Know Climate Change

Science behind Climate Change


What is Climate Change?

Since the end of the 19th century, the earth's average surface temperature has increased by 0.3-0.6 °C. Over the last 40 years, the rise has been 0.2-0.3 °C.

Global sea level rose by about 17 centimetres (6.7 inches) in the last century. In the last decade, however, the rate of rise has nearly doubled.

The Greenland and Antarctic ice sheets have shrunk in both area as well as mass.

Mountain glaciers and snow cover have declined on average in both hemispheres, and may disappear altogether in certain regions of our planet, such as the Himalayas, by 2030.

What do the above facts indicate?

Yes! The climate is changing.

Climate change refers to a statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (decades or longer).


IPCC's Point of View

The IPCC (Intergovernmental Panel on Climate Change) refers to climate change as variation in either the mean state of the climate or in its variability, persisting for an extended period. Climate change may be due to natural internal processes or external forcings, or due to persistent anthropogenic changes in the composition of the atmosphere or in land use. Thus, IPCC usage refers to any change in climate over time, whether due to natural variability or as a result of human activity.

UNFCCC's Point of View

UNFCCC (United Nations Framework Convention on Climate Change) attributes climate change directly or indirectly to human activities that alter the composition of the global atmosphere and that is in addition to natural climate variability observed over comparable time periods. The human influence on the climate has increased tremendously since the pre-industrial times due to an increase in GHG (greenhouse gas) emissions, which has resulted in high GHG concentration levels in the atmosphere due to the long atmospheric residence time of GHGs. This human-induced increase in GHG emissions, and the associated climate change, is what is preoccupying the world's attention, as it is largely the human-induced climate change that we can control.