The term 'Climate Change' is commonly used interchangeably with "global warming" and "the greenhouse effect". It refers to the buildup of man-made (greenhouse) gases in the atmosphere that trap the suns heat, causing changes in weather patterns on a global scale. The effects include changes in rainfall patterns, sea level rise, potential droughts, habitat loss, and heat stress.

The climate of an area is the average and variations of weather over long periods of time. For example, rainforests are found in tropical climates, where the weather is constantly warm and there are high levels of rainfall. A Mediterranean climate will usually have warm dry summers, and mild and wet winters. Some countries have mostly hot dry weather, experiencing what is called an arid or semi-arid climate.

Here in Ireland, we have a temperate climate, with mild winters and summers, and rain throughout much of the year. However, even in a small country like Ireland, there can be distinct local variations in weather, in particular when looking at rainfall. Where do you think the wettest and driest areas in the country are located?

Greenhouse Effect
There is a blanket of gases surrounding the planet which helps keep the surface of the earth warm enough to sustain life. The gases in the atmosphere, including carbon dioxide, allow sunlight in but trap much of the heat. Were it not for this so-called ‘greenhouse effect', we would live on a much colder planet - the average surface temperature of the Earth would be -18°C. The presence of greenhouse gases in the atmosphere raises the Earth's temperature by 33ºC to its current surface average of 15ºC.

History Of Climate Change
However, it must be remembered that the climate of the Earth has been changing consistently over its 5-billion-year history. Such changes in climate usually occurred very slowly over many thousands of years. They happened primarily as a result of the effects the sun, land, oceans and atmosphere have on each other.

Even in Ireland, we do not have to go too far back in time to find a climate very different from today. The most recent ice-age in Ireland only took place between 30,000 years ago to about 14,000 years ago. Most of the area of Ireland was covered in ice, the sea levels were 50 meters below today's levels, and Ireland was joined to Britain and mainland Europe. As the ice melted across Europe and the world, sea levels rose and Ireland became an island once more. Even as recently as the 14th century, Europeans lived through what is known as the "Little Ice Age."

Why Worry?
So why are we so worried about climate change, if it is something that occurs naturally and has happened throughout the history of the Earth? What impacts are we having through our lifestyles, and can we influence the situation?

The vital difference between the current period of global warming compared to previous cycles of climate change is how quickly the rate of change is happening. The planet has warmed by about 1°C over the past 100 years, and most scientists now agree that this is mainly as a result of the increasing amount of greenhouse gases (particularly CO2) released into the Earth's atmosphere from human activity.

As a result of the billions of tonnes of CO2 (and other greenhouse gases) released globally each year the blanket of gases in the atmosphere is trapping more heat inside, resulting in global warming and unpredictable weather patterns. As far back as 1967 the first reliable computer simulation calculated that global average temperature could increase by more than 4°C when the atmospheric CO2 levels reach double that of pre-industrial times. However, it is only relatively recently that the full extent of the dangers and possible effects of climate change have emerged.

To examine some of the causes of Climate Change click here.

Further Reading:
For some information on Ireland's climate from Met Éireann, click here.

For information on climate change from the Department of the Environment, Heritage and Local Government, click here.

Check out Enfo Ireland's public information service on environmental matters. Go to the site and then click on link for Climate Change.