Our environment

OUR ENVIRONMENT

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 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.

Environmental Science

HabitatThe 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 place where organisms live together naturally.

It is like a neighborhood in nature.

What does an Organism

need in a habitat?

Shelter

Food

Water

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.

The Ecosystem

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.

Fig. 3-7, p. 55

Nitrogen

cycle

Biosphere

Heat in the environment

Phosphorus

cycle

Carbon

cycle

Oxygen

cycle

Water

cycle

Ecological

Cycles

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.

Fig. 3-26, p. 72

PrecipitationPrecipitation

Transpiration

Condensation

Evaporation

Ocean storage

Transpiration

from plants

Precipitation

to land

Groundwater movement (slow)

Evaporation

from land Evaporation

from ocean Precipitation

to ocean

Infiltration and

Percolation

Rain clouds

RunoffSurface runoff

(rapid)

Surface

runoff

(rapid)

The Water Cycle:

Water’s Unique PropertiesWater 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 Activities on 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.

The Carbon Cycle:

Figure 3-27

Effects of Human Activities on 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

Nitrogen Cycle

Effects of Human Activities on 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 Activities on the Nitrogen Cycle

Human activities such as production of fertilizers now fix more nitrogen than all natural sources combined.

Figure 3-30

OXYGEN CYCLE

The Phosphorous Cycle

Figure 3-31

Effects of Human Activities on 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.

The Sulfur Cycle

Figure 3-32

Effects of Human Activities on the Sulfur CycleWe 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.

Environmental Pollution Pollution is the harmful

alteration of our environment by our own actions.

Pollutants – either unwanted byproducts or our activities or the residues of things we have made, used, and thrown away.

Air Pollution Water Pollution Land Pollution Noise Pollution

© Norman R. Rowan/Stock Boston

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 WarmingThere 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 – methane

The most abundant greenhouse gas in Earth’s atmosphere is water vapor. Most of the greenhouse heating of Earth’s atmosphere is due to Water vapor absorption of IR radiation emitted by Earth, and then transferring the energy 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 causes 1°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.

• The ecological footprint is a measure of human

demand on the Earth's 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, humanity's 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 nature's 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

• 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.

Ecological footprint MOVIE

• 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.

Globalization and Environment

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.

THANK YOU