The greenhouse effect mechanism By S.M. Enzler MSc
But what exactly is the greenhouse effect? This page explains the mechanism.
Greenhouse effect - the mechanism
The sun radiates solar energy on earth. The larger part of this energy (45%) is radiated back into space. Greenhouse gases in the atmosphere (table 1) contribute to global warming by adsorption and reflection of atmospheric and solar energy. This natural phenomenon is what we call the greenhouse effect. It is agreed that the greenhouse effect is correlated with global temperature change. If greenhouse gases would not exist earthly temperatures would be below –18 oC.
Table 1: natural and anthropogenic greenhouse gases
After the industrial revolution of the 1700’s the greenhouse effect was enhanced by greenhouse gas emissions of anthropogenic nature (table 1). The main source of anthropogenic greenhouse gas emissions is fossil fuel combustion. The contribution of greenhouse gases to the greenhouse effect varies (figure 2).
Non-governmental organizations (NGO’s) such as the IPCC (Intergovernmental Panel on Climate Change) are attempting to predict and project the severity and consequences of global climate change caused by the greenhouse effect. The IPCC expects that annual greenhouse gas emissions will double in the next 50-100 years. This results in a cascade of environmental effects.
Ironically, an increase in greenhouse gases has been predicted to cause a cooling of the stratosphere. This phenomenon would occur because most thermal infrared is absorbed at low altitudes, and little is left over to warm the stratosphere. Additionally, at stratospheric temperatures CO2 emits more thermal infrared to space than it absorbs.