What are the Threats to Life on Earth?

Content Standards

In this lesson, students will understand the significant threats to life on Earth, including climate change, biodiversity loss, and pollution, collectively known as the triple planetary crisis.

Performance Standards

Students will be able to:

Identify the key threats to Earth’s balance.
Explain the causes and effects of climate change, biodiversity loss, and pollution.
Describe global efforts and personal actions to protect life on Earth.

Alignment Standards

Reference: NCERT Book Alignment

The lesson is aligned with the NCERT Grade 8 Science Textbook, Chapter 13: Our Home: Earth, a Unique Life Sustaining Planet, Section 13.6 : What Are the Threats to Life on Earth?

Learning Objectives

By the end of the lesson, students will be able to:

Define and explain climate change, biodiversity loss, and pollution.
Analyze how human activities disturb Earth’s balance.
Recognize the impact of global warming on ecosystems and human life.
Suggest sustainable practices to reduce threats to the environment.

Prerequisites (Prior Knowledge)

Basic understanding of ecosystems and the interdependence of plants and animals.
Awareness of daily environmental issues (e.g., pollution, waste, deforestation).

Introduction

In this session, students will explore the triple planetary crisis that threatens life on Earth. They will connect real-life events like smog, floods, and glacier melting to scientific concepts such as greenhouse gases, biodiversity, and pollution.

Timeline (40 Minutes)

Title	Approximate Duration	Procedure	Reference Material
Engage	5	Ask: “What happens if Earth becomes just 1°C hotter?” Show a short clip or image of melting glaciers.	Slides
Explore	10	Discuss: “How does air pollution affect your health?” and “What happens to fish when plastic enters water?” Students share real-life observations.	Slides
Explain	10	Explain major threats Climate change → rising temperatures, melting ice Biodiversity loss → habitat destruction, species decline Pollution → air, water, soil contamination. Virtual Lab: Students visualise CO₂ rise, glacier melt, and pollution spread.	Slides and Virtual Lab
Evaluate	10	Students will attempt the Self Evaluation task on LMS.	Virtual Lab
Extend	5	Think–Pair–Share: “What actions can YOU take daily to help Earth?” Students propose solutions.	Slides

What are the Threats to Life on Earth?

Introduction

In this session, you will explore how human activities, such as burning fuels and pollution, disrupt the delicate balance between living and non-living components of the Earth’s ecosystem.

Theory

Introduction:

Life on Earth depends on a delicate balance between living things (plants, animals, humans) and non-living systems (air, water, soil). Human activities are disturbing this balance, creating serious threats such as climate change, biodiversity loss, and pollution, also called the triple planetary crisis. Understanding these threats helps us realise the importance of protecting our environment for the future.

The Main Threats

1. Climate Change
Burning fossil fuels like coal, petrol, and natural gas releases greenhouse gases (carbon dioxide, methane). These trap heat, causing global warming.

Effects: melting glaciers, rising sea levels, stronger storms, floods, and extinction of species.
Example: Coastal cities may flood if sea levels continue to rise.

2. Biodiversity Loss
When forests are cut or habitats are destroyed, plants and animals disappear. This breaks the food chain.

Example: If grasses vanish, herbivores like deer suffer, which in turn affects predators like tigers.
Every species plays a role, and losing even one weakens ecosystems.

3. Pollution

Pollution harms air, water, and soil.

Air pollution: From factories and vehicles → causes breathing problems, smog, acid rain.
Water pollution: From plastic waste and chemicals → kills fish, makes water unsafe.
Soil pollution: From excess fertilizers and waste → reduces crop yield, contaminates food.

Global Efforts

Countries have made agreements to protect the environment:

Montreal Protocol (1987): Reduced CFCs, helped ozone layer recover.
Earth Summit (1992): Focus on climate and biodiversity.
Kyoto Protocol (2005) & Paris Agreement (2015): Reduce greenhouse gases, limit warming to 1.5 °C.

What Can We Do?

Use renewable energy like wind and solar.
Reuse, recycle, and repair items.
Save water and energy at home.
Encourage others to act responsibly for the environment.

Vocabulary

This is the list of vocabulary terms used throughout the lesson.

Climate Change: Long-term changes in temperature, rainfall, and weather patterns caused by human activities.
Greenhouse Gases: Gases like carbon dioxide and methane that trap heat in the Earth’s atmosphere.
Biodiversity: Variety of plants, animals, and microorganisms in a given area.
Pollution: Presence of harmful substances in air, water, or soil.
Global Warming: Increase in Earth’s average temperature due to trapped greenhouse gases.
Ozone Layer: A layer in Earth’s atmosphere that protects us from harmful UV rays.
Renewable Energy: Energy from natural sources that do not run out, like solar and wind.
Ecosystem: A community of living things interacting with their physical environment.
Food Chain: Sequence of organisms where energy is passed from plants to herbivores to predators.

Sustainable Practices: Actions that use resources wisely to protect them for the future.

What are the Threats to Life on Earth?

Introduction

In this VR activity, students will see how human actions like burning fuels and pollution disturb Earth’s balance, causing climate change, melting glaciers, and loss of biodiversity. They will also explore how trees absorb carbon dioxide to keep nature in balance.

Key Features

Animated simulation of Earth’s ecological balance.
Visual scenes of trees absorbing CO₂, glaciers melting, and pollution spreading.
Demonstration of human impact: fossil fuel burning, deforestation, and waste dumping.
Clear contrast between balanced nature and disturbed ecosystems.
Real-world links: climate change, biodiversity loss, and pollution.
Embedded short quiz (2 MCQs) for quick reinforcement.

Step-by-Step Procedure for VR Experience

Step 1: Enter the Virtual Lab
Students begin inside a virtual Earth environment showing natural landscapes.
Step 2: Observe Climate Change
Watch animations of burning fossil fuels releasing smoke, leading to rising temperatures and melting glaciers.
Step 3: See Air Pollution
Experience a city filled with smog and factory smoke, showing how pollution affects breathing and crops.
Step 4: Understand Biodiversity Loss
See forests being cut down, animals disappearing, and the food chain breaking.
Step 5: Discover Nature’s Role
Watch how trees absorb CO₂ and keep balance in the atmosphere.
Step 6: Explore Global Agreements
Visuals highlight international efforts like the Paris Agreement to fight climate change.
Step 7: Learn Solutions
Interactive scenes show renewable energy like windmills and solar panels, along with recycling practices.
Step 8: Reflection
Students complete a short quiz on the threats and solutions, reinforcing what they learned.