is for Astenosphere

The Earth is composed of many layers, each with different properties. The surface is made of the crust and lithosphere (where tectonic plates are located), and then goes the asthenosphere, the mantle, the outer core, and the inner core. The asthenosphere is the third layer of the Earth and is made of liquid rock or magma. As the tectonic plates in the crust/lithosphere shift, they often either move together (convergent plates) or move apart (divergent plates). Convergent plates can often cause volcanoes, because the subduction that occurs allows the release of the liquid rock and magma from the astenosphere, directly below the plates. 

is for B-horizon

The soil of the earth is made of many different layers that are composed of different materials. Generally, these layers are labeled as the "horizons" of the soil including the O horizon (made of organic material), the A horizon (topsoil made of minerals and lots of nutrients), the B horizon, and the C horizon (made from the plant material and partly weathered rock). The B horizon is called subsoil and is made from leached minerals. This is the third layer of the solid and is also the largest part of the soil. The characteristics of the soil this deep allows for metal salts/roots to grow here. 

is for Carbon Cycle

The carbon cycle describes the way that carbon circulates through our atmosphere, ground, and water. Recently, because of the burning of fossil fuels, humans have been speeding up the carbon cycle, by taking minerals and rocks, containing carbon, out of the ground that is meant to stay there for thousands of years. Because of this, the earth is now feeling the effects of global climate change due to carbon emissions. 

is for Demographic Transition Model

The demographic transition model is a graph that shows the flow of the human population throughout time as a country becomes more and more industrialized. There are four stages, with a fifth stage that is not completely proven because it is happening in only a few countries in the world today. 

is for Eutrophication

Eutrophication is the addition of excessive nutrients, especially excess runoff fertilizer, to a body of water that causes excessive algae growth to occur. The nutrients from the runoff provide the algae with the "food" it needs to excessively grow, which blocks the sun from the rest of the organisms that need it. to survive. This, along with the lack of oxygen that is now needed due to the increased amount of organisms, causes a massive die off in the ecosystem.

is for Fracking

Fracking is a technique used in order to extract natural gas from the Earth. Natural gas is a greenhouse gas that is very commonly used for energy, due to its cheap and (mostly) environmentally friendly characteristics. Fracking uses pressurized liquid in order to break apart rocks and let out the gas inside of them. Because of this technique, fracking can sometimes cause earthquakes and water contamination due to the chemicals that are used.

is for Geothermal Energy

Geothermal energy is a renewable source of energy that involves using naturally heated water from the Earth's core in order to produce steam and turn a turbine. This is an extremely effective source of renewable energy, especially near areas that have excess to natural hot springs. Geothermal energy has a large start off cost, but is very cheap to maintain after that. Also, it has very few negative environmental impacts. 

is for Hadley Cell

A Hadley Cell is a pattern of air circulation that occurs in Earth's atmosphere. This is a pattern of air circulation that has air rising near the equator and flowing towards the poles. This pattern was discovered by George Hadley, whom it was obviously named for as well. 

is for Igneous Rock

There are multiple different types of rock, each describing rock that is in a different stage of the rock cycle. The rock cycle moves rock matter through the stages of igneous, metamorphic, sedimentary, and magma. The general forces to change stages in the rock cycle include heat, pressure, weathering, erosion, compaction, melting, and cooling. The rock cycle starts when magma comes up from the deeper layers of the Earth. This magma is cooled down into the igneous rock. With the addition of heat and pressure, the rock changes to metamorphic rock and can either be melted back into magma or uplifted to the Earth's surface. If uplifted, the rock can get weathered or compressed into the sedimentary rock where it can be melted or pressurized. There is no specific order of the rock cycle, and it all depends on the environment of the rocks in question. Some examples of igneous rock would include granite and basalt. 

is for J-shaped Curve

Population graphs often compare population size with time. The shape the population graph makes can be described as either a "J" or an "s" shaped curve. A "J" shaped curve usually represents exponential growth, where the population is reproducing without any limiting factors. "J" shaped curves can also be referred to as biotic potential curves, where there is a very high reproductive rate, with a general niche/diet, the ability to migrate, and organisms can access a variety of resources. This curve continues to occur until a population reaches the carrying capacity, meaning this is the maximum population that can be sustainably supported in an area. This is when overshoot occurs and the population has a small collapse until the environment can support the population again. This occurrence leads to an "s" curve, which is also called logistic growth. 

is for Keystone Species

Keystone species are species that are critical in maintaining a balance and biodiversity in ecosystems. These species, often, are not the apex predator but when they are removed from an ecosystem, the effects are felt by the rest of the food chain. For example, a sea otter is a keystone species in their ecosystem because they eat urchins so kelp forests will continue to stay healthy.

is for Leaching

Leaching is something that occurs throughout the nitrogen cycle. When water drains through soil, there is a loss of soluble nitrate which eventually leads to the loss of nitrogen in the nitrogen cycle. This occurs mostly when the soil water content exceeds the maximum water holding capacity of the soil. (this occurs naturally, and when flood irrigation systems are used)

is for Montreal Act

The Montreal Protocol was first enacted in 1987 and had the primary purpose of stopping CFCs production with a goal of zero output by the year 2000. Replacing CFCs with HCFCs will allow the ozone layer to recover from the damage that has been done to it, therefore slowing the occurrences of skin cancer, cataracts, etc. 

is for Negative Feedback

Negative feedback is the feedback that counteracts the change that has occurred in a system. This feedback is also referred to as a self-regulation system because it brings something back to homeostasis, or an equilibrium called a steady state. An example of negative feedback is when temperature increases, this can lead to a cloud cover which reflects more light and decreases the temperature. 

is for Open Pit Mining

Open-pit mining is also sometimes called open-cast or open-cut mining and involves extracting rock and minerals from a large pit or a borrow. This is a form of surface mining, that usually involves the use of large equipment, but still has the lowest cost despite the large capital investment. Despite this, it also has many negative environmental impacts.

is for Primary Succession

Primary succession occurs in an area that had previously had absolutely no life. These areas usually come from volcanic eruptions and retreating glaciers. The ecosystems start from bare, exposed rocks and exposed light. Then, after the soil has built up the nutrients it needs to support larger plants, smaller plants begin to form (like mosses and shrubs). Eventually, an ecosystem with large organisms can grow in this area. Eventually, when this area has been destroyed, secondary succession occurs. This is when an ecosystem starts with soil from a previous ecosystem that has been disturbed, removed, or destroyed (like abandoned land, fires, storms, disasters, etc). These ecosystems start with small weeds and eventually build up nutrients the same way that the previous ecosystem did.