Causes of Climate Change - Climate Resilient Agriculture for Ensuring Food Security - page 21

Fig. 2.3

Carbon dioxide emissions from industries

It increases as the earth's atmosphere warms, but
so does the possibility of clouds and precipitation,
making these some of the most important feed-
back mechanisms to the greenhouse effect. Much
of the heat that escapes from the oceans is in the
form of water vapor, the most abundant green-
house gas on earth. Yet, water vapor also contrib-
utes to the formation of clouds, which shade the
surface and have a net cooling effect.

The industrial activities that our modern civi-
lization depends upon have raised atmospheric
CO 2 levels from preindustrial value of 280 parts
per million to 389 parts per million in 2010.
Without mitigation measures, the concentration
of CO 2 in the atmosphere is predicted to rise to at
least 650 ppm and up to 1,200 ppm by 2100
(IPCC 2001 ), which is expected to increase aver-
age global temperature by 1-6 °C (Fig. 2.3 ).
When we mine coal and extract oil from the
earth's crust and then burn these fossil fuels for
transportation, heating, cooking, electricity, and
manufacturing, we are effectively moving car-
bon more rapidly into the atmosphere than is
being removed naturally through the sedimenta-
tion of carbon, ultimately causing atmospheric
carbon dioxide concentrations to increase.
Burning fossil fuels, such as coal, oil, and natu-
ral gas, to generate energy has the greatest
impact on the atmosphere than any other single
human activity. Globally, power generation is
responsible for about 23 billion tons of CO 2
emissions per year - in excess of 700 ton every
second. Coal is especially damaging to our
atmosphere, releasing 70 % more carbon diox-
ide than natural gas for every unit of energy
produced.
Forests help to protect the planet by absorb-
ing massive amounts of carbon dioxide (CO 2 ),
the most abundant type of pollution that causes
climate change. Unfortunately, forests are cur-
rently being destroyed or damaged at an alarm-
ing rate. By clearing forests to support

2.3.2 Carbon Dioxide (CO 2 )

Carbon dioxide is undoubtedly the most
important greenhouse gas in the atmosphere. A
minor but very important component of the atmo-
sphere, CO 2 is released through natural processes
such as respiration and volcano eruptions and
through human activities such as deforestation,
land-use changes, land clearing, agriculture,
burning fossil fuels, and other activities. The
main sources of CO 2 are decay of organic matter,
forest fi res, eruption of volcanoes, burning of fos-
sil fuels, deforestation, and land-use change,
whereas plants, oceans, and atmospheric reac-
tions are the major sinks. Though agricultural
soil is a small contributor of carbon dioxide, fac-
tors such as soil texture, temperature, moisture,
pH, and available C and N contents infl uence
CO 2 emission from soil. Humans have increased
atmospheric CO 2 concentration by a third since
the industrial revolution began. This is the most
important long-lived “forcing” of climate change.