Rethink our actions!!!

One of the global concerns of most nations (both developed and developing) is “Global Warming”. Like a coin has two sides this topic has two approaches, one outlook states that this is a natural phenomena while most strongly believe that the anthropogenic activities have accelerated this process. I believe that the anthropogenic activities are not the solitary contributors of climate change; the natural phenomena’s (plate tectonics, volcanic eruptions, solar variations, and orbital variations, all of which occur over a long period of time) also contribute to a small percentage of climate variations (evident from the RF values).

To correlate global warming with anthropogenic activities one needs to understand the Earth’s energy system and the variations occurring in it. The incoming solar insolation/shortwave and outgoing infrared radiation/longwave should be (on an average) in equilibrium (first law of thermodynamics). These energy fluxes govern the temperature of the Earth’s surface and atmosphere.

  

  An “imbalance” in the energy budget of the Earth-atmosphere system is Radiative Forcing (RF, W/ m2), which is measured at the tropopause. RF is a simple method to quantitatively assess and compare the natural and anthropogenic causes of the climate change. The GHG’s absorb the infrared (thermal) radiations emitted by the earth into the space (causing a rise in temperature) and this forms the basis of RF measurements. Positive RF (mostly due to GHG’s with longer life spans, aerosols, albedo’s) indicates warming of the Earth’s surface and lower atmosphere, while negative RF has a reversal effect.

The table below illustrates the extent of RF caused by anthropogenic (green) and natural (red) agents (For a detailed representation of RF see: Table 2.12 in the following link: http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdf)

RF agents	RF (W/m²)
Carbon dioxide	+1.66
Methane	+0.48
Nitrous oxide	+0.16
Water vapour	+0.07
Total direct aerosols	-0.50 [±0.40]
Cloud albedo effect	-0.70
Surface albedo(landuse)	-0.20
Surface albedo BC aerosol on snow	+0.10[±0.10]
Solar irradiance	+0.12
Volcanic aerosols	Negligible

It is evident from the table that the net anthropogenic RF surpasses the RF of natural processes. Also the increase in the concentrations of greenhouse gases will reduce the efficiency of radiation from the Earth’s surface to the space. This enhances the greenhouse effect (an effect that has been operating in the Earth’s atmosphere for billions of years due to the presence of naturally occurring greenhouse gases and natural agents), thus causing global warming. 

 I feel that we have both history and science as guides, so why not make conscious efforts?

Thank you for reading. 

 

P.S: In my blogs I will be focusing on carbon dioxide (the chemistry behind why it is considered the most potent GHG, the sector based emissions with UK as a case study and then will talk about the different strategies that are and can be implemented to reduce sector specific emissions). I will also blog about a few interesting reports/news (current issues of climate change may not be linked with my blog topics, but when we talk about the environment we need a holistic approach and understanding of the various aspects) from India and UK and some interesting facts about other GHG's.