| Temperatures on Earth are determined
by the natural greenhouse effect - part of the solar radiation
reaching the Earth's surface is absorbed, and part is reflected to
the atmosphere as infrared radiation. Water vapour and greenhouse
effect gases (carbon dioxide, methane, sulphur dioxide, ozone, and
others) do not hinder the path of solar radiation through the
atmosphere, but they absorb the reflected infrared radiation. The
mean temperature on the surface would be about -18°C without this
absorption, but is about +14°C with the absorption.
An increase in the atmospheric concentration of greenhouse
effect gases causes increased absorption of infrared radiation,
raising the temperatures. This causes an additional greenhouse
effect.
Anthropogenic gases which disrupt the heat exchange equilibrium
include: carbon dioxide (CO2), methane (CH4), nitrogen oxide
(N2O), hydrofluorocarbons (HFC), perfluorocarbons (PFC), and
sulphur hexafluoride (SF6). These gases create a layer around
Earth which does not allow heat to dissipate to the cosmos, and
causes various changes: increase in global temperatures, raising
sea level, changes in species composition, and others.
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