Climate change: Major changes in temperature, precipitation, winds, storms, and other weather patterns over a period of several decades or longer. (Source: Environmental Protection Agency)

As preservationists our work intersects with a variety of different industries and fields, and one of the hardest things is making sure you are speaking the same language. In the area of climate change, sometimes it is hard to remember the difference between mitigation and adaptation, or even know what acronyms like COP, LCA, or EUI mean.

But you are not alone! To get you started in understanding some of the key terms in the field of climate change we've put together a list of commonly used phrases and terms. While not comprehensive, it should provide you the confidence you need as we work to show how historic preservation is climate action.

Adaptation: Taking action to prepare for, and adjust to, current and projected impacts of climate change.

Avoided Impacts: Carbon emissions and other impacts that are avoided when a building is reused rather than replaced with a comparable new structure.

Benchmarking ordinances: Policies that require building owners to measure, report, and disclose annual building energy use.

Building performance standards: Outcome-based policies and laws aimed at reducing energy use and/or carbon emissions from existing buildings to meet defined performance targets.

Carbon budget: The maximum cumulative amount of carbon dioxide that can be emitted without causing global average temperatures to increase beyond defined targets (1.5°C and 2.0°C). Exceeding these targets would greatly increase the risk of catastrophic and irreversible climate impacts.

Climate justice: Many of the people and places most impacted by climate change are least responsible for causing these changes. Climate justice seeks to address the causes of climate change while also addressing its inequitable economic, social, environmental, and public health impacts.

COP (Conference of the Parties): An international climate meeting held each year by the United Nations, bringing together countries that have joined (or are “party to”) the U.N. Framework Convention on Climate Change (UNFCCC). The first COP was held in Berlin, Germany in 1995. COP28 was held in Dubai, United Arab Emirates in 2023.

Decarbonization: Actions to reduce and eliminate carbon emissions from building construction and operations. This includes switching from oil and gas to all-electric systems that are powered by renewable energy sources and reducing the use of high carbon building materials for construction, rehabilitation, and maintenance.

Deconstruction: The process of dismantling a structure to maximize the recovery of reusable material. Sometimes called “construction in reverse” or “unbuilding,” deconstruction removes a building by selective disassembly of structural and non-structural building components and involves skilled labor rather than mechanical means such as bulldozers and wrecking balls. (Source: BuildReuse.org)

Embodied carbon emissions: In the building industry, embodied carbon refers to the greenhouse gas emissions created as part of the manufacturing, transportation, installation, maintenance, and disposal of building materials. (Source: Carbon Leadership Forum)

Energy Star: A voluntary program that measures the consumption of energy and water in buildings, as well as carbon emissions. Energy Star Portfolio Manager is a tool used by government agencies and property managers to track building performance over time using utility data. (Source: EnergyStar.gov)

EUI (Energy Use Intensity): A measure of the energy used to operate buildings. Similar to miles-per-gallon figures used to track vehicle efficiency, EUI refers to the annual amount of energy used (measured in British Thermal Units or BTUs), divided by the square footage of the space. Buildings with low EUI ratings are more energy efficient.

Mitigation: Measures to reduce the amount and speed of future climate change by reducing emissions of heat-trapping gases or removing carbon dioxide from the atmosphere.(Source: U.S. Global Change Research Program)

Net Zero Emissions: Greatly reducing carbon emissions to the point that “residual emissions that can be absorbed and durably stored by nature and other carbon dioxide removal measures.” (Source: United Nations Climate Action)

Operational carbon emissions: Carbon emissions produced as part of building use, including heating, cooling, lighting, and equipment operations.

Paris Agreement: A breakthrough international climate accord signed and adopted by 195 countries in 2015, the Paris agreement seeks to “substantially reduce global greenhouse gas emissions to hold global temperature increase to well below 2.0°C above pre-industrial levels and pursue efforts to limit it to 1.5°C above pre-industrial levels.”

Passive House: A building construction and retrofit technique that prioritizes robust insulation, careful air sealing, natural ventilation, passive solar heating, limited glazing, and other energy-saving measures.

Renewable Energy: Energy resources that are naturally renewing such as solar, wind, hydro, geothermal, wave action, and tidal action.

Resilience: Capability to anticipate, prepare for, respond to, and recover from climate impacts with minimum damage.

Thermal bridging: Occurs when conductive building materials such as concrete and steel create a “bridge” that allows heat to transfer between the interior and exterior of building surfaces. Thermal bridges waste energy and should be avoided through proper design and construction.

Tipping points: The Intergovernmental Panel on Climate Change (IPCC) defines tipping points as “critical thresholds in a system that, when exceeded, can lead to a significant change in the state of the system, often with an understanding that the change is irreversible.” Examples of potentially devastating and irreversible climate tipping points include the collapse of polar ice sheets, thawing of permafrost, and major changes in key ocean currents. (Source: European Space Agency)