This article contains information about climate change.  Source: direct.gov.uk

-Brief history of climate change

-Effects of climate change

-Causes of climate change

-Myths about climate change


1. Brief history of climate change

Tackling climate change is one of the biggest challenges this generation faces, and the first step is to understand exactly what it is. Find out how climate change was first detected, the history of efforts to tackle it and the latest developments.

1.1. what is climate change?

The climate is not static; over the millions of years of earth’s existence, it has changed many times in response to natural causes.

When people talk about 'climate change' today, however, they mean the changes in temperature over the last 100 years. During this time, the average temperature of the atmosphere near the earth’s surface has risen by 0.74 degrees Celsius.

Most scientists agree that global temperatures will rise further – by how much depends on future emissions of greenhouse gases. If the temperature rise is high, changes are likely to be so extreme that it will be difficult to cope with them. There are likely to be more intense and frequent extreme weather events, like floods and hurricanes, and sea levels could rise further.

1.2 Early discovery about Climate Change

The first discoveries that helped explain climate change happened in the 18th and 19th centuries:

-in 1753, Joseph Black discovered carbon dioxide

-in 1827, Jean-Baptiste Fourier suggested that an atmospheric effect kept the earth warmer than it would otherwise be – he used the analogy of a greenhouse

-in 1896, Arrhenius proposed that carbon dioxide emissions from the burning of coal would enhance the earth's greenhouse effect and lead to global warming

1.3 First warnings about climate change

In 1967, a computer simulation calculated that global temperatures might increase by more than four degrees Fahrenheit, depending on carbon dioxide levels.

20 years later, an ice core from Antarctica revealed a link between carbon dioxide levels and temperature going back more than 100,000 years. Warnings like these encouraged international action on climate change.

1.4 The world´s response to climate change

In 1979, the world held its first climate conference. The conference called on governments “to foresee and prevent potential man-made changes in climate”.

United Nations takes action
In 1988, the United Nations set up the Intergovernmental Panel on Climate Change (IPCC) to analyse and report on scientific findings. The IPCC warned that only strong measures to stop greenhouse gas emissions would prevent serious global warming.

Global targets for reducing emissions
In 1992, the Earth Summit took place in Rio de Janeiro. Here, the United Nations Framework Convention on Climate Change (UNFCCC) was signed by 154 nations. It agreed to prevent 'dangerous' warming from greenhouse gases and set voluntary targets for reducing emissions. The UK is one of a small number of countries which met this voluntary target.

Kyoto: legally binding cuts in emissions
In 1997, the Kyoto Protocol was agreed. Where the UNFCCC agreed voluntary targets, Kyoto was the first international treaty to set legally binding emissions cuts for industrialised nations. It was signed by 178 countries and came into force in 2005.

1.5 The UK’s reaction to climate change

The UK signed both the UNFCCC and the Kyoto Protocol, and is on track to exceed its Kyoto target for reducing greenhouse gas emissions.

In 2006, the Stern report was published in the UK by HM Treasury. It was the first report of its kind into the economic impact of climate change. It found that the costs of inaction far outweighed the costs of action.

In November 2008, the UK government passed the Climate Change Act. The Act sets legally binding targets for reducing emissions by 80 per cent on 1990 levels by 2050.

1.6 Latest international action on climate change

In 2007, the IPCC announced that the planet has warmed 0.74 degrees Celsius since the beginning of the 20th century. It said there is a greater than 90 per cent chance that global warming over the last 50 years is due to human activity.

At the 2007 UN climate change conference in Bali, the world’s nations agreed to negotiate on a deal to tackle climate change. This agreement would replace the Kyoto Protocol and the details are expected to be agreed at Copenhagen in 2009.

2. Effects of Climate change

The effects of climate change can be seen in the UK and around the world. Already, British coastal waters have warmed and temperatures have risen. Globally, extreme weather is predicted to become more common – and animals, plants and crops are all expected to be badly affected.

2.1 Rising temperatures

The 1990s was the warmest decade in central England since records began in the 1660s. Summer heatwaves are now happening more frequently and in winter there are fewer frosts.

Globally, over the past century, the average temperature of the atmosphere near the earth’s surface has risen by 0.74 degrees Celsius. Eleven of the 12 hottest years on record occurred between 1995 and 2006.

The scientific consensus is that global temperatures could rise between 1.1 and 6.4 degrees above 1980-1999 levels by the end of the 21st century. The exact amount depends on the levels of future greenhouse gas emissions.

2.2 Changing sea levels and temperatures

The sea level around the UK has risen.

UK coastal waters have warmed by about 0.7 degrees Celsius over the past three decades. In addition, the average sea level around the UK is now about 10 cm higher than it was in 1900.

Globally, the sea level could rise by 18 to 59 cm by the end of the century. Rising sea levels would swamp some small, low-lying island states and put millions of people in all low-lying areas at risk of flooding.

You can use Google Earth to see how climate change could affect temperatures and ice caps over the next century. Google Earth also lets you view the loss of Antarctic ice shelves over the last 70 years.

2.3 Extreme weather

Since rain records began in 1766, the amount of winter rainfall in England and Wales has risen. Over the last 45 years it has also become heavier; in 2000, UK flooding was the worst for 270 years in some areas. Flood damage now costs Britain about £1 billion a year.

Globally, climate change means that extreme weather events – like floods, droughts and tropical storms – will become more frequent and dangerous.

2.4 Plants and animals

A global temperature rise could make some species extinct

There are already changes to the way plants and animals live in this country. The period between spring and autumn when plants grow is now a month longer in central England than it was in 1900.

Further changes in rainfall and temperature will affect many animal and plant species around the world. Some species might be unable to adapt quickly enough and habitats might not be available for them to move into. If global temperatures rise by two degrees Celsius, 30 per cent of all land-living species will be threatened by an increased risk of extinction.

2.5 The cost of climate change

The Association of British Insurers estimates that UK households will pay up to four per cent extra each year due to extreme weather events.

The costs of climate change are expected to be huge, as the Stern report on the economics of climate change makes clear. The report estimates that not taking action could cost from five to 20 per cent of global GDP every year, now and in the future. In comparison, reducing emissions to avoid the worst impacts of climate change could cost around one per cent of global GDP each year.

2.6 Food and water

As temperatures increase and rainfall patterns change, crop yields are expected to drop significantly in Africa, the Middle East and India.

Water availability for irrigation and drinking will be less predictable because rain will be more variable. It is also possible that salt from rising sea levels may contaminate underground fresh water supplies in coastal areas. Droughts are likely to be more frequent. Up to three billion people could suffer increased water shortages by 2080.

2.7 Disease

With rising temperatures, diseases like malaria, West Nile disease, dengue fever and river blindness will shift to different areas. It is predicted that 290 million additional people could be exposed to malaria by the 2080s.

2.8 Rainforests

Large areas of Brazilian and central African rainforest could be lost if climate change results in big falls in rainfall in these areas. This would be on top of the forest already being cut down to clear land for agriculture. These forests currently absorb large amounts of carbon dioxide that would otherwise be released into the atmosphere.

3. Causes of climate change

There is very strong evidence that people are changing the climate with actions which create emissions of greenhouse gases like carbon dioxide and methane. In the UK, 40 per cent of these emissions are caused by individuals, mostly from energy used in the home, driving and air travel.

3.1 Natural causes or human activity?

Human activity is the main cause of the changes seen in climate

The world's climate varies naturally as a result of:

-the way the ocean and the atmosphere interact

-changes in the earth's orbit

-changes in energy received from the sun and volcanic eruptions

However, there is now strong evidence and almost universal agreement that significant global warming can’t be explained just by natural variations. The changes seen over recent years, and those predicted for the next 80 years, are thought to be mainly as a result of human behaviour.

The Intergovernmental Panel on Climate Change (IPCC) is a scientific body set up by the UN to look at climate change. It says that human activity is the main cause of the changes seen in climate.

3.2 The greenhouse effect

The earth is surrounded by a layer of gases which act like the glass walls of a greenhouse. These gases let the sun’s rays enter, but stop much of the heat from escaping. This is a natural process, and it’s these ‘greenhouse gases’ (mainly carbon dioxide and water vapour) that keep the planet warm enough to sustain life.

However, as humans cause more greenhouse gases to be released into the atmosphere, the greenhouse effect becomes stronger. More heat is trapped and the earth's climate begins to change unnaturally.

Since the Industrial Revolution, which began in the 18th century, the amount of carbon dioxide (CO2) in the atmosphere has increased by 35 per cent. In fact, the concentration of CO2 is now higher than at any point in the past 650,000 years.

3.3 Why greenhouse gases have increased

Deforestation produces 18 per cent of global CO2

Human activity is changing the amount of greenhouse gases in the atmosphere in three important ways:

3.3.1. Forests are being cut down
Trees absorb carbon dioxide so, with fewer trees, more carbon dioxide builds up in the atmosphere. Also, the agriculture and industry that replaces the forests can often be a source of emissions. The Intergovernmental Panel on Climate Change (IPCC) estimates that deforestation produces 5.9 billion tonnes of CO2 per year or 18 per cent of global CO2.

3.3.2. Fossil fuels are being burned
Burning fossil fuels like coal, oil and gas - to generate heat or to power transport for example - releases greenhouse gases. In 2005, burning fossil fuels emitted about 27 billion tonnes of carbon dioxide.

3.3.3. The world’s population is growing
A growing population is leading to an increased demand for food, livestock and energy, which is in turn leading to increased emissions.

3.4 The main contributors to climate change in the UK

In the UK, around:

    * 4 per cent of emissions come from industrial processes
    * 7 per cent are from agriculture – for example methane emissions from livestock and manure, and nitrous oxide emissions from chemical fertilisers
    * 21 per cent are from transport
    * 65 per cent come from the use of fuel to generate energy (excluding transport)

About 40 per cent of emissions in the UK are the result of decisions taken directly by individuals. The biggest sources of emissions for most people are likely to be:

    * energy use in the home (the main use is heating)
    * driving
    * air travel

Other things in people's homes contribute to climate change indirectly. Everything, from furniture to computers, from clothes to carpets, uses energy when it is produced and transported – and this causes emissions to be released.

4. Myths about climate change

Confusion and myths about climate change are widespread. This section aims to explore some of the most common misconceptions and the facts behind them.

4.1 The climate is always changing anyway

There is more carbon dioxide in the atmosphere now than at any point in the last 650,000 years

It’s true that natural changes in the world's climate have happened in the past – but it is sometimes overlooked that in extreme cases this resulted in mass extinctions. What is happening now is potentially a big change in the climate that humans have caused.

Carbon dioxide is a major heat-trapping greenhouse gas and its concentration in the atmosphere is now higher than at any point in the last 650,000 years. Although this is not new in the history of the planet, it is entirely new in human history, and could make the world such a hostile place that it cannot support life.

4.2 There's no scientific evidence for climate change

Scientists have been commenting on the relationship between emissions of gases and the climate since the 1800s, and have worked with governments to do something about climate change for a long time.

In 1988, the UN set up the Intergovernmental Panel on Climate Change (IPCC) – a body of scientists from all parts of the world who assess the best available scientific and technical information on climate change.

Their 2007 report warned of an increase in average global temperatures ranging from 1.1 to 6.4 degrees Celsius by the end of this century, depending on future levels of emissions. It also said that changes to the climate were "very likely" (over 90 per cent probable, based on current science) the result of human activity.

4.3 Climate change isn't caused by human activity

Most scientists are convinced that humans are affecting the climate by the way they live.

The majority of scientists are convinced that humans are affecting the climate by the way they live. The Met Office Hadley Centre is the UK’s official centre for climate change research. They recently carried out a study that found today’s temperatures could only be the result of human activity.

Science has shown that greenhouse gases keep the earth warm, that there is evidence concentrations of these gases are increasing, and that humans are responsible for these increases by burning fossil fuels and cutting down forests.

4.4 It's too late to make a difference

The last report from the IPCC indicated that global emissions must peak in the next decade or two and then decline to well below current levels by the middle of the century if we are to avoid dangerous climate change.

This is possible, and can be achieved with technologies that are available now. Putting off action to cut greenhouse gases will make it more difficult and costly to reduce emissions in the future, as well as creating higher risks of severe climate change impacts.

4.5 There's no point in me taking action

Every reduction in emissions makes a difference by not adding to the risk. Countries like the UK are in a position to give a positive example to the rest of the world – if the UK can rise to the challenge successfully, others will follow.

4.6 Climate change will make life more comfortable in the UK

Climate change will lead to warmer winters, but temperatures will become uncomfortably hot in summer, and the climate may also be unpredictable and extreme. There's also the risk of rising sea levels and extreme weather like storms and floods. Tackling climate change and securing a more stable climate will make life a lot more comfortable.

4.7 It would cost too much to tackle climate change

Tackling climate change needn’t damage the economy as a whole. Industry will have to adapt and jobs may change – but more may be created overall. Using less energy can also save companies and households money.

Not tackling climate change has a price too. The recent Stern report examines the economic impact of climate change. It estimates that not taking action could cost from five to 20 percent of global GDP every year, now and forever. In comparison, the cost of reducing emissions to avoid the worst impacts of climate change can be limited to around one per cent of global GDP each year.


Image credit:

Image: Arvind Balaraman / FreeDigitalPhotos.net