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How Is Climate Change Caused? Climate change reflects a change in the energy balance of the climate system, i.e. changes the relative balance between.

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Presentation on theme: "How Is Climate Change Caused? Climate change reflects a change in the energy balance of the climate system, i.e. changes the relative balance between."— Presentation transcript:



3 How Is Climate Change Caused? Climate change reflects a change in the energy balance of the climate system, i.e. changes the relative balance between incoming solar radiation and outgoing infrared radiation from Earth. When this balance changes it is called radiative forcing. The processes that cause such changes are called forcing mechanisms. They are of two types:-

4 Internal Forcing Mechanisms External Forcing Mechanisms

5 Internal Forcing Mechanisms Natural changes in the components of earth's climate system and their interactions are the cause of internal climate variability, or "internal forcings." Scientists generally define the five components of earth's climate system to include Atmosphere, hydrosphere, cryosphere, lithosphere (restricted to the surface soils, rocks, and sediments), and biosphere. Its major component is Ocean Variability.


7 External Forcing Mechanisms External forcing mechanisms can be either natural (e.g., changes in solar output) or anthropogenic (e.g., increased emissions of greenhouse gases due to increased human activities). It consists of the following-

8 The sun is the predominant source for energy input to the Earth. Both long- and short-term variations in solar intensity are known to affect global climate. Over approximately 4 billion years, the energy output of the sun increased and atmospheric composition changed. Solar output also varies on shorter time scales, including the 11-year solar cycle and longer-term modulations. Solar intensity variations are considered to have been influential in triggering the Little Ice Age, and some of the warming observed from 1900 to 1950.Interestingly, a 2010 study suggests, “that the effects of solar variability on temperature throughout the atmosphere may be contrary to current expectations.”

9  Slight variations in Earth's orbit lead to changes in the seasonal distribution of sunlight reaching the Earth's surface. There is very little change to the area-averaged annually averaged sunshine; but there can be strong changes in the geographical and seasonal distribution. The three types of orbital variations are variations in Earth's eccentricity, changes in the tilt angle of Earth's axis of rotation, and precession of Earth's axis.  IPCC [Intergovernmental Panel on Climate Change] notes that combined together, these produce Milankovitch cycles [the collective effects of changes in the Earth's movements] drove the ice age cycles; CO 2 followed temperature change during some hundreds of years which amplified the temperature change.

10  Volcanic eruptions release gases and particulates into the atmosphere. Eruptions large enough to affect climate occur on average several times. The eruption of Mount Pinatubo in 1991, the second largest terrestrial eruption of the 20th century affected the climate substantially. Global temperatures decreased by about 0.5 °C (0.9 °F). The eruption of Mount Tambora in 1815 caused the Year Without a Summer. These types of volcanic eruptions cause global warming and mass extinctions.  Although volcanoes are technically part of the lithosphere, which itself is part of the climate system, IPCC explicitly defines volcanism as an external forcing agent.

11 The movement of tectonic plates affect both global and local patterns of climate and atmosphere-ocean circulation.  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. Because of the stabilizing effect of the oceans on temperature, yearly temperature variations are generally lower in coastal areas than they are inland. A larger supercontinent will therefore have more area in which climate is strongly seasonal than will several smaller continents or islands.

12 Analysis of ice in a core drilled from a ice sheet such as the Antarctic ice sheet, can be used to show a link between temperature and global sea level variations. The air trapped in bubbles in the ice can also reveal the CO 2 variations of the atmosphere from the distant past, well before modern environmental influences. The study of these ice cores has been a significant indicator of the changes in CO 2 over many millennia, and continues to provide valuable information about the differences between ancient and modern atmospheric conditions.

13 Humans have a great hand in increasing the rate of climate change. This is because-  Reckless Cutting Of Trees  Increase In The Consumption Of Carbon Products  No Recycling  Meaningless Use Of Electricity  Increase In The Pollution Of Rivers


15 Sea level is rising -During the 20th century, sea level rose about 15 cm (6 inches) due to melting glacier ice and expansion of warmer seawater. Models predict that sea level may rise as much as 59 cm (23 inches) during the 21st Century, threatening coastal communities, wetlands, and coral reefs. Warmer temperatures affect human health - There have been more deaths due to heat waves and more allergy attacks as the pollen season grows longer. There have also been some changes in the ranges of animals that carry disease like mosquitoes.


17 The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface, energy is transferred to the surface and the lower atmosphere. As a result, the temperature there is higher than it would be if direct heating by solar radiation were the only warming mechanism. Strengthening of the greenhouse effect through human activities is known as the enhanced (or anthropogenic) greenhouse effect. This increase in radiative forcing from human activity is attributable mainly to increased atmospheric carbon dioxide levels.

18 Global warming is the continuing rise in the average temperature of Earth's atmosphere and oceans. Global warming is caused by increased concentrations of greenhouse gases in the atmosphere, resulting from human activities such as deforestation and burning of fossil fuels. This finding is recognized by the national science academies of all the major industrialized countries and is not disputed by any scientific body of national or international standing.

19  Melting Of Polar Glaciers  Extreme Rise In Sea Level  Flooding Of Coastal Areas  Submerging Of Low Lying Islands  Increase In Mortality Rate  Depletion Of Ozone Layer  Decrease In The Percentage Of Total Land Mass

20 We Have Some Small Clippings To Show What Global Warming Will Do To Our Mother Earth… And After That Some Photos…






26 Change a light-Replacing a regular light bulb with a compact fluorescent one saves 150 pounds of carbon dioxide each year. Drive less-Walk, bike, carpool. All of these things can help reduce gas consumption and one pound of carbon dioxide every month. Recycle more and buy recycled-Save up to 2,400 pounds of carbon dioxide each year just by recycling half of your household waste. Check your tires-Properly inflated tires mean good gas mileage which results in less consumptions of petrol and CO2 level is minimized.

27 Plant a tree-A single tree can absorb one ton of carbon dioxide over its lifetime. Turn off electronic devices when not in use-Simply turning off your TV, computer and other electronic devices can save each household thousand of pounds of carbon dioxide each year. Stay informed-about environmental issues, and share your knowledge with others. Together, we can and do Make Every Day Earth Day!

28 Advantages Of Climate Change You may be thinking that we are going mad. But some people think that a few degrees of temperature increase won’t matter much, and besides, warmer climate is better at least in cold countries. This will lead to fewer cold related deaths, longer growing seasons and lower heating bills.




32 We Hope That You Have Learnt The Way To Live A Greener And Healthier Life.

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