Climate change is here

Climate change is not an easy word. On one hand, it means all climate changes that have occurred in the history of earth. On the other hand, it is also used to describe the currently occurring change of the climate that is caused by humans.

There have always been changes of the climate. The average temperature of the earth has changed slightly due to changes in the axis of the earth, which has resulted cooler and warmer periods.

How does the current climate change differ from the past changes then?

The greenhouse effect

When humans produce greenhouse gases, like carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), more heat gets trapped in the atmosphere, causing the earth to warm, similarly as the greenhouse stores heat. The increasing of greenhouse gases enhances this natural phenomenon, so that less heat reflects back into the space, causing the earth's temperature to rise. It must be remembered though that there would be no life on earth without the greenhouse effect. Instead, earth's average temperature would be approxiately-18 degrees Celsius.

The amount of carbon dioxide has tripled during the industrial era, and the amount of methane has nearly doubled. It has been estimated that carbon dioxide levels are presently at the highest level in 20 million years.

Greenhouse gas sources

Humans produce carbon dioxide by burning fossil fuels like oil, natural gas and coal. Deforestation and peat production also increase the amount of carbon dioxide in the atmosphere. Carbon dioxide is the most significant greenhouse gas whose atmospheric concentration humans affect.

Methane is the second most important greenhouse gas. It breaks down faster than carbon dioxide, but its effect is about 14 times stronger than that of carbon dioxide. Fossil fuels are a source of methane, but also landfills are a significant source of methane today.

Nitrous oxide, or laughing gas, is the strongest greenhouse gas out of the five natural greenhouse gases. It is 300 times stronger than CO2. Nitrous oxide is released from nitrogen fertilizers, energy production and nitric acid production

The proofs of change

Climate change sceptics claim that the current warming occurs due to natural temperature variation of the earth. This is partially true, but it has been noticed that when you compare the current situation to climate change forecasts and models, the current warming cannot be explained with anything else but human activities.

The researches of the IPCC (Intergovernmental Panel on Climate Change) have noticed that the correlation between natural causes (like volcanic activity and the amount of solar radiation) and warming of the earth to be weak. Instead, the correlation between increasing greenhouse gas concentration and warming of the earth to be significant.

Signs of change

Climate change causes different problems in different parts of the world. Glaciers recede, water surfaces rise, species change and extreme whether conditions increase. The greatest concern is the extreme nature and unpredictability of the changes. When it is not known how different parts of the world will react to the change, it is not possible to prepare for the problems either.

THEREFORE, CLIMATE CHANGE HAS TO BE ADDRESSED BOTH LOCALLY ANG GLOBALLY!

12.9.2005 Anna Koivisto