hekki

Page 1 of 3

hekki

By | October 2013
Page 1 of 3
GLOBAL CLIMATE CHANGE AND ITS IMPACT
- Harshit Sharma
12th C
Identifiable change in the climate of Earth as a whole that lasts for an extended period of time (decades or longer) is referred as climate change. When due to natural processes, it is usually referred to as global climate variability. Usually refers to changes forced by human activities that change the atmosphere. Climate change is a long-term shift in weather conditions identified by changes in temperature, precipitation, winds, and other indicators. Climate change can involve both changes in average conditions and changes in variability. The earth's climate is naturally variable on all time scales. However, its long-term state and average temperature are regulated by the balance between incoming and outgoing energy, which determines the Earth's energy balance. Any factor that causes a sustained change to the amount of incoming energy or the amount of outgoing energy can lead to climate change. As these factors are external to the climate system, they are referred to as 'climate forcers', invoking the idea that they force or push the climate towards a new long-term state - either warmer or cooler depending on the cause of change. Different factors operate on different time scales, and not all of those factors that have been responsible for changes in earth's climate in the distant past are relevant to contemporary climate change. Factors that cause climate change can be divided into two categories ­- those related to natural processes and those related to human activity. In addition to natural causes of climate change, changes internal to the climate system, such as variations in ocean currents or atmospheric circulation, can also influence the climate for short periods of time. This natural internal climate variability is superimposed on the long-term forced climate change. The Earth's climate can be affected by natural factors that are external to the climate system, such as changes in...