Climate change: causes and effects explained

Climate change is the long-term change in average weather patterns and average temperatures across the world. The main cause of climate change is greenhouse gas emissions such as carbon dioxide, which trap in the sun’s heat.

Without climate change, we’d still experience different seasons and weather conditions. Climate change is different. It refers to the way those weather patterns are changing over a much longer period of time. 

The climate emergency refers to a situation in which urgent action is needed to reduce or stop climate change and avoid potentially irreversible environmental damage. Climate change can happen naturally over long periods of time, but rapid climate change caused by human activity since the 1800s has created the emergency. 

It’s important that we address the climate emergency because it has impacts on people and the planet. For example, climate change causes droughts, which can cause crop failure.

This has a very real impact on people around the world, especially those in low-income places like southern Africa, which experienced droughts early last year. This is a type of climate injustice because on average, these countries have contributed the least to climate change.

While climate change and global warming are connected, they’re not the same thing. Global warming refers to a gradual rise in global average temperatures. This leads to climate change.

In 2015, the international community recognised the need to limit global warming. A target was set to stop global average temperatures rising by more than 2°C above pre-industrial levels. Nations around the world were also tasked with taking action to limit this rise to 1.5°C before 2050 as part of the Paris Agreement. However, across 2024 the rise in average global temperatures passed 1.5°C for the first time. 

While an increase of 2°C might not sound like much, it can drastically alter our weather patterns and increase the risk of species going extinct. Staying below these limits will help us to avoid the worst effects of climate change. 

Climate change is caused by the release of greenhouse gasses such as carbon dioxide (CO2) into the atmosphere.

• Human activity such as agriculture or burning oil and coal causes CO2 and methane to be released into the atmosphere. 
• These gasses act like a blanket, keeping in heat. 
• As the sun shines, the heat gets trapped in the atmosphere, which causes the Earth’s temperature to rise. 
• This is called the greenhouse effect because it works in a similar way to a greenhouse you might find in a garden. 

Every day human activities such as heating buildings and transport release greenhouse gasses and therefore contribute to climate change. 

Climate change is also caused by deforestation and the destruction of natural habitats. This can be driven by agriculture and the food we eat.

Rising global temperatures cause weather patterns to change. This means that extreme weather events such as flooding, heat waves, droughts and hurricanes become more frequent and more severe. This can have several effects: 

 Environmental impacts: 

• crop failure 
• reduced biodiversity 
• spread of diseases 
• limited access to fresh water 

Societal impacts: 

• reduced food and water security 
• health risks 
• risk of conflict 
• population displacement 
• growing inequality 
• destruction of homes 

You might have heard the term ‘net zero’ before. This means achieving a balance between the carbon emitted into the atmosphere, and the carbon removed from it. This balance will happen when the carbon we add to the atmosphere is no more than the amount that gets taken out.

To achieve net zero, everyone needs to reduce their carbon footprint while also finding ways to remove the emissions that are in the atmosphere already. This can be done by changing how we use our land so it can absorb more carbon dioxide. 

At Energy Saving Trust, we believe in building a net zero future that benefits everyone. We’re helping the UK reach net zero by offering expert, impartial energy saving advice to people, businesses and governments.

We help millions of people every year to make better energy choices. We also support businesses with energy efficiency strategies, research and communications, enabling them to play their part in building a sustainable future.

Our policy manger Elaine Waterson says: 

“We champion policies that support energy efficiency and the transition to clean heating – key to achieving a net zero future.

“We regularly engage with governments across the UK and collaborate with a wide range of stakeholders. This helps shape policies that make it easier for people to upgrade to clean heating and improve the energy efficiency of their homes and buildings.

“Our policy work is grounded in real-world insight from households and businesses and informed by our cross-UK and international experience.” 

Sign up to our monthly newsletter Energywire to stay up to date with the latest energy advice and news.