What is It?
Greenhouse gas (or GHG for short) is any gas that trap heat in the atmosphere. Its main effect is to make the planet grow warmer than it should be, were they not present. Greenhouse gases allow shortwave radiation such as sunlight to pass through the atmosphere freely, some of this energy passes back to space. This energy in turn, will be intercepted by the greenhouse gases in the atmosphere. These gases then absorb some of the escaping heat, and re-emit it towards the Earth, increasing its temperature altogether. It should be noted that greenhouse gases has its use, and available in some planets and moons in our solar system. Without their existence, our planet’s surface temperature will be just about 0℉ or -18℃.
Human has been the primary benefactor and producer of greenhouse gases since industrial revolution. Our fossil fuel combustion, deforestation, cement production, fertilizer application, agriculture, refrigerants, and electricity transmission / consumption are the primary factors. There are natural cause / source for GHG as well, but none contributes to the sharp 40% increase in the GHG concentration in the atmosphere since 1750, or 30% increase since 1955
Types of GHG
The Kyoto Protocol covers six GHG, of these, three are the primary concerns since they really are closely related to human activities, and their number does increase significantly because of us.
Global Warming Potential (GWP) and Atmospheric Lifetime for Major GHG 1
|GHG Type||GWP (Under 100-year horizon)||Atmospheric Lifetime (in years)|
|Methane ( CH4 )||25||12|
|Nitrous Oxide (N2O)||298||114|
|Sulfur Hexafluoride (SF6)||22800||3200|
|Nitrogen Trifluoride (NF3)||17200||740|
Sources and Concentrations of Major GHG 2
|GHG Type||Sources||Pre-Industrial concentration(ppb)||2011 concentration (ppb)|
|CO2||Fossil fuel combustion, deforestation, cement production||278000||390000|
|CH4||Fossil fuel production, Agriculture, Landfills||722||1803|
|N2O||Fertilizer application, Industrial processes, Fossil fuel and biomass combustion||271||324|
It should be noted that, water vapor is the most abundant greenhouse gas, but until proven otherwise, most scientists believe that water vapor produced directly by human activity contributes very little to the amount of water vapor in the atmosphere3.
By: Vincent Didiek Wiet Aryanto
Image taken from climatecentral.org