Climate Change : Reality or Assumption?
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Climate in a narrow sense is usually defined as the "average weather," or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands of years. The classical period is 3 decades, as defined by the World Meteorological Organization (WMO). These quantities are most often surface variables such as temperature, precipitation, and wind. Climate in a wider sense is the state, including a statistical description, of the climate system
Climate Change: Climate change refers to any significant change in the measures of climate lasting for an extended period of time. In other words, climate change includes major changes in temperature, precipitation, or wind patterns, among others, that occur over several decades or longer.
The major reason for climate change is Greenhouse Effect which occurs due to modernization, industrialization, increasing population growth & deforestation by the human activities. Greenhouse gases are Carbon dioxide (co₂), Methane (CH₄), Nitrous Oxide (N₂O), Fluorinated gases like Hydroflurocarbons, Perflurocarbons etc. Carbon dioxide contributes about 74% reasons for global warming i.e. about 57% by fossil fuels use & about 17% by deforestation, natural biomass decay etc. Methane contributes about 14 % & Nitrous oxide contributes about 8% of global warming. Remaining 1 % cause is fluorinated gases.
Emission of Green house gas from different sector (Kyoto Protocol)
Thermal plant: 24.5%
Deforestation and Degradation: 17.4 %
Agricultural area : 13.5%
Settlement : 9.9%
Waste water: 2.8%
Is Climate Change Happening?
There is a strong scientific consensus that the global climate is changing and that human activity contributes significantly to this trend. This consensus was confirmed by the WMO/UNEP Intergovernmental Panel on Climate Change (IPCC) in September 2013, when it finalized The Physical Science Basis volume of the Fifth Assessment Report (AR5). The report concludes that the “Human influence on the climate system is clear. This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system.”
The report further states that “It is extremely likely [defined as 95-100% certainty] that human influence has been the dominant cause of the observed warming since the mid-20th century.”(WMO Information Note, November, 2013)
Small changes in the average temperature of the planet can translate to large and potentially dangerous shifts in climate and weather. Earth's average temperature has risen by 1.4°F (0.8°C) over the past century & it is projected to rise another 1.1°C to 5.8°C over the next hundred years. IPCC reports say Climate Change is Unequivocal.
Some evidences by NASA that climate change is happening are as follows:
- Sea level rise –Global Sea rise about 17cm (6.7 inches) in last century whose rate is nearly double of last century.
- Earth has warmed since 1880 A.D. 20 warmest years occurred since 1881 with all 10 warmest years occurring in past 12 years.
- Ocean temperature of top 700 m has warmed by 0.302 degree Fahrenheit since 1969.
- Continuous melting of ice of Antarctica.
- Glacier outbursts in the Alps, Himalayas, Andes, Rockies, Alaska & Africa.
- Ocean Acidification –Since Industrial revolution acidity of ocean water has increased by 30% as a result of more co₂ in atmosphere & oceans absorbing them.
There is still many more evidence that climate change is occurring. Several reports published by World Meteorological Organization (WMO), National Aeronautics and Space Administration (NASA), Intergovernmental Panel on Climate Change (IPCC), United Nations Framework Convention on Climate Change (UNFCC) etc. have mentioned that climate change is occurring in the world.
Personally, I also believe that climate change is occurring. But there are some scientists in the world who believe that climate change is not occurring & present some reasons behind their arguments.
What do you feel about Climate change? It is occurring or
WMO Information Note, November 2013
IPCC 4th report, 2007