The document analyzes commercial aviation emissions and their effects on global temperatures. It is hypothesized that the projected increase in air travel will significantly increase positive radiative forcing from aviation emissions by 2050. Various emissions from fuel combustion, including CO2, NOx, SOx, water vapor, and soot, contribute to atmospheric warming. The growth of the aviation industry is expected to increase its share of total anthropogenic greenhouse gas emissions and radiative forcing if left unregulated.

1. Commercial Aviation Emissions and
Global Surface Temperatures
by
Jerome Lawrence
McNair Scholars Program
Embry-Riddle Aeronautical University

2. Purpose
The purpose of this research is to analyze the
amounts and effects of various
emissions from commercial aviation,
determine which gases contribute to
warming or cooling the atmosphere,
and estimate the average net radiative forcing (W/m2)
forecast for 2050.

3. Introduction
• Aviation: Very important role in the diversity and
prosperity of a country’s economy
• Presently: Air transport industry provides 28 million direct,
indirect and induced jobs worldwide
• Compared with total passenger kilometers flown in 1995,
an estimated increase of between 450% to 820% by 2050
• This growth will result in 14 billion to 23 billion passenger
kilometers flown annually by mid-century

4. Radiative Forcing
• Radiative forcing (RF) is a concept used for
quantitative comparisons of the strength of different
human and natural agents in causing climate change.
• Each agent has a different RF value.
• CO2 concentrations in 2005 had an RF of 1.66 [±0.17]
Wm-2: a 20% increase from 1995.

5. Components of the Climate Change Process
(IPCC, 2007)

6. Hypothesis
It is hypothesized that
the projected increase in air travel (pass. km)
will significantly increase the
positive radiative forcing (W/m2) from
commercial aviation emissions

7. Combustion Process
• CO2, NOx, SOx, H2O and
soot are all by products
of combustion
• For every gallon of
fuel burned,
21 lbs of CO2 is emitted
• Reducing fuel use
reduces the amount of
CO2 emitted
(GAO, 2009)

8. Air Quality and Aircraft Emissions
Volatile Organic Compounds
•VOCs: Umbrella term for numerous compounds that
become a gas at normal pressures and temperatures
•Extended exposure to some VOCs results in:
eye and respiratory tract irritation,
visual problems, headaches, dizziness,
and memory impairment

9. Air Quality and Aircraft Emissions
Unburned hydrocarbons
•During the combustion process, some of these
hydrocarbons are not burned completely or not burned
at all and are referred to as Unburned Hydrocarbons
•The top of nitrogen oxides and VOCs are
• 1.chemical factories
2. oil refineries
3.power stations
4.airports

10. The • As the sun’s energy traverses the
Greenhouse atmosphere it does not change the
Effect temperature of the atmosphere,
but it changes the temperature of the
land.
• Earth then reradiates a longer
wave of energy that falls in the
thermal infrared band of
wavelengths of the
electromagnetic spectrum.
• These wavelengths are easily
absorbed by greenhouse gases,
such as carbon dioxide, water
vapor, methane, and ozone

11. Air Quality and Aircraft Emissions
Nitrogen oxides
•Nitrogen oxides (NOx) include nitrogen dioxide (NO2), nitric
oxide (NO), and nitrous oxide (N2O).
•Estimates for specific engine-airframe combinations range
from 6 to 40g of NOx per kilogram of fuel burned
•The World Wildlife Federation estimated that NOx emitted
from aircraft above 10,000 feet have up to 50 times the
warming effect of NOx emitted at lower levels.

12. Air Quality and Aircraft Emissions
Particulate matter
•Particulate matter is a subset of the larger group
known as aerosols
•Many particulates, such as soot, serve as condensation
nuclei for water vapor in the atmosphere and tend to
form more high cirrus clouds than would otherwise be
present.

13. Air Quality
Carbon dioxide
and Aircraft •Preindustrial levels of CO2 were 280
Emissions ppm and the global average for 2011
was 392 ppm.
•Nearly 20% of the greenhouse gas
emissions worldwide are from
transportation.
•The CO2 emitted by air transport is at
least 0.23 billion tonnes of carbon
dioxide (GtC) per year.
• By 2050, aviation is expected to add
1.45 GtC to the atmosphere annually.

14. Air Quality and Aircraft Emissions
• The radiative forcing of CO2 is positive, that is, it
contributes to the warming of the earth.
• In 1992, aviation contributed 2.5% of the total
anthropogenic greenhouse gas emissions.
That amount has increased to over 3.5%
• CO2 is a potent greenhouse gas partly because of its
residence time which is approximately 100 years.

15. Air Quality and Aircraft Emissions
Contrails
•Contrails, or condensation trails, which are formed
from water vapor emitted from aircraft that freezes
into clouds at high altitudes,
also affect global temperatures
•.
(Eden, n.d)

16. Methane
• The atmospheric concentration of methane has exceeded
the natural range of the last 650,000 years.
• In 2005, methane was 319 ppb in comparison to 270 ppb
for many centuries prior to industrial times.
• It is estimated that methane produces about one-third
the amount of global warming of carbon dioxide.

17. • Global radiative forcing (RF) estimates and ranges
for anthropogenic carbon dioxide, methane (CH4),
nitrous oxide (N2O), contrails
and other important agents
(IPCC, 2007)

18. X-axis shows Time: 10,000 YBP to Present
2nd Y-axis: Radiative Forcing
• Carbon Dioxide (CO2)
• Methane (CH4)
• Nitrous Oxide (N2O)
(IPCC, 2007)

19. Changes in Global Temperatures,
Sea Level, and Snow Cover: 1850-2005
• As GHGs prevent some
of the heat reradiated
by Earth from leaving
the atmosphere,
global average
temperatures rise,
and snow cover declines
• Excessive CO2 and other
GHGs, therefore, have a
domino effect on the
environment

20. Sources of CO2
(GAO, 2009)

21. Relative Warming:
GHGs from Aviation Emissions
(GAO, 2009)

22. Growth in Aviation:
1978-2008
(GAO, 2009)

23. Reducing Emissions
• Past measures of reducing emissions from aircraft
were not extensive because adequate knowledge
about climate change was not widespread
• Catalytic converters were used to help reduce the
amount of hydrocarbons and CO2 added to the
atmosphere from automobiles
• U.S. EPA: fuel volatility limits were set
for all forms of transportation

24. Reducing Emissions
• The amount of GHG emission caused by aviation
could increase from 3.5% at present to a high of
15% by the year 2050
• CO2 emissions from aviation will range from
843-5,317 million tons per year by the year 2050,
a significant increase from 514 million tons in 1992
• Currently there are no laws on emissions at high
altitudes partly because there is no strong lobby to
reduce those emissions

25. Reducing Emissions
• NextGen would reduce aircraft emissions by 10-15%
by the year 2025 by using alternate fuels,
newer equipment and enhanced operational procedures
• If the industry continues to grow at its present rate
there would be an estimated 3% increase in emissions
for every 5% increase in traffic

26. Reducing Emissions
• The IPCC has forecast that by the year 2050,
fuels would be 40-50% more efficient
and there will be a decrease of NOx emissions
of 30-50% per aircraft
• General electrics developed the GEnx engine which is
designed to operate on less fuel and designed to last
longer than engines of today

27. Conclusions
• An increase in sea level is likely, longer and more
intense natural events will occur.
• Sulfates, PM, UHCs, contrails, cirrus, clouds, and
GHGs all contribute to atmospheric warming.
• The alternate hypothesis is accepted:
HA: The projected increase in air travel (pass. km) will
significantly increase positive radiative forcing
(W/m2) from commercial aviation emissions.

28. Recommendations
• The development of international laws
for regulating emissions
• The EPA could implement more stringent laws and
regulations to reduce emissions
• The average operating cost for a Boeing 737-400 is
$2,865.00 per hour. If alternative fuel sources are
used this cost will be reduced by 10%
• Emissions trading
• Blended Wing Body (BWB) aircraft is another type of
design which is still in development.

29. • Historically and currently,
the fossil fuel industry is the only industry that has not
had to pay for dumping its waste
(CO2 into the air)
Is it time
for a change?

30. Questions