CONTRIBUTION OF AERO ENGINES IN GLOBAL WARMING
CONTENTS
Page No
Introduction 3
What is Global Warming? 3
Aviation’s Contribution 4
Global Emissions 4
Environmental Effect 6
Mechanism 7
Aircraft Technology and Design 8
Alternate Sources 9
Conclusion 10
Recommendations 11
Web References 12
The Term Paper on Sociological Perspective On Global Warming And Health Problems Associated With It
... -greenhouse-sense.h tml [13 April 2008]. Thompson, P. 1996.Effects of Global Warming. Times Square. Available from: http://www.geocities.com/timessquare/1848/global.h tml [13 April 2008 ... from: http://environment.guardian.co.uk/climatechange/st ory/0,,2025726,00.html [13 April 2008]. Abstract: This paper discusses Global warming and its effects on peoples health from sociological perspective. ...
CONTRIBUTION OF AERO ENGINES IN GLOBAL WARMING
Introduction
1. There is broad international agreement that climate change is an issue of global significance and the world must act to tackle the problem. Aviation has been the target of much attention in this sphere recently. While the air transport industry does contribute to greenhouse gas emissions, it is but one of the causes. Aircraft engines produce emissions that are similar to other emissions resulting from fossil fuel combustion. However, aircraft emissions are unusual in that a significant proportion is emitted at altitude. These emissions give rise to important environmental concerns regarding their global impact and their effect on local air quality at ground level.Aviation is a relatively small contributor to climate change. Aviation is responsible for 2% of manmade CO2 emissions worldwide.This is according to The United Nations Intergovernmental Panel on Climate Change (IPCC).However, with predicted industry growth, that amount is set to slowly rise.This is small compared to the principal sources of CO2 emissions, such as power generation and road transport, but this does not mean that the aviation industry is ignoring its commitment to combating climate change proactively.
What Is Global Warming?
2. In its most commonly used sense, “global warming” refers to the gradual warming of global-average temperatures due to the slowly increasing concentrations of man-made atmospheric greenhouse gases, primarily carbon dioxide.But global warming can alternatively refer to simply the observation of warming,without implying the cause(s) of that warming.
3. The burning of fossil fuels, mainly petroleum and coal, produces carbon dioxide as one of the by-products. As of 2010, the concentration of carbon dioxide is about 50% higher than it was before the start of the industrial revolution in the late 1800’s. The potential warming effect of the extra CO2 is through its ability to absorb and emit infrared radiation, which is the type of radiation the Earth continually loses to outer space in response to heating by sunlight. This makes carbon dioxide a greenhouse gas, albeit a weaker one in the atmosphere than water vapour.
The Essay on Ways to Reduce Global Warming
Global Warming refers to the gradual increase in the Earth’s temperature as a result of the growing concentration of human induced green house gases which are carbon dioxide, chlorofluorocarbons and hydro fluorocarbon in our atmosphere. Global warming can be caused by the use of fossil fuels, and industrial or agricultural processes. Man-made emissions are adding to the amount of carbon dioxide ...
4. The net effect of greehouse gases on is to keep the lower layers of the atmosphere warmer that they otherwise would be without those gases. Therefore, it has seemed reasonable to assume that an increase in greenhouse gases would lead to warming.
Aviation’s Contribution
5. Air travel is one of the world’s fastest growing source of greenhouse gases (computing an IT is another) like carbon dioxide, which cause climate change. Globally the world’s 16,000 commercial jet aircraft generate more than 700 million tonnes of carbon dioxide (CO2), the world’s major greenhouse gas, per year. Indeed aviation generates nearly as much CO2 annually as that from all human activities in Africa. One person flying a return trip between London and New York generates between 1.5 and 2 tonnes of CO2.
6. CO2 emissions are the principal cause of global warming and the United Nation’s Intergovernmental Panel on Climate Change (IPCC), the foremost global authority on the issue, has confirmed that aviation contributes 2% of the world’s CO2 emissions.Despite growth in passenger numbers at an average of 5% each year, aviation has managed to decouple its emissions growth to around 3%, or some 20 million tonnes annually.As aviation grows to meet increasing demand, the IPCC forecasts that its share of global manmade CO2 emissions will increase to around 3% in 2050.
Global Emissions
7. It’s not easy to estimate the impact of aviation on our climate today and even more difficult to determine what effect it will have in the future. Up until recently, the aviation industry had little impact on the climate system but, as it is an extremely fast growing energy consumer, it is assumed that air transport will be an important factor governing climate in the future.
The Essay on Causes Of Climate Change 2
Causes of Climate Change Climate change is a long-term shift in weather conditions identified by changes in temperature, precipitation, winds, and other indicators. Climate change can involve both changes in average conditions and changes in variability, including, for example, extreme events. The earth's climate is naturally variable on all time scales. However, its long-term state and average ...
a) Aviation Emissions
(i) Like a number of other human activities (such as driving cars and using fossil fuels for electricity generation), aviation has an impact on climate change, mainly through the emissions from aircraft as they fly. It’s not easy to estimate the impact of aviation on our climate today and even more difficult to determine what effect it will have in the future. Up until recently, the aviation industry had little impact on the climate system but, as it is an extremely fast growing energy consumer, it is assumed that air transport will be an important factor governing climate in the future.
(ii) There is some disagreement over the extent of the aviation industry’s contribution to climate change. There seems to be a good understanding of CO2 emissions, which contribute directly to the greenhouse effect, along with water vapour. However the impacts of other by-products such as nitrogen oxides (NOx) and the contrails formed by aircraft under certain atmospheric conditions, are less certain. The primary gas emitted by jet aircraft engines is carbon dioxide, which can survive in the atmosphere up to 100 years. Carbon dioxide, combined with other exhaust gases and particulates emitted from jet engines, could have two to four times as great an impact on the atmosphere as carbon dioxide emissions alone.
b) Local Emissions
(i) This is according to The United Nations Intergovernmental Panel on Climate Change (IPCC). The October 2006 report by Sir Nicholas Stern states that the largest contributor to human-induced CO2 is power generation (24%), mostly produced in coal and gas fired stations. Next is land use change at 18%, then agriculture, industry and transport at 14% each (aviation is part of transport).
Buildings (8%), other energy related activities (5%) and waste (3%) make up the rest.
(ii) Of all the different forms of transport, cars produce by far the most CO2 emissions.According to the recently-published Stern Review (The Economics of Climate Change),cars are responsible for 76% of all CO2 emissions from the transport sector with ships and aircraft 10% and 12% respectively.
(iii) CO2 is not the only emission from aviation, however. The exhaust from aircraft engines is made up of: 7% to 8% CO2 and water vapour; 0.5% nitrogen oxides, unburned hydrocarbons, carbon monoxide and sulphur oxides; traces of hydroxyl family and nitrogen compounds and small amounts of soot particles (although the industry has managed to more or less eliminate soot emissions over the past few decades).
The Essay on Effect Of Climate Change
Along with its anxiety-inducing effects, climate change also offers an interesting opportunity to consider fascinating, interconnected processes on Earth. The smallest to the largest components of the planet – from bacteria to volcanoes – all somehow feel the effects of a changing climate. Here are six of the most unexpected ways climate change impacts Earth Desert bacteria dies Desert soil may ...
Between 91.5% and 92.5% of aircraft engine exhaust is normal atmospheric oxygen and nitrogen.
Human Induced CO2 Emissions
————————————————-
International Energy Agency 2002 Data
Electricity generation | 35% |
Road transport | 18% |
Industry | 18% |
Other sectors | 10% |
Residential | 8% |
Energy | 5% |
Other transport | 4% |
Aviation | 2% |
The Intergovernmental Panel on Climate Change (IPCC) also produced a figure of 2% of CO2 emissions, but said that the figure for all greenhouse gas emissions from aviation was around 3% of total human emissions. The IPCC study suggests that figure will increase to around 5% of the world’s total emissions in 2050. |
Environmental Effect
8. Aeroplanes emit gases and particles directly into the upper troposphere and the lower stratosphere. They alter the concentration of atmospheric greenhouse gases, including carbon dioxide (CO2), ozone (O3) and methane (CH4).
They also trigger the formation of condensation trails (contrails) and may increase cirrus cloudiness. All these factors contribute to climate change.
Mechanism
9. Subsonic aircraft-in-flight contribute to climate change in four ways:
a) Carbon Dioxide (CO2).
CO2 emissions from aircraft-in-flight are the most significant and best understood[10] element of aviation’s total contribution to climate change. The level and effects of CO2 emissions are currently believed to be broadly the same regardless of altitude (i.e. they have the same atmospheric effects as ground based emissions).
In 1992, emissions of CO2 from aircraft were estimated at around 2% of all such anthropogenic emissions, and that year the atmospheric concentration of CO2 attributable to aviation was around 1% of the total anthropogenic increase since the industrial revolution, having accumulated primarily over just the last 50 years.
The Essay on The Effects Of Carbon Monoxide (CO) On The Human Body
Carbon monoxide is a tasteless, odorless, colorless, highly toxic, and flammable gas. Its chemical formula is CO. Carbon monoxide is mostly formed from the incomplete combustion of carbon and/or molecules that contain carbon. Carbon monoxide is usually inhaled into the body when people smoke cigarettes or any other substances. When breathed into the human body, carbon monoxide alters the ...
b) Oxides of Nitrogen (NOx)
(i) At the high altitudes flown by large jet airliners around the tropopause, emissions of NOx are particularly effective in forming ozone (O3) in the upper troposphere. High altitude
(8-13km) NOx emissions result in greater concentrations of O3 than surface NOx emissions, and these in turn have a greater global warming effect. The effect of O3 concentrations are regional and local (as opposed to CO2 emissions, which are global).
(ii) NOx emissions also reduce ambient levels of methane, another greenhouse gas, resulting in a climate cooling effect. But this effect does not offset the O3 forming effect of NOx emissions. It is now believed that aircraft sulfur and water emissions in the stratosphere tend to deplete O3, partially offsetting the NOx-induced O3 increases. These effects have not been quantified.[11] This problem does not apply to aircraft that fly lower in the troposphere, such as light aircraft or many commuter aircraft.
c) Water Vapour (H2O) and Cirrus Cloud Formation
(i) One of the products of burning hydrocarbons in oxygen is water vapour, a greenhouse gas. Water vapour produced by aircraft engines at high altitude, under certain atmospheric conditions, condenses into droplets to form Condensation trails, or contrails.
Contrails are visible line clouds that form in cold, humid atmospheres and are thought to have a global warming effect (though one less significant than either CO2 emissions or NOx induced effects) SPM-2. Contrails are extremely rare from lower-altitude aircraft, or from propeller-driven aircraft or rotorcraft.
(ii) Cirrus clouds have been observed to develop after the persistent formation of contrails and have been found to have a global warming effect over-and-above that of contrail formation alone. There is a degree of scientific uncertainty about the contribution of contrail and cirrus cloud formation to global warming and attempts to estimate aviation’s overall climate change contribution do not tend to include its effects on cirrus cloud enhancement.
d) Particulates. Least significant is the release of soot and sulphate particles. Soot absorbs heat and has a warming effect; sulphate particles reflect radiation and have a small cooling effect. In addition, they can influence the formation and properties of clouds. All aircraft powered by combustion will release some amount of soot.
The Term Paper on Global Warming: Causes, Effects and Possible Measures
Global warming is the term used to describe some of the drastic changes that are taking place in the earth’s climatic conditions. Over the recent years, the term global warming has been the subject of much debate and different people have come up with different views regarding this subject. While many people continue to hold to the view that global warming is a natural phenomenon that cannot be ...
Aircraft Technology and Design
10. Aircraft manufacturers are constantly redesigning and re-engineering aircraft, to incorporate advancements in technologies and designs. Manufacturers have developed lighter materials, more aerodynamic designs, and better engines so that the aircraft they produce are more efficient, reducing fuel burn and therefore emissions. Aircraft engines are becoming more and more efficient and are helping limit the impact of aviation on climate change. Continuing to improve efficiency is a key consideration for aircraft engine manufacturers.
a) Supersonic Air Transport. At higher altitudes, emissions of nitrogen oxides lead to decreases in the stratospheric ozone layer. This is one reason why supersonic passenger air transport has never really developed. Emissions into the stratosphere spread around the globe and we don’t know the likely consequences of this on the atmospheric system and the ozone layer. Concorde, which had her maiden flight in 1969 and flew at an altitude of 18 km in the stratosphere, was the only regularly used commercial supersonic passenger jet. It had its last flight in 2003.
b) Airbus A380. Although international aviation was excluded from the 1997 Kyoto Protocol, the International Civil Aviation Organization (ICAO) arranged a summit in 2007 to look at how manufacturers, airlines, airports, and governments can work together to reduce aviation’s carbon footprint. Boeing has created the next generation of aircraft from composite materials that weigh far less than their predecessors. The Boeing 787 Dreamliner is one such new development, with 50 percent of its structure made up of composite materials. Boeing estimates that the 787 will create 20 percent less carbon than the current aircraft operating on medium/long range routes. Airbus has promoted the development of aircraft that place greater emphasis on reducing their carbon footprint. The Airbus A380 Super Jumbo, while bigger than the jumbo jet, has a low fuel burn (12 percent lower than the jumbo jet) and is able to take more passengers, helping to reduce the number of aircraft required to fly on certain routes. The Airbus A380 is the first jet airliner to meet International Environmental Standard ISO 14001.
Alternate Sources
11. The anticipated gain in efficiency from technological and operational measures does not offset the overall emissions that are forecast to be generated by the expected growth in traffic. To achieve the sustainability of air transport, other strategies will be needed to compensate for the emissions growth not achieved through efficiency improvements and to build better planes and more efficient engines powered by non-carbon sources. Some potential building blocks already exist – solar power, hydrogen cells and biofuel.
a) Carbon Offsetting. Carbon offsetting is a voluntary way of combating climate change by funding sustainable projects all over the world. Although it is perhaps not a long-term solution, offsetting means paying a little more for your ticket to compensate for the CO2 resulting from your flight. The money helps to fund diverse projects around the world; for example, to replace non-renewable fuel, such as coal, with renewable forms of energy such as biomass or solar, or perhaps to support forest restoration, which helps absorb CO2 from the atmosphere. More and more airlines are offering passengers to opportunity to offset their carbon emissions. The main ones are British Airways, SAS Group and Cathay Pacific. On top of this many organisations are helping individuals and companies to offset their carbon emissions. Some of the main ones are The Carbon Neutral Company, and The Conservation Fund.
b) Alternate Fuels or Biofuels
(i) The industry is actively developing and testing potential alternative fuels for aviation. When blending biofuel made of crops or algae with traditional jet fuel, it is possible to substantially reduce CO2 emissions. One of the problems to be addressed is related to the temperature at which biofuels freeze, since aircraft operate at high altitudes where the outside temperature is very low.
(ii) However, industry continues to examine using alternative fuels in the future with major airlines such as South African Airways, Qatar Airways and Virgin all pushing forward alternative fuel projects and trials.
(iii) Hydrogen is being explored for application in the very near future in fuel cells for the auxiliary power units (APUs) that provide energy to aircraft standing at the gate. Hydrogen might become an option for aircraft engines from 2050, although significant design and
infrastructure changes would be required, in particular regarding the size of the tanks since hydrogen is lighter but far more voluminous than jet fuel.
12. Conclusion
a) Flying meets the need for global connections, and without it the global economy would suffer. In many cases, flying simply cannot be replaced by other modes of transport. In many parts of the world, road and rail infrastructure is grossly inadequate. Traffic demand is growing worldwide, not diminishing, including developing nations that are in great need of affordable passenger and cargo traffic to build their economies.
b) The IPCC estimates that aviation today is responsible for 2 percent of global CO2 emissions with a total climate change impact of 3 percent. These figures have remained largely unchanged over the last two decades, despite the growth of air traffic.
c) Fuel efficiency and fuel conservation strategies will continue to dominate airline fuel policy.
d) Kerosene will continue to be used in aircraft with a gradual shift to synthetic fuel driven by availability and price.
e) Hydrogen powered aircraft offer little benefit until there is a worldwide supply.
f) An increase in the number of supersonic aircraft could further damage the ozone layer as aircraft emissions of NOx deplete ozone concentrations at high altitudes, where these aircraft would typically fly.
g) Aircraft manufacturers are constantly redesigning and re-engineering aircraft, to incorporate advancements in technologies and designs.
h) Manufacturers have developed lighter materials, more aerodynamic designs, and better engines so that the aircraft they produce are more efficient, reducing fuel burn and therefore emissions.
i) Global Warming emissions will continue to be a serious problem.
Recommendations
13. There is scope to reduce the environmental impacts of aviation using technological means:
a) The right choice is not to fly less, but to continue to make sure that the air transport sector proactively and progressively addresses emissions, noise, and a range of community concerns in order to balance environmental commitment and growing capacity needs.
b) The environmental impacts of airport operations can be lessened through careful engineering and mitigation(e.g. recycling wastes, ensuring energy efficiency in buildings and locating infrastructure away from sensitive habitats).
c) The emissions of air pollutants and greenhouse gases can be reduced by improving the efficiency of engines.
d) Advances in telecommunications can reduce the need to travel. Tele- and video-conferencing are increasingly becoming a viable alternative to flying for many business travellers.
e) Facilitating development of standardized definitions, methodologies and processes to support the development of sustainable alternative fuels for aviation, taking into consideration the work that has been done so far in this area.
f) Actively explore the progressive introduction of alternative fuels to further reduce CO2 emissions.
Web References
14. The following are the web references:
a) May 2011
b) www.aci-na.org/austinroundup/…/e66f396d1b4e9958dab6131046a4d9ff, 27th May 2011
c) www.nytimes.com/2007/09/20/…/20iht-edbisi.1.7583290.html, 30th May 2011
d) what-when-how.com/global-warming/aviation-global-warming/,26th June 2011
e) www.brighthub.com › … › Environmental Science › Pollution, 23th June 2011
f) www.enviro.aero/Frequentlyaskedquestions.aspx, 30th May 2011
