Easy guide to climate change
The science in a nutshell
The Earth gets its heat straight from the Sun, but some of it gets reflected back out into space. Fortunately, certain gases in the atmosphere act like a greenhouse, keeping the heat in. Without this greenhouse effect, the average temperature on earth would be a chilly -20 °C (-4 °F)!
The gases which are most important in the greenhouse effect are carbon dioxide (also know as CO2) and methane. These gases are naturally present, but we add more to the atmosphere by the way we live. A lot of the CO2 we produce is through burning coal, oil and gas for energy and transport, whereas methane is produced through intensive farming, or the decomposition of rubbish in landfill sites.
As we produce more CO2 and methane, we make the greenhouse effect stronger. This means that more heat is kept in by the atmosphere.
What is climate change?
Throughout history, the Earth's climate has changed due to natural causes. However, recently, scientists have identified more extreme changes in the world's climate which they believe are caused by the activities of humans. When people talk about climate change, they're often talking about these human effects.
In Europe, climate change is leading to warmer temperatures, wetter winters, drier summers, less snow, higher sea levels and flooding of coastal areas.
Throughout the world, people most vulnerable to changes in the weather may face serious problems. Flooding, drought, food shortages and the spread of diseases are set to cause problems on a global scale.
How are we changing the climate?
The impact that we have on the climate is mainly through burning fossil fuels such as coal, oil and gas for energy, which produces carbon dioxide (also known as CO2) and changes the makeup of the atmosphere.
This is bad news because if it happens too quickly, people and wildlife can't adapt easily to the changes in temperature, rainfall and sea level.
The link between CO2 and warming
Since 1957, levels of CO2 in the atmosphere have been monitored at Mauna Loa in Hawaii. This location was chosen because of its remote position away from major emissions sources. The graph shows a clear increase in levels of CO2, up to about 380ppm (parts per million) today. Until the Industrial Revolution in the 18th Century, CO2 in the atmosphere was steady for centuries at 270-280ppm. The evidence is much more dramatic when linked to temperature rise.
How the link is measured
Scientists have noticed that the average temperature has been rising as there is more CO2 in the atmosphere. One way of finding this out is to drill ice cores from deep within glaciers. In the older ice at the bottom of the tube, the bubbles of trapped atmosphere contain less CO2. Scientists have also noticed that the temperature was lower when there was less CO2 in the atmosphere.
From evidence like this, scientists have been able to see that the temperature gets hotter when there's more CO2 around. The atmosphere can only take so much CO2 before serious changes start to happen.
Unparalleled climate change
The rate at which the world's climate is now changing is unprecedented in human history. The Intergovernmental Panel on Climate Change (IPCC's) report has assessed that: "Mankind's industrial emissions have had five times more effect on the climate than any fluctuations in solar radiation."
The whole world is experiencing extreme weather events. Climate change is happening as you read this. Recent events show how how unpredictable weather can cause chaos on a massive scale - for example, the hurricanes and floods in the USA and the UK, droughts and famine in East Africa, heat-waves in Europe in 2003 and 2006, rising tides in Bangladesh and melting ice-caps. Though we can't blame all of this on climate change, it will make these kinds of events more likely.
Scientists united
The most authoritative source for climate change data is the United Nations Intergovernmental Panel on Climate Change (IPCC) - a group of 2,500 scientific experts from 130 countries. Their fourth and most recent report, published in February 2007 following six years of research, states that:
'It is very likely that [man-made] greenhouse gas increases caused most of the average temperature increases since the mid-20th century.'
What might happen
Climate change affects us all in different ways, but overall, the world is getting hotter. 12 of the past 13 years have been the warmest since records began in 1880. Scientists predict that the planet will be 3 °C (5.4 °F) hotter by 2100. The worst case scenario is a global temperature increase of up to 5 °C (9 °F). This data comes from the most recent report from the IPCC.
In general, those who depend on glaciers for their water will lose their supply, for example, millions of people in China. It's predicted that melting glaciers could cause water shortages for one in six of the world's population. If sea levels rise by 2mm a year as predicted, our coastlines could change dramatically, which is bad news for low-lying countries like Bangladesh and the Maldives. Farmers depend on stable weather to grow their crops, so some food supplies are in danger.
We've put enough CO2 and methane into the atmosphere now to guarantee that some changes will happen. It's estimated that CO2 emitted into the atmosphere today could impact on climate change for up to two centuries. But if we can slow down the rate of change, by reducing how much of these greenhouse gases we produce, we'll be able to cope more easily with what's to come.
Scientific Response to "The Great Global Warming Swindle"
Compiled by University of Cambridge Programme for Industry. Editor: Claire Parker, Environmental Policy Consultant. The Cambridge Programme for Industry co-ordinated a formal scientific-based response "The Great Global Warming Swindle"to the Channel 4 Swindle Programme shown in March 2007.
What can I do?
To get ideas on how to tackle climate change, take a look at the Take Action section on this site. These pages describe over 30 ways for individuals and small businesses to play a part in reducing the impacts of climate change and creating a better world. Actions range from easy steps such as signing up to renewable energy or collecting rain water in a garden water butt, to travelling by train instead of flying.
We've all thought, 'What difference can I make by recycling one plastic bottle? By drying my washing outside? By not taking the car to work today?' Well, multiply your action by all the actions of everyone worldwide. It all adds up." Alistair McGowan, comedian
Links
For more information on climate change, visit our useful links page.
