiation we receive.
Human factors now dominate climate change. Fossil fuels release massive amounts of greenhouse gases when burned for energy and transport. Deforestation removes trees that naturally absorb CO₂. Even agriculture contributes - cows produce methane through digestion, and rice paddies emit methane as organic matter decomposes underwater.
Key Point: Human activities now release greenhouse gases much faster than natural processes can absorb them, causing rapid warming.

Climate change is already transforming our planet in measurable ways. Arctic sea ice shrinks by 13% per decade, and global sea levels rose 16-21 cm between 1900 and 2016. These aren't distant future problems - they're happening now.
Environmental impacts include more frequent heatwaves and extreme weather events since 1950. Rising sea surface temperatures cause coral bleaching and fuel stronger, more frequent cyclones. Species distributions are shifting as animals and plants struggle to adapt to rapidly changing conditions, with those unable to evolve quickly enough facing extinction.
Social impacts affect human communities directly. Coastal flooding from sea level rise forces people to migrate, potentially creating overcrowded areas and resource conflicts. Changing precipitation patterns and higher temperatures reduce crop yields in many regions, threatening food security.
Water availability becomes critical as hotter temperatures increase drought frequency. This could spark conflicts between nations competing for clean water resources. More heat-related deaths occur during extreme weather events, which also cause significant financial damage to communities.
The speed of current climate change is the real problem. Whilst species and ecosystems can adapt to gradual changes over thousands of years, the rapid pace of human-caused warming leaves little time for natural adaptation.
Key Point: Climate change impacts are interconnected - environmental changes directly affect human society through food, water, and housing security.
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Hannah
@hannnah_study
Ever wondered why weather patterns exist and why Earth's climate is changing so rapidly? Global atmospheric circulation creates the winds and weather systems that shape our planet's climate, but human activities are now dramatically altering these natural patterns in ways... Show more

Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Think of Earth's atmosphere like a giant conveyor belt system that moves air around the planet. Winds form because air naturally flows from high pressure areas to low pressure areas, creating predictable patterns that drive our weather.
The atmosphere works through three circulation cells in each hemisphere: Hadley, Ferrel, and Polar cells. Here's how it works: the Sun heats air at the equator, making it rise and create low pressure. This warm air cools as it moves away from the equator, then sinks at 30° north and south, forming high pressure belts where you'll find many of the world's deserts.
Trade winds blow from these 30° zones back toward the equator, whilst westerlies blow from 30° toward the poles. Understanding this system helps explain why certain regions have consistent weather patterns and why storms move in predictable directions.
Climate has always changed naturally. During the Quaternary period (the last 2.6 million years), Earth cycled between cold glacial periods lasting 100,000 years and warmer interglacial periods lasting 8,000-12,000 years. However, in just the last 200 years, temperatures have risen 0.8°C - that's incredibly fast in geological terms.
Key Point: The greenhouse effect occurs when greenhouse gases absorb long-wave radiation reflected from Earth's surface and re-radiate it back, trapping heat in our atmosphere.

Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Scientists use clever methods to understand past climates. Ice cores act like frozen history books - each annual layer of ice contains gases that reveal ancient temperatures and atmospheric conditions stretching back thousands of years. Tree rings work similarly; thick rings indicate warm, wet growing seasons whilst thin rings show harsh conditions.
The UK has experienced dramatic climate shifts throughout history. During the Medieval Warm Period , temperatures were 1-2°C warmer than in 2000, likely due to increased solar radiation. Conversely, the Little Ice Age brought temperatures 1°C cooler, causing harsh winters and cool summers that affected agriculture and daily life.
Natural climate change happens through several mechanisms. Volcanic eruptions blast particles into the atmosphere that reflect sunlight away from Earth, cooling temperatures whilst also releasing CO₂. Earth's orbit changes from circular to elliptical over 96,000-year cycles, affecting how much solar radiation we receive.
Human factors now dominate climate change. Fossil fuels release massive amounts of greenhouse gases when burned for energy and transport. Deforestation removes trees that naturally absorb CO₂. Even agriculture contributes - cows produce methane through digestion, and rice paddies emit methane as organic matter decomposes underwater.
Key Point: Human activities now release greenhouse gases much faster than natural processes can absorb them, causing rapid warming.

Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Climate change is already transforming our planet in measurable ways. Arctic sea ice shrinks by 13% per decade, and global sea levels rose 16-21 cm between 1900 and 2016. These aren't distant future problems - they're happening now.
Environmental impacts include more frequent heatwaves and extreme weather events since 1950. Rising sea surface temperatures cause coral bleaching and fuel stronger, more frequent cyclones. Species distributions are shifting as animals and plants struggle to adapt to rapidly changing conditions, with those unable to evolve quickly enough facing extinction.
Social impacts affect human communities directly. Coastal flooding from sea level rise forces people to migrate, potentially creating overcrowded areas and resource conflicts. Changing precipitation patterns and higher temperatures reduce crop yields in many regions, threatening food security.
Water availability becomes critical as hotter temperatures increase drought frequency. This could spark conflicts between nations competing for clean water resources. More heat-related deaths occur during extreme weather events, which also cause significant financial damage to communities.
The speed of current climate change is the real problem. Whilst species and ecosystems can adapt to gradual changes over thousands of years, the rapid pace of human-caused warming leaves little time for natural adaptation.
Key Point: Climate change impacts are interconnected - environmental changes directly affect human society through food, water, and housing security.
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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Explore key concepts in GCSE Geography related to natural hazards, including the dynamics of tectonic plates, the formation of tropical storms, and the impact of climate change. This summary covers essential topics such as the Saffir-Simpson scale, greenhouse gases, and the effects of hurricanes like Irma and Matthew. Ideal for exam preparation and understanding the challenges posed by natural disasters.
Explore effective strategies for mitigating climate change, including afforestation, international agreements like the Kyoto Protocol and Paris Agreement, and alternative energy solutions. This summary covers the greenhouse effect, human and natural factors contributing to global warming, and adaptation strategies to combat climate impacts. Ideal for Geography GCSE (AQA) students.
Explore the causes, evidence, and consequences of climate change in this informative poster. Learn about greenhouse gases, global warming, and practical steps to mitigate climate change effects. Ideal for Year 8 students, this resource highlights the importance of energy conservation and sustainable practices.
App Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user