GHG Emissions

Contents

1. Green House Gases (GHG)...............................................................................2

2. Recent Trends in U.S. Green House Gas Emissions and Sinks..........................5

3. Possible Measures at Individual Level to Reduce Global Warming................10

4. Conclusion......................................................................................................11

References:............................................................................................................12

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1. Green House Gases (GHG)The gases in the atmosphere that absorb radiation are known as "greenhouse gases"

(sometimes abbreviated as GHG) because they are largely responsible for the greenhouse

effect. The greenhouse effect, in turn, is one of the leading causes of global warming. The

most significant greenhouse gases are water vapor (H2O), carbon dioxide (CO2), methane

(CH4) and nitrous oxide (N2O), according to the Environmental Protection Agency (EPA).

While oxygen (O2) is the second most abundant gas in our atmosphere, O2 does not absorb

thermal infrared radiation.

While some say that global warming is a natural process and that there have always been

greenhouse gasses, the amount of gasses in the atmosphere has skyrocketed in recent

history. The Industrial Revolution had a big part to play in the amount of atmospheric CO2

being released. Before, CO2 fluctuated between about 180 ppm during ice ages and 280 ppm

during interglacial warm periods. Since the Industrial Revolution, though, the amount of

CO2 has dramatically increased to 100 times faster than the increase when the last ice age

ended, according to the National Oceanic and Atmospheric Administration (NOAA).

Fluorinated gases - that is, gases to which the element fluorine was added — including

hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride, are created during industrial

processes and are also considered greenhouse gases. Though they are present in very small

concentrations, they trap heat very effectively, making them high "global-warming

potential" (GWP) gases.

Chlorofluorocarbons (CFCs), once used as refrigerants and aerosol propellants until they

were phased out by international agreement, are also greenhouse gases.

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Three factors affect the degree to which any greenhouse gas will influence global warming:

Its abundance in the atmosphere

How long it stays in the atmosphere

Its global-warming potential

Carbon dioxide has a significant impact on global warming partly because of its abundance

in the atmosphere. According to the EPA, in 2012, U.S. greenhouse gas emissions totaled

6,526 million metric tons of carbon dioxide equivalents, which equaled 82 percent of all

human caused greenhouse gasses. Additionally, CO2 stays in the atmosphere for thousands

of years.

However, methane is about 21 times more efficient at absorbing radiation than CO2, giving

it a high GWP rating, even though it stays in the atmosphere only about 10 years, according

to the EPA.

Some greenhouse gases, like methane, are produced through agricultural practices including

livestock manure management. Others, like CO2, largely result from natural processes like

respiration and from the burning of fossil fuels like coal, oil and gas. The production of

electricity is the source of 70 percent of the United States' sulfur dioxide emissions, 13

percent of nitrogen oxide emissions, and 40 percent of carbon dioxide emissions, according

to the EPA.

The second cause of CO2 release is deforestation, according to research published by Duke

University. When trees are killed to produce goods or heat, they release the carbon that is

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normally stored for photosynthesis. This process releases nearly a billion tons of carbon into

the atmosphere per year, according to the 2010 Global Forest Resources Assessment.

Worldwide, the output of greenhouse gases is a source of grave concern: From the time the

Industrial Revolution began to the year 2009, atmospheric CO2 levels have increased almost

38 percent and methane levels have increased a whopping 148 percent, according to NASA,

and most of that increase has been in the past 50 years. Because of global warming, 2014

was the warmest year on record and 10 of the hottest years have all come after 1998.

If these trends continue, scientists, government officials and a growing number of citizens

fear that the worst effects of global warming — extreme weather, rising sea levels, plant and

animal extinctions, ocean acidification, major shifts in climate and unprecedented social

upheaval — will be inevitable. In answer to the problems caused by global warming by

greenhouse gasses, the government created a climate action plan in 2013.

Increasing emissions of greenhouse gases due to human activities worldwide have led to a

substantial increase in atmospheric concentrations of long-lived and other greenhouse gases.

Every country around the world emits greenhouse gases into the atmosphere, meaning the

root cause of climate change is truly global in scope. Some countries produce far more

greenhouse gases than others, and several factors—such as economic activity, population,

income level, land use, and climatic conditions—can influence a country’s emissions levels.

Tracking greenhouse gas emissions worldwide provides a global context for understanding

the United States’ and other nations’ roles in climate change.

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2. Recent Trends in U.S. Green House Gas Emissions and SinksAs per Inventory of U.S. Greenhouse Gas Emissions and Sinks April 2015 report, in 2013,

total U.S. greenhouse gas emissions were 6,673.0 MMT or million metric tons CO2

equivalent. Total U.S. emissions have increased by 5.9 percent from 1990 to 2013, and

emissions increased from 2012 to 2013 by 2.0 percent (127.9 MMT CO2 Eq.). The increase

from 2012 to 2013 was due to an increase in the carbon intensity of fuels consumed to

generate electricity due to an increase in coal consumption, with decreased natural gas

consumption.

Additionally, cold winter conditions lead to an increase in fuels for the residential and

commercial sectors for heating. In 2013 there also was an increase in industrial production

across multiple sectors resulting in increases in industrial sector emissions. Lastly,

transportation emissions increased as a result of a small increase in vehicle miles traveled

(VMT) and fuel use across on-road transportation modes. Since 1990, U.S. emissions have

increased at an average annual rate of 0.3 percent. Figure 2-1 through Figure 2-3 illustrate

the overall trend in total U.S. emissions by gas, annual changes, and absolute changes since

1990.

Figure 2-1: U.S Greenhouse Gas Emissions by Gas

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Source: Inventory of U.S. Greenhouse Gas Emissions and Sinks April 2015 report

Figure 2-2: Annual Percent Change in U.S. Greenhouse Gas Emissions

Source: Inventory of U.S. Greenhouse Gas Emissions and Sinks April 2015 report

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Figure 2-3: Cumulative Change in Annual U.S. Greenhouse Gas Emissions Relative to 1990

Source: Inventory of U.S. Greenhouse Gas Emissions and Sinks April 2015 report

Figure 2-4 illustrates the relative contribution of the direct greenhouse gases to total U.S.

emissions in 2013. The primary greenhouse gas emitted by human activities in the United

States was CO2, representing approximately 82.5 percent of total greenhouse gas emissions.

The largest source of CO2, and of overall greenhouse gas emissions, was fossil fuel

combustion. CH4 emissions, which have decreased by 14.6 percent since 1990, resulted

primarily from enteric fermentation associated with domestic livestock, natural gas systems,

and decomposition of wastes in landfills. Agricultural soil management, manure

management, mobile source fuel combustion and stationary fuel combustion were the major

sources of N2O emissions. Ozone depleting substance substitute emissions and emissions of

HFC-23 during the production of HCFC-22 were the primary contributors to aggregate HFC

emissions. PFC emissions resulted as a byproduct of primary aluminum production and

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from semiconductor manufacturing, while electrical transmission and distribution systems

accounted for most SF6 emissions.

Figure 2-4: 2013 Greenhouse Gas Emissions by Gas (Percentages based on MMT CO2

Eq.)

Source: Inventory of U.S. Greenhouse Gas Emissions and Sinks April 2015 report

Overall, from 1990 to 2013, total emissions of CO2 increased by 381.5 MMT CO2 Eq. (7.4

percent), while total emissions of CH4 decreased by 109.2 MMT CO2 Eq. (14.6 percent), and

total emissions of N2O increased 25.3 MMT CO2 Eq. (7.7 percent). During the same period,

aggregate weighted emissions of HFCs, PFCs, SF6, and NF3 rose by 74.3 MMT CO2 Eq.

(72.9 percent). Despite being emitted in smaller quantities relative to the other principal

greenhouse gases, emissions of HFCs, PFCs, SF6, and NF3 are significant because many of

them have extremely high GWPs and, in the cases of PFCs SF6, and NF3, long atmospheric

lifetimes. Conversely, U.S. greenhouse gas emissions were partly offset by Carbon

sequestration in managed forests, trees in urban areas, agricultural soils, and landfilled yard

trimmings. These were estimated to offset 13.2 percent of total emissions in 2013.

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As the largest contributor to U.S. greenhouse gas emissions, carbon dioxide (CO2) from

fossil fuel combustion has accounted for approximately 77 percent of global warming

potential (GWP) weighted emissions for the entire time series since 1990, from 75 percent

of total GWP-weighted emissions in 1990 to 77 percent in 2013. Emissions from this source

category grew by 8.8 percent (417.0 MMT CO2 Eq.) from 1990 to 2013 and were

responsible for most of the increase in national emissions during this period. From 2012 to

2013, these emissions increased by 2.6 percent (131.7 MMT CO2 Eq.). Historically, changes

in emissions from fossil fuel combustion have been the dominant factor affecting U.S.

emission trends.

Changes in CO2 emissions from fossil fuel combustion are influenced by many long-term

and short-term factors, including population and economic growth, energy price

fluctuations, technological changes, and seasonal temperatures. On an annual basis, the

overall consumption of fossil fuels in the United States fluctuates primarily in response to

changes in general economic conditions, energy prices, weather, and the availability of non-

fossil alternatives. For example, in a year with increased consumption of goods and services,

low fuel prices, severe summer and winter weather conditions, nuclear plant closures, and

lower precipitation feeding hydroelectric dams, there would likely be proportionally greater

fossil fuel consumption than in a year with poor economic performance, high fuel prices,

mild temperatures, and increased output from nuclear and hydroelectric plants.

In the longer-term, energy consumption patterns respond to changes that affect the scale of

consumption (e.g., population, number of cars, and size of houses), the efficiency with

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which energy is used in equipment (e.g., cars, power plants, steel mills, and light bulbs) and

behavioral choices (e.g., walking, bicycling, or telecommuting to work instead of driving).

Energy-related CO2 emissions also depend on the type of fuel or energy consumed and its

carbon (C) intensity. Producing a unit of heat or electricity using natural gas instead of coal,

for example, can reduce the CO2 emissions because of the lower C content of natural gas.

3. Possible Measures at Individual Level to Reduce Global WarmingGlobal warming is considered as real and growing threat for human beings and climate by

most of the scientists. Though the government is doing its own contribution, maximum

reduction in global warming can be achieved only when each individual participate in it.

Sure, as an individual, one can do many things in his/her home for reducing global warming.

In this connection first you need to focus the areas, which are the biggest source of global

warming. The first thing is definitely gasses that come from home cooling, electricity and

heating appliances, if people pays a little attention in their usage , they will be playing big

role in reducing global warming. Following are few measure one can take at individual

level.

1. Use Fluorescent Light Bulbs: One should immediately change incandescent light

bulbs and use fluorescent light bulbs, because these fluorescent bulbs consume only

25 % energy comparable incandescent bulbs.

2. Switch off Electric Appliances: When electric appliances are not in use, then plug

them off, because they use some energy even in off position.

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3. Change Monitor with LCD: Try to get LCD instead of a monitor, because LCD

takes about 56 percent energy than your monitor. Always keep computer screen

status off, when not in use.

4. Don’t Leave Fridge’s door open for a Long Time: Opening Fridge’s door for a

long time uses more energy, hence be quick in closing the door.

5. Uses of Solar Energy: Using solar energy instead of conventional energy save

electricity, money and environment from global warming.

6. Use Electric or Hybrid Car: You consider purchasing a hybrid or electric car, in

place of gasoline car. Gasoline car covers 20 to 30 miles per gallon, whereas hybrid

or eclectic gives you 130 to 140 miles per gallon.

7. Plant Trees At Home: Trees absorb carbon dioxide and gives oxygen. So planting

trees helps in reducing carbon dioxide levels.

8. Public Transportation: Using public transportation helps in reducing individual

fuel consumption and vehicular emissions into atmosphere.

9. Save Clean Water: One should not waste clean water, because we need more

energy for the processing of clean water.

10. Avoid Lighting at Day Time: The sun provides you light from dawn to dusk; if you

design your home with good planning you can save energy.

4. ConclusionHuman-induced climate change has contributed to changing patterns of extreme weather

across the globe, from longer and hotter heat waves to heavier rains. From a broad

perspective, all weather events are now connected to climate change. While natural

variability continues to play a key role in extreme weather, climate change has shifted the

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odds and changed the natural limits, making certain types of extreme weather more frequent

and more intense.

Continued emission of greenhouse gases will cause further warming and long-lasting

changes in all components of the climate system, increasing the likelihood of severe,

pervasive and irreversible impacts for people and ecosystems. Limiting climate change

would require substantial and sustained reductions in greenhouse gas emissions which,

together with adaptation, can limit climate change risks. Change should take place at

individual level to bring down the temperature and save mother Earth.

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References: U.S. EPA (U.S. Environmental Protection Agency). 2015. Inventory of

U.S. greenhouse gas emissions and sinks: 1990–2013. EPA 430-R-15-004.

IPCC (Intergovernmental Panel on Climate Change). 2014. Climate change 2014: Mitigation of climate change. Working Group III contribution to the IPCC Fifth Assessment Report. Cambridge, United Kingdom: Cambridge.

International Energy Agency, 2014b. CO2 Emissions from Fuel Combustion (2014 Edition). Available at: http://www.iea.org/bookshop/648CO2_Emissions_from_Fuel_Combustion

Book: An Inconvenient Truth: The Planetary Emergency of Global Warming and What We Can Do About It - Al Gore

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