Earth has enough resources to meet everybody’s need, but not for anybody’s greed—

—Mahatma Gandhi

We are yet to find out if any other planet beyond Mother Earth sustains life in any form. But, as of now Earth is our home; the most cozy and comfortable abode of the mankind, the other animals and plants species. This Earth is full of excitement and surprises, is rich in diversity and colours. But we have plundered its resources, defiled the environment and used it as the garbage bin for ages now. Our self-esteem as the “Masters of the Universe” has received many setbacks after man-made calamities and disasters that have befallen us in recent times. We have realized our mistakes and taken corrective measures. Many more need to be taken. Next few decades in this 21st century will decide not only our love for Mother Earth, but also our own survival on it.

Two hundred million years back when dinosaurs roamed around the earth, entire landmass of the earth was connected in one giant super-continent called PANGAEA. Later it broke and separated out, giving rise to the present continents. Changes have taken place not only in the geological formations; in biotic and abiotic worlds too changes have become the rule. Today, dinosaurs are extinct; so are millions of other animals and plants species. But with all that, which remains, human beings share this unique planet. There cannot be any concept of supremacy or dominance in this Earth. With 71% water and 29% land, this planet has created its environment in a highly balanced manner. Disturbing this balance would undoubtedly cause irreversible changes.

Earth is the third planet from the Sun at a distance of about 150 million kilometers. It takes 365.256 days for the Earth to travel around the Sun in its orbit and 23.9345 hours for the Earth to a complete rotation around its own axis. It has a diameter of 12,756 kilometers. We are blessed with the unique atmosphere which makes life possible. Oxygen in the atmosphere makes Earth the only planet in the universe to harbour life. Our planet’s rapid spin and molten nickel-iron core gave rise to an extensive magnetic field, which, along with the atmosphere, shields us from nearly all harmful radiation coming from the Sun and other stars. Earth’s atmosphere protects us from meteors, most of which burn up before they can strike the surface with calamity.

Scientists all around the world have collected enormous information about Earth, its physical and chemical composition, diversity of life, besides all bio-geo-physical changes. The search for knowledge started more than 5000 years ago and it still is going on uninterrupted. Exploration of Earth is going on in various spatial scales. Earth gives the same kind of wonders and excitement from microscopic scale to the macroscopic studies of space, but with a great unifying effect. No single discipline or subject answers all questions coming to our minds. We need physics, chemistry, life sciences, mathematics & geometry, astronomy, philosophy, modern computers and information technology, everything to know about the wonders of this planet. Thus study of earth is holistic in approach; it brings the people and disciplines together; it demands objective details; it necessitates the synthesis of facts. But more than anything else, this quest for knowledge promotes innovations, improvisations and discoveries. For the sake of convenience we have categorized these studies into some major groups like atmosphere, lithosphere, hydrosphere, noosphere, biosphere and energy, the omnipresent source of our survival in all these spheres. We have just introduced these six categories below for an initial idea about the topic and related issues.

Atmosphere: The protective blanket
Earth is protected by a blanket of air, we call the atmosphere. Energy from the sun warms the atmosphere causing vertical movement of air, known as wind. Similarly when oceans are heated, oceanic currents form. The interactions of air, water and solar energy compose our weather. We study temperature, rainfall and humidity as parameters that indicate the conditions of the weather. Climate is the average of all weather conditions of an area over a long period of time.

Clouds are collections of tiny droplets of water suspended in the air. Clouds will precipitate in the form of rain, hail or snow. Clouds are classified according to the shapes and altitude. The four basic types of clouds are Cirrus, Cumulus, Stratus and Nimbus. Cirrus is a high white feathery clouds usually associated with the fair weather. Thick puffy masses of clouds that look like the head of cauliflower are called Cumulus. Stratus clouds occur in extensive layers with striations. Clouds that produce precipitations are Nimbus clouds. Most of the clouds can be explained as one of these or in combinations.

Weather is a day-to-day state of the atmosphere and it is a dynamic system. Climate is the average state of weather and is relatively more predictable. Climate includes the average temperature, amount of rain, humidity, days of sunlight and many such variables that are measurable for a site. Recently the issue of world’s climate change has been debated much and it refers to the variation in the earth’s global climate or regional climate over time. Though such changes come most of the time due to processes internal to the earth, but the present problem is the major changes that are visible due to the anthropogenic (human) activities. Lifestyle, resource use pattern and even behaviour of people are very much determined by the climate and weather. Local and regional climatic changes determine the agrarian life and the activity pattern of the people and also the kind of biodiversity of the region. Due to ruthless commercialization of activities and excessive usage of resources we are now facing the deleterious changes at global level. Even minor activities at the local scale which are repeated in innumerable localities may have global repercussions.

Water is the elixir of life; the indispensable resource on earth. Livelihood and life of people depends on water. Only 4.2% of the available water in the earth is in the usable form. Development of any society is intimately linked with the availability of water. Most of the ancient civilizations developed on the banks of river due to this fact. Usage, availability and quality of water, conservation issues related to water are the problems which need immediate attention of the people. Water availability depend very much on rainfall pattern on a regional scale but it depends more on the management strategies of people at the local scale. The major sources of water for people are river, ponds lakes and ground water storage. The surface water bodies such as rivers, ponds and lakes work as a source of water as well as the home for diverse organisms. They distribute and replenish the ground water system. Ground water is the most critical part that supports the life line of any land. It depends on the atmospheric and climatic patterns as well as the surface water regimes such as rivers, ponds and lakes. It annually gets renewed through precipitation and percolation. Rivers and other wetlands play a significant role in the replenishment and distribution of available water for the people.

Depletion, pollution and wastage are the three major problems regarding the water resource utilization. There is an urgent need to document planning and implement the conservation schemes for water at all scales.

Rocks undergo corrosion due to physical, chemical and biological processes and give rise to soil. Soil is the living skin of the earth. Without soil, the present life on earth is not possible. All terrestrial life forms develop from soil, directly or indirectly nurtured by soil and perish to soil. Human development and prosperity was possible due to the diversity and richness of the soil in terms of the useful mineral content and life in the soil.

Study of Land and land use pattern can give a holistic approach to our environment and give much insight into the human life of that area and their resource utilization trends. Study of soil characteristics is important in understanding the local environment and the support of earth towards human life and biodiversity. Deforestation and the resultant erosion can change landforms. Currently the total arable land is 13.31% of the land surface, with only 4.71% supporting permanent crops. Nearly 40% of the Earth’s land surface is presently used for cropland and pasture, or an estimated 1.3×107 km² of cropland and 3.4×107 km² of pastureland. Sustainable use of this land has become very significant issue for our survival on earth.

Biodiversity is a relatively new word that means the variety of life forms in a unit area. An ecosystem is a geographical unit with its own components such as climate, soil, water and a variety of interlinked biota. All geographical areas or habitats do not harbour same kind or extent of biodiversity. India is a mega diversity country and study on biodiversity associated with various ecosystems and regions are important for the management, sustainable utilization and conservation. The living species play a variety of roles in the ecosystems in which they exist.

The key issues regarding biodiversity is its depletion, lack of knowledge of distribution of its components, and sustainable utilization. Students can develop very many small projects on biodiversity distribution, functioning and utilization of this diversity.

The key issues in the Indian urban centers are the lack of civic facilities, hygiene, proper waste disposal system, pollution at all levels, poverty and so on. Architectural variations in the houses, utilization of resources for the construction purposes in different areas are interesting topics to look in to.

The problems of pollution and climatic hazards are a major concern for the public health. Many of the materials generated by both natural and man-made processes have been recognized as health hazards. For example inhalation exposure to asbestos, silica and some mineral rich dust are known to trigger certain diseases. Exposure to automobile exhaust, urban air pollutants, cement and other factory exhausts, debris from the building demolitions and construction sites and the dust particles carrying pathogens are also causes of concern. Many minerals and natural chemicals entering our body system through food and water cause diseases; but many also cure them. This might be an interesting area to study about the beneficial and harmful effects. Issues such as high level of arsenic and fluoride in the water, low or high level of calcium and phosphorus in the soil etc directly or indirectly affect the human health.

Energy: the Driving Force
Energy is a critical resource derived from the Sun and the earth, crucial to the development of modern society. At present we are very much dependent on the non- renewable resources such as mineral and fossil fuels. But they are not unlimited. In fact, many sources have already shown declining trends. A prudent use of energy, planning and search for the alternative sources are the ways ahead. The major fossil fuels are petroleum, coal, and natural gases, which still largely influence our lifestyle. Electricity can be produced from different sources and it is the major energy input for lighting, all electrical equipments and machines. All our communication and production systems almost completely depend on electrical energy. Rural areas still use cattle and human energy for traction and other activities to some extent.

Key issues on a national scale are the production of additional energy, planning of sustainable production, efficient distribution and optimal use to maximize productivity. In the local scale, use of locally available renewable sources of energy, the wastage of energy and the methods of conservation are most critical ones. Students can develop small projects related to the energy accounting of house or any other working unit and suggest energy conservation measures.

Planet Earth, Our home – explore, share and care - is the theme of Children’s Science Congress for years 2008 and 2009. This offers all of us a great opportunity to come together and infuse the spirit of science to the young minds through scientific study of all issues related to the planet earth. The UNESCO declaration of 2008 as the International Year of Planet Earth will further boost up our endeavours.