Chapter 1: Earth as a System

Chapter 1.1

A New View of Earth

Past Perceptions Meet New Issues Scientist in Earth Science use to specialize, one would steady the rocks on a mountain while another study the water and another life forms. Today Scientists realize that Earth is more than a collection of parts. Earth System Science is the study of and interaction of all parts.

The rise of Earth System Science Came about due to advances in Technology Satellites, deep diving subs, geographic information systems Better models to represent objects, processes and phenomenon.

What is a system? It’s a kind of model that can be defined as part of the universe that can be studied separately. Include time as a variable – figure future or past Closed System – something enters but can’t leave Sun tea – the closed jar doesn’t share matter with its surroundings. Open Systems – the system and its surrounding freely exchange both energy and matter Earth System Science – scientists study the flow of energy and matter between the components of the Earth System.

A Planetary System Earth is considered a closed system. However, it is not entirely closed. The atmosphere looses hydrogen atoms to space and meteorites enter the earth. Considered closed because the resource of earth are finite (limited)

Nature, Science and Human Policy Changes humans are making after realizing their impact on Earth. Recycle Environmental concerns before growth Flagstaff AZ ---water Not easy to balance human needs and wants Global warming Ozone Water and air pollution

Chapter 1.2

The Earth System’s Four Spheres The four systems interact continually affecting the others.

Atmosphere It’s the gaseous envelop that surrounds the Earth. It provides oxygen, Co2, ozone, water, vapor, clouds, rains, and snow. It is the only atmosphere in the solar system to contain free oxygen.

Geosphere Made up of all physical features on the planet except water Rock, mountains, beaches, rock layers, ocean basins, mantle, core, volcanoes

Hydrosphere Contains all the water on Earth’s surface Liquid, gas, ice Most of Earth’s water is salty. Only 3% is fresh of that 70% is in the form of ice. Only ½ of 1% is usable fresh water. All water is recycled. The water you drank today may have been some of the same water a dinosaur drank before.

Biosphere Includes all living things on Earth even people.

Interactions among the spheres All 4 spheres interact with each other Volcanoes (geo) erupts, sending ash and gases into the air (atmos) and lava and ash down into surrounding forest (bio)

Interactions change the spheres Short change – A late freeze kills vegetable plants A downpour cause roads to cave in Long term change – Erosion the continual breakdown and transportation of the solid Humans can be affected by the interaction of the spheres and they can affect the spheres Burning of fossil fuels leads to more CO2 in the atmosphere

Chapter 1.3

Cycles of Earth A cycle is a sequence of events that repeats

The Water Cycle A continuous circulation of water through the hydrosphere (p 13 diagram) Some water evaporates quickly of breathed out (transpired) by leaves of plants Evapotranspiration – cycling of water into the atmosphere by evaporation and transpiration

The Carbon Cycle A biogeochemical cycle involving the element carbon Things that release carbon into the atmosphere Breathing, decaying organic matter, burning of fossil fuels, forest fires, volcanoes

Things that remove carbon Caron Sink – where carbon is stored due to the death and burial of organisms with carbon in their tissues The ocean removes about 40% of the carbon in the atmosphere

The Energy Cycle Is the movement of energy into and out of the earth system The amount of energy in should equal the amount out. If it doesn’t the climate would get warmer. 99.985% of the energy on earth’s surface comes from the sun as solar energy. Drives; wind, currents and waves

013 is energy from the earth geothermal energy .013 is energy from the earth geothermal energy. Powers; lithosphere – (plate movement) volcanoes, geysers earth quakes and the rock cycle .0002 is tidal energy due to the pull of the moon on the ocean’s waters. To maintain the energy budget of the incoming energy 40% reflected back to space the rest is used in the earth system.

Law of Thermodynamics 1st Law Energy can not be created or destroyed only changed form one form to another. 2nd Law – when energy changes it is converted from a more useful, more concentrated form to a less useful, less concentrated form. Energy can never be recycled (like water)

The Effects of Earth’s Surface Due to the differences on earth’s surface (glaciers, water, light land and dark land) it will reflect solar energy differently. Albedo – is the percent of energy that is reflected without being changed.

Lighter colors have a higher albedo (e. g. ice) than darker colors (e Lighter colors have a higher albedo (e.g. ice) than darker colors (e.g. forest) which have a low albedo. An areas albedo can change – green field vs. a plowed field, summer green vs. winter white

Human Activities and the Cycles Human Activity can affect the interaction of the spheres and cycles Burning fossil fuels adds more carbon to the atmosphere All the actions of humans have an effect on the earth. Earth Science System tries to figure out how far and deep the effect travels.