Global Warming and Climate Change Group-7.pptx
- 1. True Underlying Reason Behind Global Warming and Climate Change: Anthropogenic or Beyond Who is Responsible? We humans? Or the nature itse Or Both…
- 2. Team • 1st Speaker:-17.02.03.030(IshtiqaueAhmed) • 2ndSpeaker:-17.02.03.090( MarufAhmed) • 3rd Speaker:-17.02.03.038(Md.SalehNoorShowrov) • 4th Speaker:-17.02.03.130( KalyanDebnath) • 5th Speaker:-15.02.03.106(Md.Aslammahmud).
- 3. Our stance in reasoning • Some anomalies fact hints towards non-anthropogenic factors regarding affecting the Climate Change and Global Warming and we think there are other reasons from nature affecting it. • As for example, such facts are- • 1)Medieval Warm Period:-The Medieval Climate optimum or the Medieval Climate Anomaly was a time of warm climate in the North Atlantic Region that lasted from 950 C.E. to 1250 C.E. and other regions got colder meanwhile such as the TROPICAL PACIFIC. Average global mean temperatures of that time have been calculated to be similar to that of the early-mid- 20th century warming. Industrial revolution was not noticed like today’s one. • 2)Extinction of Maya Civilization:-Delivering the Gordon R. Willey lecture, Turner detailed evidence that two major droughts resulted in the decline and depopulation of that civilization which happened roughly between 850 and 1000 A.D. At that time Earth was comparatively warmer. • 3) There was not much burning of fossil fuels 1000 years ago while it was still global warming then.
- 4. These facts at least hints that there are other causes behind the Global Warming and Climate Change.
- 5. • 2nd speaker: • Maruf Ahmed(17.02.03.090)
- 6. Global Warming and Climate Change Terms and Causes And, Climate change is a long-term change in the average weather patterns that have come to define Earth's local, regional and global climates. Global warming is a gradual increase in the earth's temperature generally due to the greenhouse effect caused by increased levels of carbon dioxide, CFCs, and other pollutants or due to natural causes.
- 7. Causes • Anthropogenic Causes Of Climate change 1. Oil and Gas. Oil and Gas is used all the time in almost every industry. 2. Deforestation. Deforestation is the clearance of woodland and forest, this is either done for the wood or to create space for farms or ranches. 3. Waste. 4. Power Plants. 5. Oil Drilling. 6. Transport and Vehicles. 7. Consumerism. 8. Farming. 9. Industrialization. 10. Overfishing.
- 8. Major Greenhouses Gases are • Caron-dioxide(mainly) • Methane:- Concentrations nearly doubled in the last years. • CFC:- Heat absorption and trapping capability ranges from hundreds totimes more than carbon dioxide. • Highly stable compound, so even if production stops at current level, their effect is expected to linger at least another century • Nitrous Oxide:- • agricultural application of fertilizer and fossil fuel burning. • Stable compound, so effect will persist for several decades even if production is completely stopped. • Water vapor-High heat storing capacity.
- 9. Why Carbon dioxide is mainly responsible for Global Warming as Greenhouse Gas- • Carbon dioxide molecules in the atmosphere absorb long-wavelength infrared energy (heat) from the Earth and then re-radiate it, some of it back downward. Oxygen and nitrogen don’t interfere with infrared waves in the atmosphere. As CO2 soaks up this infrared energy, it vibrates and re-emits the infrared energy back in all directions. About half of that energy goes out into space, and about half of it returns to Earth as heat, contributing to the ‘greenhouse effect.’
- 10. • 3rd Speaker: • Md. Saleh Noor Showrov(17.02.03.038)
- 11. Natural Factors Behind Global Warming and Climate Change
- 12. 1)Earth’s own Feedback Loops
- 13. 1)Earth’s own Feedback Loops • a)Positive Feedback Loop:- it will accelerate a response, making the climate much warmer or colder. For example:- water vapor feedback loop. • - b)Negative Feedback Loop:- it will self-regulate to create stability within the system. For example:- Solubility pump of the ocean.
- 15. 3)Atmospheric Transparency • Dust and Aerosols absorbs light, cooling the atmosphere. Aerosols can influence the Earth's climate in two ways. When the sky is clear (devoid of clouds), aerosols can reflect incoming sunlight back to outer space – the direct effect. This blocks part of the energy that would have reached the surface, thus having a cool effect on the climate.
- 16. 4)Roughness of the Earth’Surface • Laminar Air flow smoothly over smooth earth surface but causes friction with rough surface because of which kinetic energy is given off as heat. Vegetations around earth surface also act as rough objects to cause friction
- 17. 5)Albedo Effect • Light surfaces reflect more heat than dark surfaces. This is called the albedo effect. Albedo is an expression of the ability of surfaces to reflect sunlight (heat from the sun). • When the Earth's temperature dropped because of its position in orbit around the Sun, and the tilt of the axis, the ice sheets grew. This in turn caused more heat to be reflected and the ice. Albedo is one of the major properties that controls how much energy is absorbed by the surface of the Earth, the cloudiness and ground cover are important factors in climate models. sheets to expand further. • Darker colored vegetation lead to Global Warming while lighter colored vegetation lead to cooling. • For Example: Grass in a meadow will reflect between 25 – 30% of energy.
- 18. 6)Ocean Conveyor Belt • The global ocean conveyor belt is a constantly moving system of deep- ocean circulation driven by temperature and salinitycharacterized by strong northward movement of upper warm waters of the gulf stream in the Atlantic ocean. The process goes on as shown: Ocean currents appears to be related to water temperature, air pressure, storms, weather over periods around a single upto decades And effect can be upto 10 times stronger than observed in the past century, and larger, over a period of a few decades.
- 19. 7)El nino effect Wind move the surface water away from the shore, cold water rises with nutrients, which in turn promotes growth of algae resulting in growing fish population leading to growing bird population. Occurs in seven yearly cycles • Ocean water becomes warmer • Upwelling stops, nutrient can’t rise • Poor algae growth poor fish population sea birds leave or die • High rainfall and flooding in Peru • Droughts and fires become common in Australia and Indonesia • Warm ocean water provides an atmospheric heat source, so El Nino changes global atmospheric circulation.
- 20. • 4th Speaker: • Kalyan Debnath(17.02.03.130)
- 21. Effects of Climate Change rising maximum temperatures. rising minimum temperatures. rising sea levels. higher ocean temperatures. an increase in heavy precipitation (heavy rain and hail) shrinking glaciers. thawing permafrost.
- 22. Effects of Global Warming • More frequent and severe weather. • Higher temperatures are worsening many types of disasters, including storms, heat waves, floods, and droughts. • Higher death rates. • Dirtier air. • Higher wildlife extinction rates. • More acidic oceans. • Higher sea levels due to ice cap melting being overall accelerated.
- 23. Effects from Sea level Rise This will threaten people living in the coastal Regions mostly. Erosion of beaches, making structure more vulnerable to damage from waves will occur. This leads to further expense as investment costs for dams, dikes are to be constructed to protect structures. Groundwater supplies for coastal communities are also threatened due to Coastal erosion and rise in sea level, increased hydrostatic pressure of sea water table, manages to cause saltwater intrusion in ground aquifer freshwater tables.
- 24. Ways to mitigate these changes • There is nothing human beings can do control the natural factors behind Global Warming and Climate Changes. • However anthropogenic causes(global warming) are expected to be doubling the rate of these changes. So as human beings contributing to save life forms and normal habitat for living beings, we can take measures reducing and controlling the man made factors behind Global Warming and Climate Change at least.
- 25. Our ways tto reduce these changes:-
- 26. • 5th Speaker: • Md. Aslam Mahmud(15.02.03.106)
- 27. Coming to Conclusion • We always blame Greenhouse gas emission such as CO2 from man made sources as those are directly visible to us. CO2 can not be removed from earth and it is a compulsory requirement for photosynthesis biological reaction in plants which is providing the must element oxygen for our survival. • Though scientist and some long old facts indicates existence of other facts behind Global Warming and Climate Change, basing on these facts we can not only blame anthropogenic reasons.
- 28. References:- https://en.wikipedia.org/wiki/Medieval_Warm_Period • https://news.harvard.edu/gazette/story/2020/02/new-clues-about-how-and-why-the-maya-culture-collapsed/ • https://byjus.com/biology/global-warming/ • https://sciencing.com/5-causes-global-warming-8232444.html • https://news.climate.columbia.edu/2021/02/25/carbon-dioxide-cause-global-warming/ • https://sustainabilitymag.com/top10/top-10-causes-global-warming • https://www.iea.org/reports/multiple-benefits-of-energy-efficiency/emissions-savings • https://climateatlas.ca/why-climates-change • https://gml.noaa.gov/outreach/info_activities/pdfs/TBI_understanding_feedback_loops.pdf • Albedo Effect: https://www.npolar.no/en/fact/albedo/ • https://energyeducation.ca/encyclopedia/Albedo • https://aspirantforum.com/2020/11/22/effect-of-albedo-on-global-warming/ • https://www.essearth.com/why-albedo-is-important-for-our-melting-ice-caps/ • Milankovitch cycle not responsible for climate change: https://climate.nasa.gov/ask-nasa-climate/2949/why-milankovitch-orbital- cycles-cant-explain-earths-current-warming/ • https://slideplayer.com/slide/7881776/ • https://www.gfdl.noaa.gov/aerosols-and-climate/ • https://phys.org/news/2016-04-nasa-global-earth.html • https://www.eesi.org/topics/geothermal/description • https://www.nrdc.org/stories/are-effects-global-warming-really-bad