The Kyoto Protocol was an international agreement linked to the United Nations Framework Convention on Climate Change to combat global warming by reducing GHG emissions.

Acid rain is caused by chemical reactions of sulphur dioxide and nitrogen oxides with water vapor in the atmosphere.

The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without its atmosphere.

The IUCN Red List of Threatened Species is the world's most comprehensive inventory of the global conservation status of biological species.

Water vapor is the most abundant greenhouse gas, though human activities primarily increase concentrations of CO2 and methane.

The Montreal Protocol was designed to phase out the production and consumption of substances responsible for ozone depletion.

Eutrophication is the excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen.

The Amazon rainforest is often referred to as the 'lungs of the planet' due to its massive role in absorbing carbon dioxide and producing oxygen.

Biomagnification is the accumulation of chemicals such as heavy metals or pesticides in an organism as a result of ingesting other plants or animals in which the chemicals are more widely disbursed.

Soil salinization occurs when water-soluble salts accumulate in the soil profile to a level that impacts plant growth, common in poorly drained irrigated lands.

Carbon sequestration is the long-term removal, capture, or sequestration of carbon dioxide from the atmosphere to slow or reverse atmospheric CO2 pollution.

Photochemical smog is formed when sunlight reacts with nitrogen oxides and volatile organic compounds in the atmosphere, producing ground-level ozone.

The Ramsar Convention on Wetlands is an international treaty for the conservation and sustainable use of wetlands, signed in Ramsar, Iran, in 1971.

Minamata disease is a neurological syndrome caused by severe mercury poisoning, historically linked to the release of methylmercury in industrial wastewater.

Ocean acidification is the ongoing decrease in the pH of the Earth's oceans, caused by the uptake of carbon dioxide from the atmosphere.

Permaculture is a design system for creating sustainable human environments by modeling them on the patterns and resilient features observed in natural ecosystems.

BOD measures the amount of dissolved oxygen required by aerobic biological organisms to break down organic material present in a given water sample at a certain temperature.

The Anthropocene is an informal term used by scientists to describe the current geological time period, in which human activity is the dominant influence on climate and the environment.

Carbon monoxide (CO) binds to hemoglobin more strongly than oxygen does, forming carboxyhemoglobin, which reduces the blood's capacity to carry oxygen.