Page 24 - Alternative Energy Systems in Building Design

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GLOBAL WARMING: CLIMATIC

AND ATMOSPHERIC CHANGES

Climate change refers to variation in global or regional climates over time. It describes
variability in the average state of the atmosphere over time periods ranging from decades
to millions of years. These changes can be caused by internal processes in the earth or
by external forces such as variations in sunlight intensity and, more recently, human
activity.
In the context of, the term climate change often refers to changes in modern climate
that are likely caused in part by human, or anthropogenic, action. Climate change is
frequently referred to as global warming. In some cases, this term is used with a
presumption of human causation for variations that are in actuality not anthropogenic.

Climate Change Factors

Climate changes reflect variations within the earth’s atmosphere, processes in parts of
the earth such as the oceans, and and the effects of human activity. Other external factors
that affect climate are referred to as climate forcing factors, which include variations
in the earth’s orbit and greenhouse gas concentrations.

Variations within the Earth’s Climate

Weather change is a normal state of the atmosphere and appears to have unpredictable
dynamics. However, from a climatic point of view, the average state of weather is rela-
tively stable and predictable. Climate change is measured by the average temperature,
amount of precipitation, days of sunlight, and other variables at a particular region of the
globe. Earth’s climate is also subject to change from within owing to glaciation, oceanic
temperature variability, and myriad other factors.

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