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D3.4 · Describe natural and human influences on climate

Learn to describe natural and human influences on climate through clear examples and targeted practice.

Ontario Grade 10 Science

Earth and Space Science: Climate Change

Natural and human influences on Earth’s long-term patterns

A rainy afternoon does not prove that a place has a wet climate. Climate describes patterns in weather over a long time, while weather describes conditions at a particular time and place. Climate can change when natural processes change how much energy Earth receives, keeps, or moves around. Human activities can also influence climate. In this lesson, you will compare these influences and use a simple model to explain how they work.

What you will learn

Distinguish climate from day-to-day weather.
Describe natural influences that can change climate.
Describe human activities that influence climate.
Explain how the natural greenhouse effect differs from its human-driven enhancement.
Use observations and a simple model to connect an influence with a climate change.

1. From weather to climate

You may already know that weather includes conditions such as temperature, rain, snow, and wind. Weather can change from one day to the next. Climate is the usual pattern of weather in a region over many years. A cold day can happen in a warming climate, just as a hot day can happen in a cool climate. One day is not enough to describe a climate pattern.

Climate includes more than average temperature. It can also include typical precipitation, such as rain and snow, and how these conditions vary across seasons. A climate influence is something that can affect these long-term patterns. To describe an influence, connect it to what changes: the energy reaching Earth, the energy retained by the atmosphere, or the movement of heat and water.

Weather describes short-term conditions; climate describes long-term patterns.
A single event does not establish a climate trend.
Climate influences can affect temperature and other weather patterns.

2. Natural influences on climate

Natural influences occur without human activity. They can affect climate for different lengths of time and in different ways. The Sun supplies most of the energy that warms Earth. If the amount of solar energy reaching Earth changes, this can influence climate. Natural changes in the Sun’s output are one possible influence.

Large volcanic eruptions can send ash and tiny particles into the atmosphere. These particles can reflect some incoming sunlight back toward space. For a time, less solar energy may reach the surface, which can contribute to cooling. The effect depends on the eruption and how long particles remain in the atmosphere. Volcanic activity does not produce the same climate effect in every case.

The ocean and atmosphere move heat from place to place. Ocean currents are large movements of ocean water. They can carry heat toward or away from a region and influence its climate. A change in these movements can shift regional patterns without changing the Sun’s energy reaching Earth.

A surface’s reflectiveness also matters. Albedo means how much sunlight a surface reflects. Snow and ice reflect a lot of sunlight. Darker surfaces, such as open water, reflect less and absorb more. If the area covered by snow or ice changes, the balance between reflected and absorbed sunlight can change. This is one way natural changes in Earth’s surface can influence climate.

These examples show why climate can vary naturally. They do not mean that every observed climate change has the same cause. The influence must be considered alongside evidence about what changed and when.

Natural influences include changes in solar energy, volcanic particles, ocean heat movement, and surface reflectiveness.
Reflecting sunlight tends to reduce the energy absorbed at the surface.
Natural influences can affect a region or contribute to broader climate changes.

3. Human influences and the greenhouse effect

The atmosphere contains greenhouse gases. These gases absorb and re-emit some energy leaving Earth’s surface, which helps keep the planet warm enough for life. This natural greenhouse effect is not pollution by itself. It is a normal part of Earth’s climate system.

Human activities can increase the amount of some greenhouse gases in the atmosphere. For example, burning coal, oil, or natural gas for energy releases carbon dioxide. Cutting forests can also affect the amount of carbon dioxide in the atmosphere because trees take in carbon dioxide as they grow, and stored carbon can be released when trees are burned or decay. Some farming and waste activities release other greenhouse gases.

When greenhouse gases increase, the atmosphere absorbs and re-emits more of the energy leaving Earth’s surface. This strengthens the natural greenhouse effect. It is called the enhanced greenhouse effect. It adds to the natural effect; it does not mean the natural greenhouse effect has suddenly begun. The result is a warming influence on climate.

People can also affect climate by changing land surfaces. For example, replacing a forest with buildings changes the surface and can change how sunlight is reflected or absorbed. The effects of land changes depend on the place and what replaces the original surface. Human influences can therefore include both greenhouse-gas increases and changes to land.

The natural greenhouse effect warms Earth and is part of the climate system.
Human activities can increase greenhouse gases and enhance this natural effect.
Human land changes can also alter how a surface reflects or absorbs sunlight.

4. Using evidence and a model

A model is a simplified way to show how parts of a system are connected. A useful climate model for this lesson is a chain of cause and effect: an influence changes incoming sunlight, absorbed energy, heat movement, or energy retained by the atmosphere; this can then affect climate patterns. The model helps organize an explanation, but it is not a complete picture of every process.

Evidence can include long-term records of temperature, precipitation, or other climate conditions, along with observations of possible influences. A record over many years is more useful for identifying a climate pattern than a single weather report. A careful explanation states what the evidence shows and avoids claiming that one observation proves a cause.

When comparing explanations, ask: Is the proposed influence natural or human? What part of the climate system could it affect? Does the timing fit the observed pattern? More than one influence can operate at once. For example, natural variation can occur while human greenhouse-gas emissions add a warming influence.

Climate records and models do not require students to create heat-trapping gases. For classroom learning, use published observations or clearly labelled hypothetical data. Do not mix chemicals or burn fuels to test the greenhouse effect at home. Such activities can be unsafe and would not reproduce Earth’s climate system.

Use long-term patterns rather than one day’s weather to discuss climate.
A good explanation connects a named influence to a possible climate effect.
Natural and human influences can operate at the same time.
Use safe observations or hypothetical data; do not attempt chemical or combustion experiments at home.

Examples of climate influences

Influence	Type	Possible connection to climate
Changes in solar energy	Natural	Can change the energy reaching Earth
Particles from a large volcanic eruption	Natural	Can reflect sunlight and reduce energy reaching the surface
Ocean currents	Natural	Can move heat toward or away from a region
Burning fossil fuels	Human	Releases carbon dioxide and can enhance the greenhouse effect
Changing forests to other land uses	Human	Can affect carbon dioxide and surface reflection or absorption

Worked example

A volcanic influence

A class reads that a large eruption released particles into the atmosphere. Explain one possible short-term climate influence without claiming that the eruption caused every later temperature change.

Identify the influence
The eruption is a natural influence. The particles it releases can affect how much sunlight reaches Earth’s surface.
Connect cause and effect
If the particles reflect some incoming sunlight back toward space, less energy may be absorbed at the surface. This can contribute to temporary cooling.
Keep the claim limited
The conclusion is a possible influence, not proof that the eruption explains every later climate pattern. Other influences may also be acting.

Answer: Atmospheric particles from a large eruption can reflect some sunlight, reducing energy absorbed at Earth’s surface and contributing to temporary cooling.

Check: The explanation names a natural cause, describes a plausible link, and avoids treating one influence as the only cause.

Worked example

A human influence

A hypothetical community report says that fuel use increased over several years. Describe a possible climate influence and distinguish it from the natural greenhouse effect.

Name the human activity
The report describes increased fuel use. Burning fuels such as coal, oil, or natural gas releases carbon dioxide.
Apply the greenhouse model
More carbon dioxide can strengthen the atmosphere’s absorption and re-emission of energy leaving Earth’s surface. This adds to the natural greenhouse effect.
State the climate influence
The strengthened greenhouse effect is a human-driven warming influence. The natural greenhouse effect already exists; the human influence enhances it.

Answer: Increased fuel burning can release more carbon dioxide, enhancing the natural greenhouse effect and adding a warming influence on climate.

Check: The example is explicitly hypothetical and does not treat the natural greenhouse effect as human-caused.

Worked example

Reading a hypothetical climate record

A hypothetical regional record shows that average temperatures rose across several decades. During part of that time, ocean currents also changed. Explain why the record alone does not identify one cause, and name one natural and one human influence that could be considered.

Describe the evidence
The record shows a long-term rise in average temperature. Because it covers decades, it describes a climate pattern rather than one day’s weather.
Consider natural influence
Changed ocean currents could move heat differently and affect the region’s climate. This is a natural influence to consider.
Consider human influence
Increased greenhouse gases from human activities could enhance heat retention in the atmosphere. The temperature record by itself does not show how much each influence contributed.

Answer: The hypothetical record indicates a long-term warming pattern, but it does not by itself identify the cause. Changed ocean heat movement is a natural influence to consider; increased human greenhouse-gas emissions are a human influence to consider.

Check: The answer separates the observed pattern from possible causes and includes one influence of each type.

Common mistakes and how to avoid them

Using one cold day as proof that the climate is not warming.

Correction: A day is weather. Climate is described using patterns over many years.

Saying that the greenhouse effect is entirely caused by people.

Correction: The natural greenhouse effect exists without human activity. Human activities can enhance it by increasing greenhouse gases.

Assuming that every natural influence causes cooling.

Correction: Natural influences can have different effects. For example, volcanic particles may reduce incoming sunlight, while ocean currents can move heat into or away from a region.

Naming a possible cause as if one observation proves it.

Correction: Separate the observed climate pattern from possible influences. Consider the evidence and allow for more than one influence.

Lesson summary

Weather is short-term; climate is the long-term pattern of weather in a region.
Natural influences include changes in solar energy, volcanic particles, ocean heat movement, and surface reflectiveness.
Human influences include greenhouse-gas emissions and changes to land surfaces.
The natural greenhouse effect warms Earth. Human activities can enhance it by increasing greenhouse gases.
Use long-term observations and careful cause-and-effect reasoning. Natural and human influences can occur together.

Check your understanding

Question 1

Which statement best distinguishes climate from weather?

Climate is a long-term pattern; weather describes conditions at a particular time and place.
Climate is the temperature at noon; weather is the yearly average.
Climate describes only rain; weather describes only temperature.
Climate never changes, but weather changes every day.

Show answer and explanation

Climate is a long-term pattern; weather describes conditions at a particular time and place.

Climate describes patterns over many years. Weather describes conditions over a shorter time.

Question 2

How can particles from a large volcanic eruption influence climate?

They can reflect some sunlight, so less energy may reach the surface for a time.
They always make the atmosphere warmer by adding greenhouse gases.
They stop ocean currents from moving heat.
They prove that human activities have no climate influence.

Show answer and explanation

They can reflect some sunlight, so less energy may reach the surface for a time.

Particles from a large eruption can reflect sunlight. This can reduce energy reaching the surface and contribute to temporary cooling.

Question 3

What does it mean when human activities enhance the greenhouse effect?

Human activities increase greenhouse gases, strengthening a natural effect that already exists.
People create the natural greenhouse effect from nothing.
Greenhouse gases prevent any energy from reaching Earth.
The atmosphere no longer affects energy leaving Earth.

Show answer and explanation

Human activities increase greenhouse gases, strengthening a natural effect that already exists.

The natural greenhouse effect is part of Earth’s climate system. Added greenhouse gases from human activities can strengthen it.

Key terms

Climate: The usual pattern of weather in a region over many years.
Weather: Conditions such as temperature, precipitation, and wind at a particular time and place.
Climate influence: A natural process or human activity that can affect long-term climate patterns.
Greenhouse gas: A gas in the atmosphere that absorbs and re-emits some energy leaving Earth’s surface.
Natural greenhouse effect: The warming effect caused by greenhouse gases that occur naturally in the atmosphere.
Enhanced greenhouse effect: The strengthening of the natural greenhouse effect when human activities increase greenhouse gases.
Albedo: How much sunlight a surface reflects.
Ocean current: A large movement of ocean water that can carry heat from one place to another.

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Published by DoAssignment. This reviewed lesson follows Ontario Grade 10 Science (SNC2D), expectation D3.4. It is a study resource, not an official curriculum publication.

Before publication, content is checked for structure, mathematical or chemical notation, calculations, course boundaries, and readability. Errors can still occur, so corrections are welcomed.

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