Earth's energy system

                   Earth's energy system

Physical processes

 Earth is constantly changing as energy flows through the system. Geologic, fossil, and ice records provide evidence of significant changes throughout Earth's history. These changes are always associated with changes in the flow of energy through the Earth system. Both living and non- living processes have contributed to this change.

Energy flows

Energy flows on Earth can take many forms. In some cases the energy flows are constant, such as the decay of naturally-occurring radioactive materials within the Earth. This process releases heat to Earth's interior, which helps to drive the motion of plate tectonics at a fairly constant rate.

In other cases the energy flows can vary over time, such as with the carbon cycle

Energy drives the flow of carbon between different reservoirs. Carbon can exist in carbonate rocks (like limestone), stored fossil fuels (like coal, oil, or natural gas) in the atmosphere, in the oceans, or in the molecules of biological organisms. Large scale burning of fossil fuels is removing stored organic carbon from the Earth's crust and releasing carbon dioxide into the atmosphere. This has changed the composition of the atmosphere so that it traps outgoing heat more effectively. Humans have therefore changed the natural energy balance of the Earth.

Even without humans, the Earth has experienced changes in its energy balance. Over the course of geologic time there have been drastic changes in the flow of energy through the Earth. For example, the Earth was entirely molten early in its geologic history and was covered in ice during the PreCambrian period. The Sun was once 30% dimmer than it is today.

Energy drives the Earth system

When students learn about Earth processes, they generally focus on the process itself, such as plate tectonics, tides or stream flow. These ideas illustrate how all of Earth's processes are driven by energy. Energy transfer can be thought of as a the driving force of the Earth system.

Most of the energy in the Earth system comes from just a few sources: solar energy, gravity, radioactive decay, and the rotation of the Earth. Solar energy drives many surface processes such as winds, currents, the hydrologic cycle, and the overall climate system. Gravity makes rivers and other materials flow downhill and creates tides (from the Moon's gravitational pull). Radioactive decay creates heat in the Earth's interior, while Earth's rotational forces influence currents of air and water.

These ideas have considerable crossover with the Climate Literacy Principles 1 and 2. Climate Literacy Principle 1 focuses on the Sun as the primary source of energy for Earth's climate system, while Climate Literacy Principle 2 explains that greenhouse gases affect the energy balance of the Earth. Carbon dioxide and other greenhouse gases trap outgoing radiation that would otherwise exit the Earth system, thus warming the atmosphere. It also summarizes the carbon cycle through different carbon sinks and sources.

Earth's internal heat and other small effects

The geothermal heat flux from the Earth's interior is estimated to be 47 terawatts and split approximately equally between radiogenic heat and heat leftover from the Earth's formation. This comes to 0.087 watt/square metre, which represents only 0.027% of Earth's total energy budget at the surface, which is dominated by 173,000 terawatts of incoming solar radiation.[10]

Human production of energy is even lower, at an estimated 18 TW.

Photosynthesis has a larger effect: photosynthetic efficiency turns up to 2% of the sunlight striking plants into biomass. 100 to 140[11] TW (or around 0.08%) of the initial energy gets captured by photosynthesis, giving energy to plants.

Other minor sources of energy are usually ignored in these calculations, including accretion of interplanetary dust and solar wind, light from stars other than the Sun and the thermal radiation from space. Earlier, Joseph Fourier had claimed that deep space radiation was significant in a paper often cited as the first on the greenhouse effect.

Greenhouse effect

Greenhouse gas put very much effect on earth energy system. it accelerated earth soil breakdown and make new soil. high greenhouse gas very much effect in atmosphere, so that living organism and earth energy system should be affect that.