Environmental Terminology Explained

Carbon emissions

The most common greenhouse gas is carbon dioxide (CO₂), sometimes referred to as ‘carbon’. The other GHGs also have a warming effect on the earth’s atmosphere, but their potency differs from CO₂. In order to calculate the total effect of the gases, each is converted into values that are equivalent to carbon dioxide (CO₂ₑ), which are then added together.

Carbon versus greenhouse gases

Global warming is caused by the emission of greenhouse gases (GHGs). The most common of these is carbon dioxide (CO2, typically abbreviated as simply ‘carbon’), but there are many other gases that contribute to global warming, three of which include methane (CH4), nitrous oxide (N2 O), and fluorinated gases (F-gases). Each GHG has a different warming effect on the earth’s atmosphere, F-gases for example are relatively small in volume but can have a global warming potential (GWP) up to 26,000 times greater than carbon dioxide.  In order to sum the total effect of all gases, each is converted into its equivalent CO2 warming effect and all CO2 - equivalents (CO2 e) are then summed. 

Source: US EPA (2015)

Climate change

The Earth’s natural climate has historically been in a continued state of change, with naturally occurring greenhouse gases (GHGs) essential to our existence. However, human activities have directly increased these levels and, as a result, human produced GHGs are the leading cause of the earth’s now rapidly changing climate.

Comfort creep

In terms of buildings, comfort creep refers to how, over time, we become used to gradual changes in the temperature (and other areas).

Decarbonising the power sector

Decarbonising the power sector or ‘the grid’ means reducing the emissions per unit of generated electricity. The power sector has been a major success story, with carbon emissions falling by 67% between 2008 and 2019 – the biggest reduction of all sectors in the UK. This has been achieved by reducing our reliance on coal-fired power, increasing the use of renewables such as wind turbines and biomass utilisation.

Embodied carbon

This refers to the lifecycle emission of CO₂ₑ produced during the manufacture and transportation of materials, the construction process and the end-of-life aspects of a building.

Environmental Product Declarations (EPD)

An EPD is a document which transparently communicates the environmental performance or impact of any product or material over its lifetime. Within the construction industry, EPDs support carbon emission reduction by making it possible to compare the impacts of different materials and products in order to select the most sustainable option. An EPD is usually valid for five years, and is generated according to the relevant standards. Construction EPDs are based on the ISO 14040/14044, ISO 14025,EN 15804 or ISO 21930 standards.

Maintenance versus repair

Maintenance can be defined as “routine work necessary to keep the fabric of a place in good order”

Repair can be defined as “work beyond the scope of maintenance, to remedy defects caused by decay, damage or use, including minor adaptation to achieve a sustainable outcome, but not involving alteration or restoration”.

Net carbon

Balancing carbon dioxide emissions against capturing or eliminating existing atmospheric carbon dioxide is key to achieving carbon neutrality. It requires a rapid reduction in carbon emissions and, where zero carbon emissions cannot be achieved, the remaining carbon should be offset.

Operational carbon

These are carbon emissions produced during the operational or in-use phase of a building, such as through heating and lighting.

Renewable and low carbon energy sources

Different energy sources produce different amounts of GHG emissions. During the last decade, renewable and low carbon energy sources such as wind, solar and biomass have successfully replaced traditional fossil fuels like coal, gas and oil.

Retrofit

Retrofit is the process of improving the energy and environmental performance of buildings through technical interventions. Good retrofit considers the unique properties of a building including the building characteristics, building services but also very importantly, the people.

Sequestered carbon

Carbon sequestration is the process of capturing and storing atmospheric carbon dioxide and will likely play a key role in helping meet net zero targets. Natural forms of carbon storage include forests, which store carbon in their timber and within the soil.

Temperature adjusted emissions

Greenhouse gas emission from energy consumption and emissions in the buildings sector are strongly influenced by weather conditions – particularly temperatures during the winter. To allow meaningful evaluation of trends in emissions, the figures need to be temperature-adjusted.  Temperature-adjusted emission figures are undertaken by analysing the relationship between emissions data and quarterly Heating Degree Days (HDD).

(CCC, 2022b)

Thermal performance

In terms of a building, this refers to the efficiency in which it retains, or prevents the passage of heat. Materials with a good thermal performance do not readily transmit heat.