Sustainable Engineering

Climate change means alterations in the composition of the global atmosphere. These changes alter natural climate variability and are observed over comparable time periods of the world. Also, these changes are directly or indirectly attributed to human activity.

Greenhouse gases are to blame. Why? Well, they influence the earth’s temperature balance by absorbing and emitting radiation at specific wavelengths. This occurs within the spectrum of infrared radiation emitted by the earth’s surface, the atmosphere, and the clouds.

The Greenhouse effect

Sunlight provides solar energy, which the earth’s surface usually absorbs. This absorption causes the earth to become warm and emit infrared radiation. Solar energy is also usually reflected back into the atmosphere by the water/ oceanic part of the earth’s surface. Greenhouse gases trap this radiation in the atmosphere, warming up the atmosphere, thus creating the “Greenhouse effect“.

Greenhouse gases and their Global Warming Potential (GWP)

Water Vapour (H₂O), Carbon dioxide (CO₂), Nitrous Oxide (NO₂), Methane (CH₄), and Ozone (O₃) are the primary GHG gases. Sulphur Hexaflouride (SF₆), hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) are also contributors majorly attributed to human activity.

The Global Warming Potential (GWP) was developed to measure the global warming impact of the gases above. It measures the absorption of emissions of one ton of a gas over a given period. This is measured relative to the emission of one ton of carbon dioxide (CO₂). The larger the GWP, the more the gas warms the earth (compared to CO₂) over a given time period. The time period is usually 100 years.

According to the IPCC sixth assessment report, Nitrous Oxide (NO₂) and Methane (CH₄) have a stronger impact on the atmosphere. Their impact is significant despite their small atmospheric concentrations. The report produced a graph below that illustrates the comparisons of with Nitrous Oxide being more severe;