June 7, 2018

Greenhouse Gases

What is Greenhouse Gases and Its Impact on Our Environment.

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℃.

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Main Causes

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)
CO2 1 100
Methane ( CH4 ) 25 12
Nitrous Oxide (N2O) 298 114
Chlorofluorocarbon-12 (CCl2F2) 10900 100
Hydrofluorocarbon-23 (CHF3) 14800 270
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
CCl2F2 Refrigerants 0 0.527
CHF3 Refrigerants 0 0.024
SF6 Electricity transmission 0 0.0073
NF3 Semiconductor manufacturing 0 0.00086

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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