Beginner's guide to Climate Change, Global Warming, and the Greenhouse Efect

The Greenhouse Effect
Our nearest neighbour the Moon is very different to the Earth. Under the intense glare of the Sun midday temperatures can reach 101°C only to plummet to -184°C by midnight. Wherever there is sunlight there are also lethal levels of radiation. Our planet by comparison is positively welcoming. The hottest recorded temperature is 70°C and the coldest -89°C. Most inhabited areas are in the range of 40°C to -40°C. Most of the harmful solar radiation never reaches the planet's surface.

The reason for this difference is our atmosphere. This layer of gases surrounds our globe, prevented from escaping by the force of gravity. It is so thin that 90% of it is less than 10 miles above the surface yet it sustains billions of people, and incalculable numbers of plants and animals. It deflects or absorbs large amounts of the Sun's energy and harmful radiation preventing it from reaching the surface during the day. At night, when the heat of the surface radiates out into the cold of space, our atmosphere traps a portion of it keeping the Earth warm, about 20°C - 30°C warmer than it would be otherwise, a process known as the 'greenhouse effect.'

How effectively the greenhouse effect works depends on the mixture of gases in the atmosphere. Different gases absorb different amounts of radiation from different parts of the spectrum, so the more diverse the mixture of gases the wider the range of energy that is trapped.

The major gases in atmosphere, Nitrogen and Oxygen, do not contribute towards the overall warming effect, it's the trace gases that form about 1% of the atmosphere that are significant. Water in the form of vapour or cloud is the most significant naturally occurring 'greenhouse gas.' The other major contributor is Carbon Dioxide, with Methane, Ozone, Nitrous Oxide and Hydrocarbons all having some effect. Some of these gases contribute a lot despite very being present in very small concentrations, for instance Methane is 21 times more effective at trapping heat than Carbon Dioxide, Nitrous Oxide is 310 times more effective.

Global Warming
Over the last 200 years the average temperatures of oceans and near-surface air have been rising all over the world. This is what is known as 'global warming.' There are some skeptics who question whether this warming is occurring at all, questioning the accuracy of measurements or suggesting local factors such as the so called Urban Heat Island Effect, but these arguments have been discounted to most peoples satisfaction.

The main focus of debate currently relates to whether or not the observed Global Warming is, at least in part, the result of human activities or if it is solely the product of natural processes beyond our control. The large majority of scientific opinion believes that Global Warming is being driven by the emission of greenhouse gases into the atmosphere by human activities. These are known as 'anthropogenic' emissions of greenhouse gases. Some believe Global Warming is totally due to human activity, others that a natural process continuing from the end of the last "ice-age" [sic] is being exaggerated by 'anthropogenic' emissions.

Skeptics argue that the climate is too large a thing to be influenced by human behaviour. Various arguments challenging the accepted viewpoint seek to identify flaws in the science. Examples include questioning the impact of changes in the total atmospheric quantity of  Carbon Dioxide and other greenhouse gases, given that they form such a small part of the atmosphere.  Others cite the effect of other factors on the climate, such as changes in sunspot activity or in the orientation of the Earth's rotational axis.

Skeptics and believers have been engaged in an often bitter struggle to influence politicians and public opinion. The believers argue that the skeptics are often motivated by defending petrochemical, car and energy corporations; or else just simply don't like the implications for their lifestyle if the scientists are correct about CO2. The skeptics argue that the scientists have been wrong in the past and that the subject is being hijacked by environmentalists motivated by anti-capitalist and anti-globalisation sentiments.They also accuse them of having a vested interest in that in supporting the anthropogenic explanation more climate scientists are needed to monitor the situation, meaning more work for the scientists supporting this explanation.

The United Nations' Environment Programme and the World Meteorological Organisation established the Intergovernmental Panel on Climate Change (IPCC) in 1988 to provide the world with a clear scientific view on the current state of climate change and its potential environmental and socio-economic consequences. It's 2007 report on Climate Change significantly altered the political landscape and won the organisation the Nobel Peace Prize. The work of the IPCC has helped to spread understanding of the consequences of Global Warming, particularly its implications for local climates with the increased temperatures altering established patterns, a process known as Climate Change.

The IPCC doesn't do it's own research but instead is a panel of scientists who review the various scientific sources available and aim to reach a consensus on what the overall picture arising from the field of climate science is telling us. The IPCC strongly supports the majority viewpoint and has attracted criticism from skeptics who believe that the scientists who are part of the IPCC are part of the group of people 'pushing' the anthropogenic interpretation of global warming and are therefore not independent as they have a vested interest in the results of scientific experiment being interpreted in a certain way.

The Associated Press reports that "Climate scientists have now seen the man-made fingerprint of global warming on 10 different aspects of Earth's environment: surface temperatures, humidity, water vapour over the oceans, barometric pressure, total precipitation, wildfires, change in species of plants in animals, water run-off, temperatures in the upper atmosphere, and heat content in the world's oceans."

Climate Change
A warmer atmosphere means a warmer world. As it heats up, local climate changes providing conditions that better suit some forms of life, but which are harmful to others. If you're a bird that flies, you might well be able to move to somewhere where the conditions suit you better. If you're a tree, you might be doomed.

On a global scale a warmer atmosphere means melting glaciers and polar ice, and more energetic weather patterns leading to greater variation in weather and more frequent and intense storms. It will also alter the availability of fresh water and raise sea levels. Bizarrely, for some locations, a warmer world might mean a colder climate as the effects of heating alter processes that bring warmth to the area, such as the Atlantic current that provides a warmer climate to North Western Europe.

Many might ask what is the problem with Climate Change? The world is a little warmer, but who wants to be cold? Surely a rise of a few degrees Celsius might be a good thing? Well to a certain extent it depends on who and where you are. If you live in some of the more temperate parts of the world and you have a high standard of living it's quite likely that you can deal with the changes in your local climate, unless perhaps your home is just above the current sea-level or your income is dependent upon a climate sensitive crop. One thing is for sure though, the impact of climate change may well cost you money in the taxes required to preserve your way of life and the raised cost of many foods and goods.

If however you're poor and live in an already hot location you might find your land turning to desert or disappearing under the sea, and find your government does not have the resources to help you. The effects of climate change could stimulate unrest with the possibility that in the future riots and wars may wage over access to drinking water, food or fertile land. Millions may become refugees from land that can no longer support them living in conditions conducive to the creation and exporting of terrorism targeted at rich nations viewed as causing the problems but not suffering the consequences.

In conclusion
Climate science is very complicated and millions of dollars have been invested by various lobbying groups to ensure their interpretation of the science wins the day. For the individual it can seem overwhelming and very difficult to understand the intricacies. However, with a willingness to seek out the information the main concepts are fairly easy to grasp and I believe anybody can develop their understanding to a level that allows them to appreciate the implications of climate change and understand what changes will need to be made if they accept the anthropogenic explanation for global warming.

Further information
To find out more on this subject I recommend the following resources:

The Rough Guide to Climate Change
A very good book that explores the subject including the arguments of the skeptics.

The A-Z of Global Warming
An examination of Global Warming in a useful A-Z format. A great reference book for dipping into whenever a particular issue such as Electric Vehicles or Carbon-Dioxide come up.

The Republican War on Science
This book looks at how the political right in the USA has used misinformation and bad science to support political decisions. While an interesting book in its own right, it's also a good introduction to the methods that any lobby group of any political persuasion may use to try and use science to support and promote their agenda.

Earth : The Power of the Planet
Not directly about Global Warming and Climate Change, this DVD set looks at the processes at work on the Earth affecting the environment and climate across the history of the planet. These DVDs provide an excellent background against which to consider the current processes at work associated with Climate Change.

The Age of Stupid
A dramatisation looking at the issues of Climate Change from the perspective of a man living in the year 2055. Thought provoking entertainment.

The UK Met Office Climate Change site
The Met Office's website on Climate Change is an excellent resource for individuals and businesses.

The Royal Society Climate Change website
An excellent information site from the UK & Commonwealth's respected academy of science. Particularly interesting are its sections on "Facts and fictions about climate change" and "Climate change controversies: a simple guide."
Major site run by climate scientists attempting to provide clear analysis of issues and controversies in climate science.
Long established sceptical site which covers the main areas currently being contested.