Climate Change | The Schools' Observatory

The Earth's climate is always changing. It shifts through a regular cycle of temperatures. These cycles last around 100,000 years. They move the Earth through warm periods, then cold ones. This is known as climate oscillation.

Right now, we are in a warm period called an interglacial period. Cold periods are known as ice ages. This natural cycle has happened for millions of years. But it has been changed by humans. This human-led change is called Climate Change.

An infographic illustrating changes in average temperature, displayed in Fahrenheit. The graphic uses color gradients and numerical values to represent temperature shifts over time, indicating warming trends

This work by NASA is licensed under Creative Commons Zero v1.0 Universal

A big effect of climate change is the rise in global temperature. Humans have released greenhouse gases into the atmosphere (read more about the Greenhouse effect below). As greenhouse gases rise, so do the average temperatures on Earth. Not all areas on Earth will experience climate change in the same way.

Some areas will become much warmer. Others will become colder. Higher temperatures cause glaciers to melt. When they melt, more freshwater ends up in the ocean. This contributes to sea-level rise and changes crucial processes in the ocean.

One of these processes is the Gulf Stream. The Gulf Stream brings warm water from the Southern Hemisphere to the UK. If the Gulf Stream becomes weaker, the UK will become colder. Sea-level rise means some coastal areas will disappear underwater. The weather will become more extreme too. This leads to more storms and flooding.

These changes to the environment will have an effect on all life. Some species will become extinct. There are many more impacts of climate change. Climate scientists are working hard to understand them. But there are things we can all do to help tackle climate change.

Some actions are simple, like not wasting energy. We can move to renewable energy sources, like solar and wind power. Wind and solar power reduce the amount of fossil fuels we burn. Fossil fuels like oil and gas release greenhouse gases. We can use energy-saving light bulbs in our homes. We can turn our heating down by a degree. Small changes can help. But we also need countries to work together. To make a big difference, we need global agreements.

An infographic titled 'Ten Indicators of a Warming World,' illustrating the effects of climate change. The diagram includes arrows indicating increasing factors like air temperature near the surface, humidity, sea surface temperature, sea level, ocean heat content, and temperature over land and oceans. Decreasing factors are represented by arrows pointing down, including glaciers, snow cover, and sea ice — Some of the indicators we use to determine the world is heating up

The Greenhouse Effect

The Greenhouse Effect on Earth:

A greenhouse works by allowing the heat from the Sun to go straight in through its glass windows. Once inside, this heat energy is trapped by the glass. This makes the greenhouse get hotter.

You can see this in more detail in the following stages.

Stage 1: Solar Energy

The yellow arrow shows the direction of heat radiation from the Sun. The Suns heat is warming the greenhouse.

An illustration of a house with a blue glass roof and the Sun shining on it. A yellow arrow indicates the direction of heat radiation from the Sun toward the greenhouse, representing the warming effect of solar energy

Stage 2: The Sun's energy enters the Greenhouse

Because the Sun is so hot, the heat radiation can pass through the glass roof of the greenhouse.

A diagram showing the Sun's heat radiation entering the blue glass roof of the house. A yellow arrow passes through the roof, symbolizing the Sun's heat radiation entering the greenhouse

Stage 3: The Sun's energy is absorbed and re-radiated

The inside of the greenhouse absorbs the Sun's radiation and heats up. The greenhouse then produces radiation of its own.

The greenhouse absorbs the Sun's radiation, and orange arrows inside the house show heat being re-radiated from the interior walls and surfaces. The Sun is still shining, but the energy inside the greenhouse is being re-radiated.

Stage 4: The re-radiated energy is trapped

The inside of the greenhouse is much cooler than the surface of the Sun, so it produces a different type of light. This is called infra-red light. It does not pass through the glass as easily. Thus, the heat gets trapped

Orange arrows are trapped inside the greenhouse as the re-radiated energy cannot easily pass through the blue glass roof. The Sun remains in the background, representing how the greenhouse effect traps heat inside

A similar thing can happen to some planets. Instead of glass, some gases in the atmosphere can trap the Sun's heat energy. These gases stop the heat from escaping back into space. These gases are known as Greenhouse Gases. The more of them there are in the atmosphere, the stronger the greenhouse effect is.

There are three main Greenhouse Gases on Earth. They are methane, water vapour, and carbon dioxide (CO2). They occur naturally, but humans can raise their levels.

Methane is produced when plants decompose. It is also produced by rice and cattle farming, and coal mining.
Water vapour is produced when water from oceans and lakes evaporates. It is also produced by burning some fuels.
CO2 is produced when plants and animals respire. It is also produced during forest fires and volcanoes. A lot of CO2 is produced when we burn fossil fuels or make cement. Sometimes humans cut down forests to clear the land for farming. When we do this, we stop those trees from removing CO2 from the atmosphere. This means more CO2 ends up in the atmosphere.

If the amount of greenhouse gases increases, so does the average temperature on Earth. This leads to climate change. One effect of climate change is the melting of polar ice.

An infographic explaining the Greenhouse Effect. It illustrates how solar radiation is absorbed by the Earth's surface and re-emitted as infrared radiation. Some of this radiation is reflected back by the atmosphere and absorbed by greenhouse gases, warming the Earth's surface and lower atmosphere. The diagram shows arrows representing the movement of solar and infrared radiation — The Greenhouse Effect on Earth

The Greenhouse Effect on Venus:

Venus has a much stronger greenhouse effect than Earth. The temperature on Venus is around 400°C higher than on Earth. The greenhouse effect makes the surface of Venus even hotter than the surface of Mercury. Although Mercury is closer to the Sun.

Part of

Climate Change

Environment

Electromagnetic Spectrum

Life and Living things

Atmosphere

The Greenhouse Effect on Earth:

The Greenhouse Effect on Venus:

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