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Last edited 30 May 2023
Earth overshoot day
 What is Earth Overshoot Day ?
Earth Overshoot Day (previously sometimes called Ecological Debt Day) marks the day when humanity’s demand for ecological resources and services in a given year exceeds what Earth can regenerate in that year.
Earth Overshoot Day is hosted and calculated by the Global Footprint Network, an international research organisation that provides decision-makers with a menu of tools to help the human economy operate within Earth’s ecological limits. The concept was originally conceived by the Global Footprint Network and the New Economics Foundation and is calculated yearly for the globe as a whole as well as on a country by country basis.
 How is Earth Overshoot Day calculated ?
The day is calculated by estimating the capacity of global ecosystems to produce the biological materials required by humans and its ability to absorb the waste material generated by humans over a year, referred to as biocapacity. This figure is then divided by the ecological footprint of humans in terms of material use, waste, emissions and so on. The result is then multiplied over the 365 days of the year to give an indicative day when effectively global resource would run out if used sustainably. After that day until the end of the year, demands are effectively being met through the depletion of natural resources and the accumulation of waste, such as carbon dioxide in the atmosphere and oceans, pushing essential global ecosystems closer to the point of collapse.
 Why is Earth Overshoot Day relevant to the construction industry ?
The construction industry and buildings in use contribute to significantly to the ecological footprint of humans. The Stockholm Environment Institute as well as other scientific groups estimate "Construction sector accounts for 50% of global resource extraction, making it the most material-intensive sector in the world". The IEA reported in 2019 that the buildings and construction sector "accounted for 36% of final energy use and 39% of energy and process-related carbon dioxide (CO2) emissions in 2018" with 11% of this from the manufacturing building materials and products such as steel, cement and glass.
In May 2023, Environment Audit Committee (EAC) that advises the Government, reported that residential and commercial buildings combined, the UK’s built environment is responsible for "25% of the UK’s greenhouse gas emissions". Concurrently the UKGBC estimates that construction, demolition and excavation accounts for 60% of material use and waste generation in the UK.
 What are the Earth overshoot days for the UK?
For the UK in 2023 and in 2022 the UK Earth overshoot day landed on May 19, after which the UK would effectively need another land mass to meet its demand, in 2019 it was May 17, in 2018 it was May 8 and in 2017 it was May 4.
 How has the Earths overshoot day changed?
In the early 1970's the average global earth overshoot day occurred in December, by the 80's it was in November, the 90's in October, by the millennium it was in September and since 2010 it has sat between the end of July and the beginning of August. In effect the past global overshoot days have been moving forward by about one month every 10 years, when they should be moving back by the same if globally we were meeting environmental goals.
Whilst formally the current period, since the last Ice age (Pleistocene) is known as the Holocene epoch, the Anthropocene is often used to describe a new geological epoch resulting from "significant human-driven changes to the structure and functioning of the Earth System, including the climate system.’ There are many and very varied estimates of when the Anthropocene is considered to have started, ranging from the early agricultural revolution or the industrial revolution to the the 1950's but all mark points significant increases in global emissions, natural resource use or waste production.
A future theoretical epoch might be considered as the point where a symbiosis exists between humans and planetary ecosystems, this might also be related back to a point where there is no earth overshoot day, or where the earths biocapacity meets ecological footprint of humans. Glenn A. Albrecht coined the terms Symbiocene to describe an epoch as a " period of re-integration between humans and the rest of nature, is the second of the master themes used to define Earth emotions."
 Further Information
- Book review, RIBA Climate Guide.
- Climate Framework: A cross industry action group initiative.
- CRC Energy Efficiency Scheme.
- Emission rates.
- Energy Act.
- Energy Performance Certificates.
- Energy Related Products Regulations.
- Energy Targets.
- Natural resource.
- RIBA Stirling Prize winners' open letter declaring climate and biodiversity emergency.
- Sustainable development.
- Sustainable materials.
- Smart cities.
- UN Sustainable Development Goals.
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