Global warming refers to the increase in the average temperature of the Earth’s near-surface air and oceans in recent decades and its projected continuation.
The phenomenon is believed to have increasing effects on both the natural environment and human life.
During the 20th century alone, the Earth’s surface warmed by about 0.6ºC. Scientists have been speculating whether this global warming has been caused by the enhanced greenhouse effect. Climate models are used to detect a human fingerprint in the climate. As their reliability has improved, the link between greenhouse gas pollution and global warming has been strengthened.
Climate Change is characterized as any long-term significant change in the “average weather” that a given region experiences. Average weather may include average temperature, precipitation and wind patterns. It involves changes in the variability or average state of the atmosphere over durations ranging from decades to millions of years. These changes can be caused by dynamic processes on Earth, external forces including variations in sunlight intensity, and more recently – according to more and more climatologists – increasingly by human activities, causing an Advanced or Enhanced Greenhouse Effect, a major human influence on the Global Warming phenomenon.
The (normal or natural) Greenhouse Effect was discovered by Joseph Fourier in 1824 and was first investigated quantitatively by Svante Arrhenius in 1896. It is the process by which absorption and emission of infrared radiation by naturally occurring atmospheric gases warms a planet's atmosphere and surface to a mean temperature of about 33 °C (59 °F), without which Earth would not be habitable.
The problem lies in the human induced increase of greenhouse gases. From the end of the last Ice Age episode about 10,000 years ago until the end of the 18th century, the levels of greenhouse gases in the atmosphere remained fairly constant. Since the Industrial Revolution, however, 200 years ago, mankind has been releasing extra quantities of greenhouse gases into the atmosphere, which trap more heat, enhancing the natural greenhouse effect. Processes such as the burning of fossil fuels, industrial operations and forest clearing release carbon dioxide, methane and nitrous oxide into the atmosphere. Chlorofluorocarbons, or CFCs, are also potent greenhouse gases, and as an added danger, they destroy the ozone layer.
Emissions of these gases are expected to continue raising average earth temperatures over the coming decades. In addition, emerging economies are spurring a soaring demand for energy and need to increase current production levels considerably. The International Energy Agency, among many other equally qualified environmental organizations, warns that sweeping changes in the electricity and auto industries will be necessary if the world is to successfully halve its CO2 emissions by 2050.