We are the students of Ahsanullah University of Science And Technology from civil Engineering department .We have prepared a presentation for our Environmental Engineering lll course to explain global warming and climate change.Global Warming and Climate Change is hot topic nowadays .So this presentation was made to discover main causes behind this situation . Is Anthropogenic or natural?? In this presentation we have tried to explain this .

1. Global Warming and
Climate Change
Who is responsible?
We humans or the nature itself..

2. Your Logo or Name Here
Global Warming
Global warming is the long-term rise in the
average temperature of the Earth's climate
system. It is a major aspect of climate change and
has been demonstrated by direct temperature
measurements.
Climate Change
Climate change occurs when changes in
Earth's climate system result in
new weather patterns that remain in place for an
extended period of time. The climate has
increasingly been affected driving global warming.

3. Forces causing the climate change
• Volcanism
The eruptions considered to be large enough to affect the Earth's climate on a
scale of more than 1 year are the ones that inject over 100,000 tons of SO2 into
the stratosphere.This is due to the optical properties of SO2 and sulfate
aerosols, which strongly absorb or scatter solar radiation.
• Plate tectonics
The position of the continents determines the geometry of the oceans and
therefore influences patterns of ocean circulation.The locations of the seas are
important in controlling the transfer of heat and moisture across the globe, and
therefore, in determining global climate. Over the course of millions of years,
the motion of tectonic plates reconfigures global land and ocean areas and
generates topography.This can affect both global and local patterns of climate
and atmosphere-ocean circulation.
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4. • Orbital variation
A change in the earth’s orbit or the intensity of the sun’s radiation could change
triggering warning or cooling.
Milankovitch Cycles – has been found to be consistent with timing of variations
of interglacial change.
• Earth as a wobbling top
• Rotates in a elliptical → circular → elliptical orbit around the sun
• The angle of tilt on its own axis changes
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5. The Wobbling top effect
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6. Tilt about the axis
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7. • Solar Cycles:
Sun goes through periods of hotter and cooler cycles, which has an impact on
solar energy and cosmic rays.
• Eccentricity
The cycle takes approximately 100,000 years
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8. Increased concentrations of greenhouse gases
• According to IPCC AR5WG1 Summary for Policymakers 2013,The major
causes of current climate change are primarily greenhouse gases, and
secondarily land use changes, and aerosols and soot.
• The Increased concentrations of greenhouse gases are due to burning of fossil
fuels:
Burning the oil, coal & natural Gas
Release large amount of Carbon dioxide
Carbon dioxide trap heat in our atmosphere, causing global warming.
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9. Greenhouse Gas Emissions
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10. Land use change
• Deforestation:
• Contributor to global warming and cited as one of the major causes of
greenhouse effect
• Both the decay and burning of wood release stored carbon dioxide to the
atmosphere.
• Deforestation may cause carbon stores held in soil to be released
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12. Aerosols and soot
• While aerosols typically limit global warming by reflecting sunlight, black
carbon in soot that falls on snow or ice can contribute to global warming.
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13. Your Logo or Name Here 13
Chart from NASA

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Experts Opinion
• The earth is always getting colder & warmer said Richard Lindzen
Professor of Massachusetts Institute of Technology. “It is always
changing. In fact this is true for any fluid –covered planet,”
• According to scientist Lindzen, “We don’t know why but it’s perfectly
clear that glaciers change even though the temperature is cooling at
the place that they’ve occurred”
• The extent of the human contribution to modern global warming is a
hotly debated topic in political circles, particularly in the US. During
a recent congressional hearing, Rick Perry, the US energy
secretary, remarked that “to stand up and say that 100% of global
warming is because of human activity, I think on its face, is just
indefensible”.
• However, the science on the human contribution to modern
warming is quite clear. Humans emissions and activities have caused
around 100% of the warming observed since 1950, according to the
Intergovernmental Panel on Climate Change’s (IPCC) fifth
assessment report.
• Similarly, the recent US fourth national climate assessment found
that between 93% to 123% of observed 1951-2010 warming was
due to human activities.

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Conclusion
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 Considering the above information and what the
experts say, in our opinion the drastic impact due to
Global Warming and Climate Change is because of
the driving force lead by humans and it is our
responsibility to take actions.

16. Your Logo or Name Here
Team
Abu Bakar Siddik
Arnob
ID: 16-02-03-008
16
Rohit
Chakraborty
ID: 16-02-03-010
Md. Armaan
Hossain
ID: 16-02-03-012
Salma Afia Mim
ID: 16-02-03-015
Tonmoy Paul
ID: 16-02-03-004

17. Thank You