IB Environmental systems and societies Topic 6: Atmosphere and Climate Change Key Definitions

Aerosols are tiny solid or liquid particles suspended in the atmosphere.

Albedo refers to how much solar energy is reflected by the Earth's surface.

Anthropocene means “the age of humans”, emphasizing the unprecedented role humans play in altering Earth’s geology, atmosphere, and biosphere.

Biome shift refers to the movement of major vegetation and ecosystem types towards the poles or higher elevations due to long-term climate changes.

A biome is a group of ecosystems that share similar climatic conditions, regardless of their geographic location.

Carbon neutrality (or climate neutrality) refers to achieving a net-zero carbon footprint by balancing the amount of carbon dioxide emitted with the amount removed from the atmosphere, typically through carbon offset initiatives like reforestation or carbon capture and storage.

Carbon offsetting is compensating for emissions by investing in activities that remove or reduce an equivalent amount of carbon elsewhere.

Carbon sequestration is the process of capturing atmospheric carbon dioxide (CO₂) and storing it in solid or liquid form.

A carbon tax is a financial charge placed on the carbon content of fuels, encouraging businesses and individuals to reduce their carbon footprint.

Climate describes the average weather conditions in a region over a long period, typically 30 years or more.

Climate justice refers to the fair treatment of all people and countries in policies and impacts related to climate change. It recognises that those who contributed least to the problem are often the most affected.

Climate justice emphasizes fairness, ensuring those who contribute the least to climate change are not the ones who suffer the most.

A critical threshold is the moment at which a system crosses a boundary, triggering rapid state change.

Decarbonization refers to the process of reducing or eliminating carbon dioxide (CO₂) emissions from energy production, transportation, industry, and other sectors.

A dynamic atmospheric system is one in which gases, energy, and particles are continuously transformed and redistributed through interacting physical and chemical processes.

Ecosystem resilience refers to an ecosystem’s ability to recover from disturbances and return to its original state or adapt to a new equilibrium.

Electromagnetic radiation is energy that travels as oscillating waves through space and includes radio waves, infrared, visible light, ultraviolet, X-rays and gamma rays.

The enhanced greenhouse effect refers to additional warming caused by increased concentrations of greenhouse gases from human activities.

Intentional, large-scale modification of the climate system to counteract global warming, usually without reducing emissions at the source.

The greenhouse effect is a natural warming process where greenhouse gases absorb and re-emit infrared radiation, preventing heat from escaping into space.

Greenhouse gases are atmospheric gases that absorb infrared radiation emitted from the Earth’s surface and re-radiate it back, contributing to atmospheric warming.

The Hadley cell is the largest and strongest atmospheric circulation cell, driven by intense heating at the equator and responsible for tropical climates and the formation of deserts in the subtropics.

Hindcasting is a method for validating climate models by comparing their simulated past climate with actual historical records.

Ice cores are cylinders of ice drilled from glaciers or ice sheets that contain trapped gases and particles from past atmospheres.