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Understand Climate Change

Read on for our Beginner’s Guide to Climate Change.

Understanding Climate Change

If you’ve landed on this page, you might be wondering “What is climate change and why is it happening?“. Before we can answer those questions we’re going to go back to basics for a little geography lesson, to help you understand the greenhouse effect. This is a process which makes the Earth warmer, and therefore, a more comfortable place to live.

What is the Greenhouse Effect?

The Sun radiates energy towards the Earth. Whilst some of this energy is reflected back into space, some is absorbed by the Earth’s surface. This absorbed energy is then converted into heat and is re-radiated back out into the atmosphere.

In the Earth’s atmosphere there are gases that have the ability to trap the heat that would otherwise escape, called greenhouse gases (GHGs). This is the greenhouse effect; which heats up the Earth’s surface and the lower atmosphere. At the right levels, these gases ensure that the atmosphere holds onto enough heat to support life. Without any of these gases, the temperature on Earth would be about 30°C lower than it is today.

Therefore, the level of GHGs in our atmosphere are directly linked to the temperatures we experience here on Earth.

Greenhouse Effect

The Greenhouse Effect

Important Definitions!


Weather is what is happening to the atmosphere at any given time; the day-to-day state of the atmosphere. Weather refers to short-term changes in the atmosphere.


Climate is a measure of what the weather is like over a long period of time in a specific area. This measure is based on observations and statistics over many years.

Global Warming

Global warming is the long term trend of rising or increasing average global temperatures.

Climate Change

Changes in the global climate, resulting from the increasing average global temperature; e.g. changes in precipitation patterns, increased prevalence of droughts, heat waves, and other extreme weather.

Types of Greenhouse Gases

There are many different types of greenhouse gases. The effect that each has on climate change depends on 3 main factors; the amount of the gas in the atmosphere (which is usually measured in parts per million or ‘ppm’), how long the gas stays in the atmosphere, and how effective the gas is in terms of trapping heat to make the Earth warmer.

Global Warming Potential (GWP) is a measure of how much energy the emissions of 1 ton of a greenhouse gas will absorb over a given period of time (usually a hundred years). The GWP is relative to the emissions of 1 ton of the reference gas which is carbon dioxide, which is assigned a value of 1. So essentially, a small amount of a gas with a high GWP can have a large impact on increasing warming!

Water Vapour

Water Vapour

Carbon Dioxide

Carbon Dioxide



Nitrous Oxide

Nitrous Oxide

F Gases


So, what’s the problem?

If the greenhouse effect and GHGs help make our planet habitable, then what’s the problem?

Scientists and researchers have discovered that our climate naturally fluctuates between hot and cold periods over many hundreds and thousands of years.

Ancient air bubbles trapped in ice help us to see what Earth’s atmosphere and climate were like in the past. Ice cores tell us that levels of carbon dioxide or CO2 (a GHG, which we know is directly linked to temperature) in the atmosphere are higher than they have been at any time in the past 400,000 years. During ice ages, CO2 levels were around 200 ppm, and during the warmer periods they hovered around 280 ppm.

In 2013, CO2 levels surpassed 400 ppm for the first time in recorded history; you can see when this happens as the line on the graph shoots directly upwards! This is just one of the ways in which we can tell that climate change like never before is really happening.

Today, we stand on the threshold of a new geologic era, which some term the “Anthropocene“. This is a time where the climate is very different to the one our ancestors knew, and it comes down to the activities of human beings like us.

NASA Vostok Ice Core Data

Vostok Ice Core CO2 Data from NASA: Global Climate Change Vital Signs of the Planet

Human Induced Climate Change

The graph above not only shows the scientific measurements, but it also underscores the fact that humans have a great capacity to change the climate and thereafter, the planet. The problems truly begin when GHG levels get too high, because of our activities.

Since the Industrial Revolution in the 18th Century, the concentration of GHGs in the atmosphere has been increasing significantly, mainly due to the burning of fossil fuels. Higher concentration’s of GHGs in the atmosphere means that less heat is able to escape into space and is instead being trapped in our atmosphere by these gases, heating up the Earth’s surface and its lower atmosphere more and more. This results in a long term trend of increasing average global temperature, or in other words, global warming.

Even small changes in the average global temperature can cause major and dangerous shifts in climate and weather such as; changes in precipitation patterns, increased prevalence of droughts, heat waves, and other extreme weather. These changes are referred to as climate change.

Since the pre-industrial period, human activities are estimated to have increased Earth’s global average temperature by about 1°C, and if that doesn’t seem like much to you, just consider the difference between 0 and 1°C… that 1°C means the difference between ice and water.

fossil fuels being burned for energy

“Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. It is extremely likely that human influence has been the dominant cause of this warming since the mid-20th century.”

The Intergovernmental Panel on Climate Change (IPCC), 2014

Further Reading

Want to learn some more? Check out these useful links for more information on what climate change is, why it is happening and how we know it is occurring.

Now that you know the basics, it’s time to learn more about…

The Impacts of Climate Change!

Get in Touch

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If you would like to know more about what we are doing please get in touch. We are always looking for new members to join our organisation. If you have particular knowledge around climate change issues, or growing, making and mending skills you’d like to share, or just want to know more, we want to hear from you. Everyone is welcome, together we can make a difference.