Impact of Greenhouse Gases on Climate Change and Potential Runaway Greenhouse Effect
The Earth’s land masses, oceans, and even the polar ice caps are warmer than surrounding outer space. The atmosphere carries away that heat into outer space. Greenhouse gasses (GHGs) typically absorb radiation emitted in the infrared portion of the electromagnetic spectrum by warm objects. The presence of GHGs slows down the rate of heat transfer from the Earth’s surface into outer space. When this happens, heat from solar illumination and the decay of radioactive elements within the Earth builds up and raises the temperature of the Earth’s surface and the lower layers of its atmosphere.
A moderate level of greenhouse gas helps to maintain a temperate climate on the Earth, so that life can thrive. However, human society of Earth is now facing too much of a good thing. The build-up of heat on the Earth’s surface is beneficial (even necessary) to life on Earth up to a point.Beyond that point, excess heat build-up becomes destructive to the Earth’s ecosystem. A run-away greenhouse effect could be triggered, such has already occured on the Earth's nearest neighbor, Venus.
The level of greenhouse gasses have been steadily escalating in the atmosphere over the past century, so that now excessive heat is being trapped in the Earth's atmosphere. This excessive heat is causing croplands to dry out, the polar caps to melt and other environmental stress. There is now serious concern that excessive heat build-up might result causing serious droughts and severe ecosystem disruption that would threaten human and other life on Earth.
As the oceans heat up, evaporation increases, and even more H2O goes into the atmosphere. Sinse H2O is itself a greenhouse gas, it further traps hear, triggering further evaporation, resulting an out-of-control cycle. Such a cycle could turn the Earth into a Venus-like planet with surface temperatures of 900° F and rain comprising sulfuric acid. Little of what we call life on Earth could surface such conditions.
There is some debate whether these rising levels of greenhouse gasses are caused by humans or nature. Yet this debate is really besides the point. That is like deciding whether to put out a house fire by asking if the fire was caused by lightning or matches. The real question is can we as intelligent humans modify our behavior to slow down and stop the escalating greenhouse gas level and resultant heating trend? Most scientists feel that if human society can cut down its emissions of greenhouse gasses, this trend can be immediately slowed down and eventually stopped.
Therefore it is important to raise awareness of how much particular human activities are contributing to excessive greenhouse gas emissions, frequently called carbon emissions. If people are aware of how their activities, such as the products they purchase, impact carbon emissions, then they can help reduce those emissions by making informed purchasing and lifestyle choices.