Global Warming & Climate Change
Global warming and climate change refer to an increase in average global temperatures. Generally, the natural events and human activities are believed to be contributing to an increase in average global temperatures. This is caused primarily by increases in “greenhouse” gases such as Carbon Dioxide (CO2).
To understand the phenomena of climate change and global warming, clarity in the concept of climate system is necessary. The climate system is a complex system consisting of the atmosphere, land surface, snow and ice, oceans and other bodies of water, and living things. The climate is often defined as ‘average weather’. It is usually described in terms of the mean and variability of temperature, precipitation and wind over a period, ranging from months to millions of years.
The climate system evolves under the influence of its own internal dynamics and to changes in external factors that affect climate (called ‘forcings’). External forcing includes natural phenomena such as volcanic eruptions and solar variations, as well as human-induced changes in atmospheric composition. Solar radiation powers the climate system.
‘Climate change’ refers to a change in the state of the climate that can be identified by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer. Climate change may be due to internal processes and/or external forcings. Some external influences, such as changes in solar radiation and volcanism, occur naturally and contribute to the changes in the climate system. It has been established that human activity also contributes to such changes.