Renewable Energy, Climate Change and Environmental Sustainability for SS 1

Renewable energy and climate change

Performance Objectives

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

1. explain the meaning of renewable energy and non-renewable energy;
2. identify the types and sources of renewable energy;
3. discuss the meaning and types of climate;
4. discuss what climate change, global warming and the ozone layer means;
5. discuss the relationship between renewable energy and climate change.

Meaning of Renewable and Non-Renewable Energy

Energy is required to power homes, industries, vehicles and electrical appliances. This energy is obtained from various natural resources, which are classified into two main categories based on their availability and replenishment rate: renewable energy and non-renewable energy.

Renewable Energy

Renewable energy is energy obtained from natural resources that replenish themselves naturally over a short period of time and do not run out.

These resources are constantly restored by natural processes. Because of this continuous replenishment, renewable energy is considered sustainable and inexhaustible. Examples of renewable energy sources include sunlight, wind, flowing water and organic matter.

Non-Renewable Energy

Non-renewable energy is energy obtained from natural resources that exist in limited amounts and are consumed much faster than they can form in nature.

These resources take millions of years to form deep within the Earth from the remains of ancient plants and animals. Once these resources are completely depleted, they cannot be replaced within a human lifespan. The most common examples of non-renewable energy are fossil fuels, which include coal, crude oil and natural gas.

Types and Sources of Renewable Energy

Renewable energy exists in several forms depending on the natural resource from which it is captured. Each type relies on a specific source and requires distinct technologies to convert it into usable electricity or heat.

The primary types and sources of renewable energy are:

1. Solar Energy: This is energy captured from the sun. The sun is the ultimate source of solar energy. Solar photovoltaic (PV) panels are used to convert sunlight directly into electricity, while solar thermal systems use the heat of the sun to warm water or spaces.
2. Wind Energy: This is energy generated from moving air currents. The source of wind energy is the wind, which is created by the uneven heating of the Earth’s atmosphere by the sun. Wind turbines capture the kinetic energy of the wind and convert it into electrical energy.
3. Hydroelectric Energy: This is energy produced from flowing or falling water. The source is water from rivers, streams or waterfalls. Hydroelectric power stations use the force of moving water to turn turbines that drive generators to produce electricity.
4. Biomass Energy: This is energy derived from organic materials. The sources of biomass include wood, agricultural crop residues, animal waste and municipal solid waste. These materials can be burned directly to produce heat or converted into biofuels like biogas and ethanol.
5. Geothermal Energy: This is energy obtained from the heat stored deep within the Earth. The source is the natural heat from the Earth’s core, which warms underground water reservoirs to produce steam. This steam is tapped to drive electricity-generating turbines.

Meaning and Types of Climate

Understanding the environment requires a clear distinction between daily weather conditions and long-term atmospheric patterns.

Meaning of Climate

Climate is the average weather condition of a specific geographic region measured over a long period, typically thirty years or more.

While weather refers to the day-to-day changes in temperature, rainfall, wind and humidity, climate describes the stable, long-term patterns of these atmospheric conditions in a particular area.

Types of Climate

The Earth is divided into different climatic zones based on temperature, latitude and rainfall patterns. The major types of climate include:

1. Tropical Climate: This climate is characterized by high temperatures throughout the year and significant rainfall. It is common in regions near the equator, including Nigeria and other parts of West Africa.
2. Dry or Arid Climate: This climate experiences very low rainfall and high rates of evaporation. Temperatures can be extremely hot during the day and cold at night. This climate is typical of deserts and semi-arid regions, such as the northernmost parts of Nigeria.
3. Temperate Climate: This climate has moderate temperatures with four distinct seasons: spring, summer, autumn and winter. It is found in regions midway between the equator and the poles.
4. Continental Climate: This climate features hot summers and very cold, snowy winters. It is mostly found in the interior parts of large landmasses, away from the moderating influence of oceans.
5. Polar Climate: This climate is characterized by extreme cold throughout the year, with temperatures rarely rising above freezing. It is found in the regions surrounding the North and South Poles.

Climate Change, Global Warming and the Ozone Layer

Human industrial activities, particularly the burning of fossil fuels, have significantly altered the composition of the atmosphere. This has led to critical environmental phenomena that affect the planet.

Climate Change

Climate change is the long-term shift in global or regional temperature and weather patterns, primarily driven by human activities.

While natural factors can cause minor shifts in climate, modern climate change is accelerated by human activities such as deforestation, industrialization and the burning of coal, oil and gas. This results in unpredictable weather, rising sea levels, severe droughts and intense flooding.

Global Warming

Global warming is the gradual increase in the average temperature of the Earth’s atmosphere and oceans, primarily caused by the accumulation of greenhouse gases.

Greenhouse gases, such as carbon dioxide, methane and nitrous oxide, act like a blanket around the Earth. They trap heat from the sun that would otherwise escape back into space. This process is known as the greenhouse effect. The excessive release of these gases from human activities intensifies the greenhouse effect, raising global temperatures.

The Ozone Layer

The ozone layer is a thin region of the upper atmosphere, specifically the stratosphere, that contains a high concentration of ozone gas and absorbs most of the harmful ultraviolet radiation from the sun.

The ozone layer acts as a protective shield for living organisms on Earth. Without it, excessive ultraviolet (UV) radiation would reach the Earth’s surface, causing skin cancers, eye cataracts and damage to marine life and agricultural crops. The ozone layer is damaged by man-made chemicals known as Ozone Depleting Substances (ODS), such as chlorofluorocarbons (CFCs) formerly used in refrigerators and aerosol sprays.

Distinction Between the Concepts

It is important to distinguish among climate change, global warming and the ozone layer to avoid confusion:

1. Global warming refers specifically to the rise in global temperatures due to trapped heat.
2. Climate change is a broader term that includes global warming as well as all other side effects of this warming, such as shifting rainfall patterns, melting glaciers and extreme weather events.
3. The ozone layer is a protective atmospheric shield. Its depletion is a separate environmental issue caused by chemical pollutants, although both ozone depletion and climate change involve human-induced changes to the Earth’s atmosphere.

Relationship Between Renewable Energy and Climate Change

The choice of energy sources directly impacts the global climate. There is a strong relationship between how energy is produced and the rate of climate change.

The key aspects of this relationship include:

1. Reduction of Greenhouse Gas Emissions: Traditional non-renewable energy sources, such as coal and oil, release massive amounts of carbon dioxide ($CO_2$) when burned to generate electricity. In contrast, renewable energy technologies, such as solar PV systems and wind turbines, generate electricity without emitting carbon dioxide or other greenhouse gases during operation.
2. Mitigation of Global Warming: By replacing fossil fuel power plants with solar PV installations and other renewable energy systems, the concentration of greenhouse gases in the atmosphere is reduced. This slows down the greenhouse effect and helps control global warming.
3. Environmental Sustainability: Renewable energy sources do not deplete natural resources or destroy ecosystems in the manner that coal mining or oil drilling does. Using solar and wind energy preserves the environment and protects biodiversity, which helps maintain natural climate regulators like forests and oceans.
4. Climate Resilience: Decentralized renewable energy systems, such as stand-alone solar PV installations, are more resilient to extreme weather events caused by climate change. If a severe storm damages a central power grid, localized solar PV systems can continue to provide electricity to homes, hospitals and communities.

Summary of Key Concepts

The core concepts discussed in this unit are summarized below:

1. Renewable energy comes from infinite natural sources like the sun and wind, while non-renewable energy relies on finite fossil fuels that pollute the environment.
2. Solar, wind, hydro, biomass and geothermal are the primary types of renewable energy.
3. Climate is the long-term average of weather conditions over thirty years or more, categorized into tropical, dry, temperate, continental and polar types.
4. Global warming is the rise in Earth’s temperature due to trapped greenhouse gases; climate change is the broader set of resulting weather shifts; the ozone layer is a protective shield against ultraviolet radiation.
5. Adopting solar PV and other renewable energy technologies reduces carbon emissions, directly mitigating global warming and climate change.

Review Questions

Answer the following questions to test understanding of the topic:

1. Define renewable energy and non-renewable energy, giving two examples of each.
2. Identify four types of renewable energy and state their natural sources.
3. Explain the difference between weather and climate.
4. List and describe three major types of climate.
5. Define global warming and explain how the greenhouse effect causes it.
6. What is the primary function of the ozone layer, and how does it differ from global warming?
7. Analyse three ways in which the installation of solar PV systems helps to combat climate change.