climate change factsheet

What is Climate Change?

What is the difference between weather and climate?
The weather is what we experience day to day – the temperature, precipitation (rain, hail, sleet and snow) and wind – which changes hour by hour. Climate on the other hand is the average weather and the nature of its variations that we experience over time.

What is the greenhouse effect?
The greenhouse effect is a natural process, and has existed for millions of years. It is vital for sustaining life on earth.

The rays from the sun give energy to the earth, warming its’ surface. The earth re-radiates this energy back into space in the form of infra-red radiation. There are certain gases in the earth’s atmosphere – such as water vapour, carbon dioxide and methane – that are called greenhouse gases. This is because they allow the sun’s heat to enter the atmosphere, but slow down the flow of its’ leaving, just like the panes in a greenhouse.

The greenhouse effect keeps the surface of the earth some 33°C warmer than it would otherwise be.

What does this have to do with climate change?
Since the industrial revolution, deforestation and manmade emissions of greenhouse gases (particularly carbon dioxide) through the burning of fossil fuels, has led to an imbalance in the make-up of our atmosphere. Carbon dioxide levels in the atmosphere increased by 30% during the last century.

The build-up of greenhouse gases in the atmosphere has led to the earth’s temperatures warming at an unprecedented rate, also known as global warming. Climate change is a broader term that refers to long-term changes in climate, caused by these increased temperatures.

What are the consequences? What are we seeing already?
If emissions continue to grow at present rates, carbon dioxide concentration in the atmosphere is likely to reach twice pre-industrial levels by 2050.

We are already seeing warmer weather and altered weather patterns. We have experienced rising sea levels, loss of biodiversity, changing seasons, major and accelerating reduction in the world’s glaciers and the Arctic ice sheets and an increase in extreme weather events. This could become the rule rather than the exception.

In the UK, central England temperatures have increased by 1°C since the 1970’s and sea levels around the UK have risen 10cm since 1900. We’ve recently seen more extreme weather such as droughts and flooding, as well as hotter average temperatures.

Around the world, the poorest and most vulnerable will be hit the hardest. Africa has the lowest fossil energy use of any world region, yet the continent is the most vulnerable to climate change

Is it true? How can I be sure?
Climate change can be confusing and intimidating. You might have heard one scientist on the news saying urgent action is needed, while another scientist on a different channel says climate change is a natural phenomenon.

The best way for you to overcome any confusion is to understand the basic science.

There is no scientific uncertainty over the impact an increase in greenhouse gases can have – it can be clearly seen in a simple laboratory experiment – and no evidence or theory exists to prove that the same cannot take place in the atmosphere.

And while it is certainly true that there are scientists who question either the existence of climate change or it’s implications, the vast body of international scientists now accept that man-made climate change is happening, and that the evidence is overwhelming.

What can I do?
There is plenty that can and should be done, by all of us. And urgent steps need to be taken to tackle this collective problem. It is vital to remember three things: first, the situation is not hopeless. Second, there is much we can all do, as individuals and organisations. And third, taking action can be enjoyable and economically beneficial.

Personally, you can consider ways to reduce your impact on the environment. Over 40% of current carbon dioxide emissions are caused by the choices we make as individuals. A case in point is with energy savings – for example, just by replacing all the bulbs in your home with energy saving light bulbs, you could save £25 a year on your electricity bill and 100kg of CO2. A good place to look for more advice on seeing how you can reduce your carbon footprint and save money, is the ACT ON CO2 website.

You can also talk to people.

And you can petition those who are in the position to make changes. Write to your MP. Ask businesses what efforts they are undertaking. Challenge those in power to act.

The Carbon Trust
The Department for Environment, Food and Rural Affairs
The Energy Saving Trust
The Met Office
The Pew Centre on Global Climate Change