Climate Science Basics
Water vapor, or H2O is the gas form of water and is the most predominant greenhouse gas on
Earth. Similar to other Greenhouse Gases, it heats the Earth's surface through absorbing and reemitting
infrared radiation. But contrarily to CO2, which is often assumed to be its equivalent, the concentration
of the water vapor is not controlled by human activity but by natural changes in temperature. Water
vapor accounts for about two thirds of Greenhouse warming while CO2 only accounts for about one
fourth. Water vapor is controlled mainly by temperature; if the temperature is cooler, its causes
condensation and the water vapor will be dispensed in the form of rain or snow. But the warmer the
temperature, the more vapor is contained and controlled in the air. It is known as a Greenhouse Gas
amplifier, especially in combination with CO2 emissions. Scientists have uncovered that in the past 40
or so years, there has been a 4% increase in water vapor in the atmosphere, contributing greatly to the
warming of the planet.
Water vapor is one of the most prevalent Greenhouse Gases but it does not work alone and
requires other atmospheric activity to become the amplifier that it is. The atmosphere can only hold
more water vapor if the temperature rises, and for this temperature increase to occur, other gases such
as CO2 must be emitted into the atmosphere. The process in emphasized in the video when it is stated
that “...even though water vapor is not supplied to the atmosphere by human activity, it is an important
– and amplifying – greenhouse gas.” This shows that the vapor does not solely increase global
temperatures but is important to recognize in that it amplifies already increasing global climate.
As mentioned before, water vapor cannot by itself increase the temperature of the atmosphere.
CO2 is emitted mainly by man-made products, resources, and activities such a cement and steel
factories, consumer goods, residential and commercial electricity production, deforestation, and
transportation by/of cars and goods. These emissions increase the temperature of the atmosphere and
allow for a larger portion of water vapor to be retained. The more heat the atmosphere holds, the more
water vapor can be retained. But the vapor can only be held for so long before it is released back down
in the form of rain or snow. The amount of vapor changes from region to region. For example in humid
areas, near the equator, there is little room for water vapor to be put into the atmosphere and cause a
change in temperature, because it is already so densely packed. But in desert or arctic areas, it is very
dry and there is barely any water vapor in the atmosphere. In these areas there is much room for water
vapor to be retained in the atmosphere and cause a greater change in temperature. Though water vapor
is a Greenhouse Gas and occurs naturally in the atmosphere, the emissions of fossil fuels cause the
process of CO2 and the presentation of more water vapor, resulting in a significant effect on the heating
of the earth.