Global warming
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Global warming is caused by greenhouse gases like carbon dioxide and methane trapping heat in the atmosphere. The largest sources of these gases are fossil fuel combustion and industrial activities. As greenhouse gas levels have increased since the Industrial Revolution, the planet has warmed considerably according to temperature records. Continued warming is projected to raise sea levels and intensify weather events like hurricanes, with potentially devastating consequences for humans and wildlife. Mitigating further global warming will require transitioning to renewable energy sources and implementing carbon emission reductions on a global scale.
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Global warming
- 2. Global warming • Global warming is caused by green house gases, which trap in the sun’s infrared rays in the earth’s atmosphere, which in turn heat up the earth’s atmosphere. • These green house effect warming is called as global warming. • The main gases contributing to green house effect are : Carbon Dioxide Water Vapour Methane Nitrous Oxide The largest producers of these gases are: • Thermal power plants- burn the fossil fuels. • Road vehicles and Industries.
- 3. History of Earth’s Climate • Earth was formed ~4.6 billion years ago • Originally very hot • Sun’s energy output was only 70% present • Liquid water was present on surface around ~4.3 billion years ago (zircon dating) • Life appeared ~3.8 billion years ago • Photosynthesis began 3.5-2.5 billion years ago This Produced oxygen and removed carbon dioxide and methane (greenhouse gases)from atmosphere. Earth went through periods of cooling (“Snowball Earth”) and warming • Earth began cycles of glacial and interglacial periods ~3 million years ago
- 4. Sun Earth’s Temperature Solar Energy Radiative Cooling
- 5. Earth’s Atmospheric Gases Nitrogen (N2) Oxygen (O2) Water (H2O) Carbon Dioxide (CO2) Non- Greenhouse 99% Gases Methane (CH4) Greenhouse 1% Gases
- 6. Annual Carbon Emissions Year Carbon (109 metric tons) Annual carbon emissions Atmospheric CO2 Atmospheric CO2 average 8 6 4 2 0 1955 1965 1975 1985 1995 2005
- 7. Winter Temperatures 17 16 15 14 13 12 11 10 1880 1900 1920 1940 1960 1980 2000 Year Summer Temperatures 25 24 23 22 21 20 19 18 1880 1900 1920 1940 1960 1980 2000 Year Annual Temperatures 22 21 20 19 18 17 16 15 1880 1900 1920 1940 1960 1980 2000 Year Temperature (°C) Historic Temperatures
- 8. Consequences of Global Warming Increase in Temperature • Ice sheets of Antarctica and Greenland is melting. • Increase in mean sea level. • It will engulf low lying countries. • Excluding the ice caps and ice sheets of the Arctic and Antarctic, the total surface area of glaciers worldwide has decreased by 50%. • The Himalayan glaciers, the sources of Asia's biggest rivers —Ganges, Indus, Brahmaputra, Yangtze, Mekong, Salween and Yellow—could disappear by 2035 as temperature rise. • Approximately 2.4 billion people live in the drainage basin of the Himalayan rivers. • India, China, Pakistan, Bangladesh, Nepal and Myanmar could experience floods followed by droughts in coming decades
- 9. Changes in Antarctica Ice Mass 1000 800 600 400 200 0 -200 -400 -600 2003 2004 2005 Ice Mass (km3) Year
- 10. Melting Glaciers – Mt. Kilimanjaro
- 11. Increase in Hurricanes? • Two studies showed the total number of hurricanes has not changed • However, the intensity of hurricanes has increased (more category 4 and 5 hurricanes and cyclones) • Probably due to higher sea surface temperatures (more energy) • Difficult to know if this trend will continue
- 12. Effects • Polar Bears Require pack ice to live Might eventually go extinct in the wild • Sea turtles Breed on the same islands as their birth Could go extinct on some islands as beaches are flooded • Other species may go extinct as rainfall patterns change throughout the world • Effects on Humans • Introduction of some new diseases. • The bacteria are more effective and multiply much faster in warmer. • The increase in temperature has led to increase in the microbes that cause diseases.
- 13. Drought in Africa Lake Faguibine Lake Chad
- 14. Mitigation of Global Warming • Conservation Reduce energy needs Recycling • Alternate energy sources Nuclear Wind Geothermal Hydroelectric Solar Fusion?
- 15. Conclusions Possible Solutions to Global Warming Global warming is happening Most warming is probably the result of human activities Avoid deforestation Avoid usage of gases which pollutes atmosphere.
Editor's Notes
- This slideshow present an overview of global warming issues, last updated 8/11/2006. A more detailed analysis of global warming issues is available at http://www.godandscience.org/apologetics/global_warming.html, including a printable PDF version.
- This is a big picture examination of the earth’s climate The Earth was formed around 4.6 billion years ago And was originally very hot However, the Sun’s energy output was only 70% of what it is presently Liquid water was present on the surface around 4.3 billion years ago, according to zircon dating However, much of earth’s early history was erased during late heavy bombardment, which took place around 3.9 billion years ago
- If amount of solar energy absorbed by the earth is equal to the amount radiated back into space, the earth remains at a constant temperature.
- Likewise, the earth’s atmospheric gases affect the ability of the earth to radiate the Sun’s energy back into space. Nitrogen and Oxygen make up 99% of the earth’s atmospheric gases and are non-greenhouse gases. Water, Carbon Dioxide, and Methane make up 1% of the earth’s atmosphere, but are greenhouse gases, since they cause the earth to retain heat.
- Despite this rapid increase in carbon emissions, only about half the carbon can be detected in the atmosphere. The remainder of the carbon dioxide is being dissolved in the oceans or incorporated into trees.
- The previous graph does not tell the entire story, since temperature changes have not occurred to the same extent during different seasons. For example, in Los Angeles, temperatures have risen pretty dramatically over the last 120+ years. However, summer temperatures have not risen as quickly. In fact, summer temperatures in the 1880’s were about the same as summer temperatures in the 2000’s. In contrast, winter temperatures have risen much more consistently and dramatically. Global warming models have predicted that warming will be greater during the winter than the summer.
- These are the result of the GRACE study, which show decreasing ice mass in Antarctica from 2002 to 2005.
- Mount Kilimanjaro is the poster child of the global warming movement, since most of the glacier has disappeared over the last 30 years. However experts agree that the shrinking of the Mount Kilimanjaro glacier is more the result of deforestation of the surrounding area than changes due to global warming.
- The year 2005 was marked by a number of destructive hurricanes. What this just an unusual year or a trend that has resulted from climate change? Two studies showed the total number of hurricanes has not changed However, the intensity of hurricanes has increased (more category 4 and 5 hurricanes and cyclones) This increase in intensity is probably due to higher sea surface temperatures, which provide more energy to the storms. However, it is difficult to know if this trend will continue.
- Some species of wildlife could be greatly affected by global warming For example, polar bears require pack ice in order to hunt and live. If all pack ice disappears, they might eventually go extinct in the wild. Sea turtles breed on the same islands as they are born on. They could go extinct on some islands as beaches are flooded before new beaches are produced. Other species may go extinct as rainfall patterns change throughout the world.
- Africa's drought troubles began well before greenhouse gases increased to any appreciable degree. The inhabitants of Northern Africa have systematically cut down trees for firewood for thousands of years. The result has been that transpiration has decreased, decreasing rainfall and expanding the Sahara Desert. Similar deforestation is now occurring over much of Africa. The result is that the deserts of North, South and East Africa are expanding, leading to drought. Coupled with global warming induced changes in precipitation, it is likely that the peoples of much of Africa will be suffering from drought and starvation in the coming decades.
- Methods of mitigating global warming include Conservation Reduce energy needs, such as electrical usage, petroleum usage, reduced packaging Recycling, which uses less energy to produce products compared to Another way to reduce carbon emissions is to use alternate energy sources, such as Nuclear Wind Geothermal Hydroelectric Solar Fusion?