Climate Change: questions and answers part 4

 Q: Outline the processes that led to the establishment of IPCC and UNFCC and describe how their roles differ?

Ans: The United Nations Framework Convention on Climate Change (UNFCCC) is an international environmental treaty negotiated at the United Nations Conference on Environment and Development (UNCED) and formally known as the Earth Summit which was held in Rio de Janeiro from 3 to 14 June 1992. The main objective of the UNFCCC is to "stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.
The Intergovernmental Panel on Climate Change (IPCC) is a scientific intergovernmental body under the auspices of the United Nations.It was established in year 1988 by two United Nations organizations, the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP). It reviews and assesses the most recent scientific, technical and socio-economic information produced worldwide relevant to the understanding of climate change. It does not conduct any research nor does it monitor climate related data or parameters. The IPCC published its first assessment report in 1990, a supplementary report in 1992, a second assessment report (SAR) in 1995, a third assessment report (TAR) in 2001, a fourth assessment report (AR4) in 2007 and a fifth assessment report (AR5) in 2014.

Q: How does the differentiated availability of energy across the Earth's surface lead to different climates and weather systems around the world?

Ans: The distribution of solar radiation on the Earth's surface regulates the length and order of the seasons. Solar radiation strikes the earth more directly at the equator and tropics than in polar regions. More heat is therefore transferred to Earth in the tropics than at the poles.Global atmospheric circulation patterns represent the planet’s attempt to move warm air toward the poles and cold air toward the equatorial region.

These patterns are complicated by Earth's rotation,dividing into three large convection cells in the  Northern and Southern Hemispheres that control climate patterns. Short-term climate fluctuations occur on cycles lasting thousands of years and are related to variations in Earth’s orbit around the Sun that cause the amount of incoming solar radiation to vary with time. These variations result from changes in the shape of Earth's orbit and changes in the magnitude and direction of tilt of Earth's axis, thus lead to different climates and weather systems around the world.

Q: In the IPCC definition of radiative forcing which is more important, natural or anthropogenic climate forcing factors? Explain.

Ans: Anthropogenic factors are more important according to IPCC definition of radiative forces as follows:

The Industrial Revolution in the 19th century saw the large-scale use of fossil fuels for industrial activities. Natural resources are being used extensively for construction, industries, transport, and consumption.

 Fossil fuels such as oil, coal and natural gas supply most of the energy needed to run vehicles, generate electricity for industries, households, etc. Changes in land use pattern, deforestation, land clearing, agriculture, and other activities have all led to a rise in the emission of carbon dioxide. A large amount of nitrous oxide emission has been attributed to fertilizer application.  The human impact on climate during this era greatly exceeds that due to known changes in natural processes, such as solar changes and volcanic eruptions.

The  differences  in  radiative  forcing  estimates  between  the present day and the start of the industrial era for solar irradiance changes and volcanoes are both very small compared to the differences in radiative forcing estimated to have resulted from human activities. As a result, in today’s atmosphere, the radiative forcing from  human  activities  is  much  more  important  for  current  and future  climate  change  than  the  estimated  radiative  forcing  from changes in natural processes.

Q: From an Earth system feedback perspective which is more likely to increase the impact of global warming over the next 100-200 years: melting polar ice, or changes in cloud cover? Justify your answer.

Ans: Melting polar ice is more likely to increase the impact of global warming over the next 100-200 years, as the ice is disappearing quite fast; not only is albedo decreasing, but the loss triggers a positive feedback. By exposing the ocean surface to sunlight, the water warms up. This melts the ice from underneath, while man-made CO2 in the atmosphere warms the surface.

Humidity also increases; water vapour is a powerful greenhouse gas.  More ice therefore melts, which exposes more water, which melts more ice from underneath. Clouds can increase albedo (a negative feedback), but also warming (a positive feedback), but sea ice is a critical player of Earth's changing climate. Sea ice cools by reflecting incoming solar radiation back into space. Because of its light color, sea ice has what is known as high albedo, which is the percentage of solar radiation a surface reflects back to space.

Q. Attempt to explain the observed acceleration in Arctic summer sea ice loss since about the year 2000.

Ans: Less ice on the surface of arctic in summer and what is there is not thick as it use to be. It's not covering the ocean as it used to be and what ice is there is thin so it melts quickly. If we look at the Arctic summer sea ice loss for subsequent years from 2000 onwards, we can see that it's thinner if we look for a gap of a year only while thicker in case of gap of three years. These trends indicate global see level is increasing in comparison to sea ice. Sea level change in India is about one mm/year.

Q. In the context of climate and weather, give one example of a slow-onset event and one example of a rapid-onset event in your district / country / region in the last 1-5 years. Do you think that the frequency of such events is increasing or decreasing; if you think there is a change do you think it can be linked to global warming; and what do you think is the nature of that link?

Ans:  Slow onset event is melting of ice in India. The ice loss is 1mm/year in India, due to which the sea level is increasing. Rapid onset event is no. of cyclones in India 1- 5 years. Recently, the cyclone affected the major parts of Odisha and Andhra Pradesh in India. The frequency of cyclones increased in last 1-5 years in comparison to previous years.
Yes, the frequency of such events is seen to increase in the last 1-5 years.
Yes it can be linked to global warming, as earth's atmosphere get heated  up due to green house gases as a result of which there is rapid increase in temperature over the recent years. Melting ice and cyclone regarded as natural factors but  as their magnitude is increased due to global warming.