OUR ENVIRONMENT What is Environment ? Our Environment is our surrounding. This includes living and non-living things around us. The non-living components of environment are land, water and air. The living components are germs, plants, animals and people.
Environmental Science• Environmental Science is the oldest science.• The scientific knowledge started developing since the time the humane being started observing the surrounding environment.• In the modern curriculum also the first subject taught on science is Environmental Science.
Habitat The Environment consists of various habitats A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism
What is a habitat?A habitat isany placewhereorganisms livetogethernaturally.It is like aneighborhoodin nature.
What does an Organism need in a habitat?Shelter Water Food
What about our habitat?Just like animals and plants, we need our own habitat. What are our needs? Shelter Food Water
The Ecosystem The interrelationships between all living things and the environment. Emphasis is on interdependence of all things. People, nature, and the earth form a delicately balanced system.
MATTER CYCLING IN ECOSYSTEMS• For hundreds of millions of years the chemicals and elements found on Earth have remained relatively constant, or in other words, they have changed very little.• The amount of one element or chemical in the Earth’s surface is practically the same as it was many millions of years ago. This consistency is one of the things that makes life on Earth possible.
Ecological Cycles BiosphereCarbon Phosphorus Nitrogen Water Oxygen cycle cycle cycle cycle cycle Heat in the environment Fig. 3-7, p. 55
Nutrient Cycles: Global Recycling ◦ Global Cycles recycle nutrients through the earth’s air, land, water, and living organisms. ◦ Nutrients are the elements and compounds that organisms need to live, grow, and reproduce. ◦ Biogeochemical cycles move these substances through air, water, soil, rock and living organisms.
The Water Cycle: Rain clouds Condensation Transpiration Evaporation Precipitation Transpiration to land from plantsPrecipitation Precipitation Evaporation Surface runoff from land Evaporation Runoff from ocean Precipitation (rapid) to oceanInfiltration and SurfacePercolation runoff (rapid) Groundwater movement (slow) Ocean storage Fig. 3-26, p. 72
Water’s Unique Properties Water is the elixir of Life It is a magical substance which is essential to the very existence of every life form on earth. There are strong forces of attraction between molecules of water. It takes a large amount of energy for water to evaporate. Liquid water can dissolve a variety of compounds. Water expands when it freezes.
Effects of Human Activitieson Water Cycle We alter the water cycle by: Withdrawing large amounts of freshwater. Clearing vegetation and eroding soils. Polluting surface and underground water. Contributing to climate change.
Effects of Human Activitieson Carbon Cycle We alter the carbon cycle by adding excess CO2 to the atmosphere through: Burning fossil fuels. Clearing vegetation faster than it is replaced. Figure 3-28
The Nitrogen Cycle:Bacteria in Action Figure 3-29
Effects of Human Activitieson the Nitrogen Cycle Adding gases (Oxides of Nitrogen) that contribute to acid rain. Adding nitrous oxide to the atmosphere through farming practices which can warm the atmosphere and deplete ozone. Contaminating ground water from nitrate ions in inorganic fertilizers. Contaminate the lakes and other water bodies (Eutrophication) by the presence of excess nitrogen compounds in the ground and surface water.
Effects of Human Activitieson the Nitrogen Cycle Human activities such as production of fertilizers now fix more nitrogen than all natural sources combined. Figure 3-30
Effects of Human Activitieson the Phosphorous Cycle We remove large amounts of phosphate from the earth to make fertilizer. We reduce phosphorous in tropical soils by clearing forests. We add excess phosphates to aquatic systems from runoff of animal wastes and fertilizers.
Effects of Human Activitieson the Sulfur Cycle We add sulfur dioxide to the atmosphere by: Burning coal and oil Refining sulfur containing petroleum. Convert sulfur-containing metallic ores into free metals such as copper, lead, and zinc releasing sulfur dioxide into the environment.
Types of Pollution Air pollution Most air pollution is caused by the burning of fossil fuels. Water pollution Disposal of sewage from houses Eutrophication Infectious agents Agricultural wastes Organic chemicals Inorganic and miscellaneous chemicals Sediments from land corrosion Radioactive substances Waste heat from power plants and industry
Types of Pollution—Continued Land pollution Pesticides – chemicals used to kill insects defined as pests. Herbicides – chemicals used to kill plant life, particularly weeds. Chemical wastes Radioactive fallout Acid rain Garbage
A new threat to the Environment /Planet.Global warming Since the late 1800’s the average global surface temperature has increased about 0.75 degrees C. Most warming has occurred since 1950.
Global Warming There is a gradual increase in the average temperature of the Earth’s atmosphere in the last 100 years…It has risen about 1°C since 1900… • Are human activities causing global warming? • What other (non-human) factors can cause global warming? • How does global warming affect our life?
Greenhouse gas are efficient in absorbing IR light…The most important greenhouse gases are:H2O – Water vapor.CO2 – Carbon DioxideCH4 – methaneThe most abundant greenhouse gas in Earth’s atmosphereis water vapor. Most of the greenhouse heating of Earth’satmosphere is due to Water vapor absorption of IRradiation emitted by Earth, and then transferring theenergy to the surrounding air molecule
Which gas is keeping the Earth warm? The major natural greenhouse gases are • water vapor, which causes about 36-70% of the greenhouse effect on Earth (not including clouds); • carbon dioxide, which causes 9-26%; • methane, which causes 4-9%, and • ozone, which causes 3-7%. Note that it is not really possible to assert that a certain gas causes a certain percentage of the greenhouse effect, because the influences of the various gases are not additive.
So, what’s the big deal if human CO2 causes1°C temperature increase? An increase in atmospheric temperature (human or natural origin) will lead to the increase in the water vapor content of the troposphere. Because water vapor is a strong greenhouse gas, the increase in H2O vapor in turn causes enhanced greenhouse effect, raising the temperature more. Higher atmospheric temperature will cause more evaporation of water Which leads to even higher temperature… Runaway Green House Effect!
Global Warming – Is it true? Most of the scientists agree that the global warming observed in the last century were caused by human activity. However, the global climate is a very complicated system. We understand the basic principle of the climate system, but we still don’t understand how nature regulates Earth’s climate over the long run, nor do we have the capability to create a realistic climate model and be able to predict with any certainty the effects of human activities on our climate system.
Ecological footprint• The ecological footprint is a measure of human demand on the Earths ecosystems.• It compares human demand with planet Earth’s ecological capacity to regenerate.• It represents the amount of biologically productive land and sea area needed to regenerate the resources a human population consumes and to absorb and render harmless the corresponding waste.
Ecological footprint• For 2006, humanitys total ecological footprint was estimated at 1.4 planet Earths.• In other words, humanity uses ecological services 1.4 times as fast as Earth can renew them.• Per capita ecological footprint (EF) is a means of comparing consumption and lifestyles, and checking this against natures ability to provide for this consumption.• As per 2006 Calculation UAE has the highest Ecological footprint in the World (10.68 global hectare per person).• For India this value is only 0.91 (See table)
Ecological footprint MOVIE• Currently (As of 2010) the earth have approximately 1.8 biologically productive hectares per person.• Most of the developed courtiers and GCC countries the ecological footprint is much larger that this.• That means if every one in the world live like the people in these countries, we would need multiple planets.• The Earth is rapidly depleting in resources and it has intensified with the rapid development in the last century.• The only way to counteract this is to take steps in reducing your own ecological footprint.
Globalization and Environment• Globalization has transformed the Environmental issues dramatically.• Worldwide liberalization of trade may provoke environmental collapse.• The major environmental concerns related to trade are • the domestic environmental effects caused by the use of imported products, • environmental effects caused by the production of exported goods, • the environmental effects caused by transport movements needed for international trade.
SAVE THE MOTHER EARTH There can be no viable future for humanity without a healthy planet. Earth, water and air support the existence of an immensely complex living system, powered by the sun. We are part of this web of life. But within a few generations, we are using up most of the earth’s stored fossil fuel resources and its end products released to the atmosphere is altering its composition. Our globalizing economic system is destabilizing the planet’s life-support systems, the very systems that support us and the future generations.