This page is part of the Earth Journalism Toolkit’s glossary.

Radiative forcing: refers to changes in the energy balance of the earth-atmosphere system in response to a change in factors such as greenhouse gases, land-use change, or solar radiation. Positive radiative forcing increases the temperature of the lower atmosphere, which in turn increases temperatures at the Earth’s surface. Negative radiative forcing cools the lower atmosphere. Radiative forcing is most commonly measured in units of watts per square meter (W/m2).

Rainwater harvesting: collecting rainwater either in storage containers or the soil mostly close to where it falls to avoid the need for infrastructure to bring water from elsewhere.

Recyclables: all materials that may be recycled, but the term is generally used in reference to the recyclable containers and paper/cardboard component of kerbside waste (excluding garden organics).

Recycling: a term that may be used to cover a wide range of activities, including collection, sorting, reprocessing and manufacture of products into new goods.

Reforestation: the direct human conversion of non-forested land to forested land through planting, seeding or promotion of natural seed sources, on land that was once forested but no longer so.

Remediation: Correction or improvement of a problem, such as work that is done to clean up or stop the release of chemicals from a contaminated site. After investigation of a site, remedial work may include removing soil and/or drums, capping the site or collecting and treating the contaminated fluids.

Renewable energy: any source of energy that can be used without depleting its reserves. These sources include sunlight (solar energy) and other sources such as, wind, wave, biomass, geothermal and hydro energy.

Resource intensity: ratio of resource consumption relative to its economic or physical output; for example, litres of water used per dollar spent, or litres of water used per tonne of aluminium produced. At the national level, energy intensity is the ratio of total primary energy consumption of the country to either the gross domestic product, or the physical output (total goods produced).

Respiration (biology): uptake by a living organism of oxygen from the air (or water) which is then used to oxidise organic matter or food. The outputs of this oxidation are usually carbon dioxide and water

Risk: Risk is the possibility of injury, disease or death. For example, for a person who has measles, the risk of death is one in one million.

Risk assessment: A process which estimates the likelihood that exposed people may have health effects. The four steps of a risk assessment are: hazard identification (Can this substance damage health?); dose-response assessment (What dose causes what effect?); exposure assessment (How and how much do people contact it?); and risk characterization (combining the other three steps to characterize risk and describe the limitations and uncertainties).