The Built Environment: Greenhouse Gas Emissions

Introduction

Statement of the problem

Climate change has become a substantial concern at the global level amongst policymakers and business leaders in the current decade. Researchers are seeking consensus on the relationship between global warming and the effects of climate change. In the meantime, there is overwhelming consensus amongst researchers that climate change is ongoing and that it has mostly likely been orchestrated by human activity (Stern 2007).

The growing carbon footprint has led many policymakers to seek to ensure that carbon emissions are reduced to the lowest levels possible in the short run. The built environment plays a critical role in supplementing government efforts to attain carbon dioxide emissions targets by 2050. For a long time, buildings have been among the largest emitters of carbon, attributable to about 1/3 of total global greenhouse gases (Shipworth & Ucci 2015).

Purpose and structure of the paper

This paper seeks to offer a roadmap towards lowering carbon emissions related to the built environment. This plan covers the building and infrastructure sectors to address operational carbon emission elements. Carbon emissions related to buildings will entail both domestic and industrial sectors. Carbon emissions in the infrastructure sector will address emissions related to operational activities such as heating and lighting. However, some infrastructure emissions that are not directly connected to support of the built environment, such as transport, will be excluded. This paper will also give an analysis of the strategies and methodology employed to move the plan forward, as well as the expected opportunities and challenges in achieving low carbon emissions by the year 2050.

The current state

Over the past decade, the energy used in construction, maintenance, and other applications in the built environment has been a major generator of greenhouse gas emissions. Domestic and non-domestic constructions are estimated to contribute to about 36% of the total greenhouse gas emissions in the UK (Giesekam et al. 2014). Industrial emissions related to the support of supply materials and other construction activities for the built environment are estimated to reach 22% (Roaf 2010). The built environment is an industry with the unique opportunity to make huge developments in cutting energy demand, promoting process effectiveness, and minimising carbon emissions.

The Green Construction Board in the UK has developed a working plan to act as a strategic tool guide for stakeholders in the built environment to understand the policies targeting carbon reduction (Reynolds 2012). These measures are necessary to guide the built environment to attain the government’s target of an 80% cut in greenhouse gas emissions by 2050. To generate the proper framework to reduce carbon emissions in the built environment, it is vital to recognise where the greenhouse gasses are currently originating.

The next section will provide an estimate of carbon emissions linked to the built environment within the last decade. Apart from carbon, the built environment is also responsible for other greenhouse gas emissions such as halocarbons and hydro fluorocarbons (Xiang-Li, Zhi-Yong, & Lin 2015).

Context

The built environment is attributable to approximately 30% of global annual greenhouse gas emissions (Langwith 2009). Following the tremendous growth in new buildings and the inadequacy of existing building stock around the world, greenhouse gas emissions have been estimated to triple by 2050if no additional measures are taken. Reducing greenhouse gas emissions by using renewable energy sources can provide employment, save funds, and create a built environment that optimises the positive environmental effect.

Greenhouse gas emissions linked to buildings primarily emanate from the buildings’ massive use of fossil fuel energy (Xydis 2009). This consumption is through either direct use of fossil fuels or from electric power sourced from fossil fuels.

Below, Figure 1 demonstrates the baseline carbon emissions profile for the period running from 1990 to 2010. The baseline approximates the capital and operational greenhouse gas emissions linked to the built environment. The presentation in Figure 1 below suggests that the built environment was responsible for nearly 210 MtCO2e of greenhouse gas emissions from 1990 to 2010. This breakdown for 2010 energy use shows that operational energy is highly used in domestic activities, particularly heating and cooking.

Analysis of carbon emissions in the built environment between 1990 and 2010
Figure 1: Analysis of carbon emissions in the built environment between 1990 and 2010 (Lockwood 2013).

Figure 2 below shows that in 1990, greenhouse gas emissions were estimated to reach 209 million tons. By 2010, this number had declined to 191 million tons. This huge change is largely due to a reduction in emissions from the domestic operational carbon sector, though the non-domestic operations also played a major role. However, to achieve the 80% reduction target by 2050, capital carbon and operational carbon emitted from the built environment will have to decline to about 42 million tons. Even though Figure 2 below indicates slight decrease in carbon emissions, further measures need to be implemented in an effort to achieve the estimated 2050 target.

Baseline emissions related to the built environment
Figure 2: Baseline emissions related to the built environment (Lockwood 2013).

Emissions and Trends

The built environment includes all residential and commercial sectors. Massive greenhouse gas emissions are produced via construction materials such as insulation and cooling systems. Essentially, energy is used during variety of activities that include:

  • Industrial manufacturing of building materials (i.e. embedded energy).
  • Transport of these materials from manufacturers to building sites.
  • The construction of the structures (i.e. induced energy).
  • Activities involved in the building (i.e. operational energy).
  • Demolition and evacuation of the building.
  • Recycling of the building parts.

Since the highest percentage of energy is used during the operational stage, the built environment should seek ways to minimise operational energy. In fact, about 80% of carbon emissions occur from activities executed within the building, such as heating, lighting, and air conditioning (Kopec 2009). A relatively lower percentage of energy is consumed during construction and other building-related activities such as maintenance and demolition. Thus, the UK government can attain substantial reductions in carbon emissions by targeting the operational phase. The key areas that need to be addressed to minimise energy use during the operational stage include:

  • Climate and location of the site.
  • Rate of energy demand, supply, and source.
  • The purpose of the building.
  • The building design and material.

The kind of environment in which a building is situated influences nearly all aspects of a building’s energy needs over its lifespan (Heijden 2014). Due to the varying climate conditions across the UK, the rate of energy consumed varies during the operational phase. Regarding location, in less-developed regions in the UK, particularly in rural regions, a huge percentage of operational energy is consumed. As these regions develop, energy use declines as innovative and less heat-intensive appliances are introduced. Similarly, the colder regions of the UK demand more energy than the warm regions. Thus, the building design and material used in the cold zones should have the capacity to conserve heat and allow optimal penetration of natural light (Haugen & Musser 2012).

The rate of energy use and the source of energy influence the operational stage in two major ways. First, house lighting, heating, and cooking all lead to the emission of carbon, methane, and nitrous oxide (Wan et al. 2011). The built environment should target innovative ways of reducing these emissions such as the use of natural energy sources. Second, the purpose of the building also determines the rate at which energy is used. For instance, if the building is designed for an industrial purpose in which proper lighting is necessary, the building design should take advantage of sunlight by installing energy-efficient ventilation.

The roadmap to 2050

The timeframe towards substantial change in carbon emissions is estimated to be 20 years. This period determines the kind of trends and projections to be employed to offer projections of the operational carbon and capital carbon sectors. The main drivers that will affect future processes in the built environment include government regulations on new infrastructure, patterns in prices and productivity, and the speed of growth in the UK economy (Lockwood 2013).

As renewable technologies become more readily accessible, affordable, and flexible, their demand is expected to continue to grow as builders increase their application in new constructions. Sustainable building, also referred to as green building, employs new designs and technology to address the demands of the market with limited or zero greenhouse gas emissions. While green buildings are still in the pilot stage in the UK, they are predicted to become widespread in the near future (Lockwood 2013).

The 80% carbon reduction framework is presented in Figure 3 below.

The 80% carbon reduction 2050 target in the building sector
Figure 3: The 80% carbon reduction 2050 target in the building sector (Lockwood 2013).

One of the main ways to reduce carbon emissions should involve electricity grid decarbonisation. The main factors that will affect the future of decarbonisation include government policy on delivering a new electricity grid, the pace of growth in the UK economy, patterns of prices and production, and the role of economic regulators (Giesekam et al. 2014). Thus, to comply with zero-carbon regulations, new buildings will be needed to be carbon free. This goal can be attained by maximising the use of effective fabrics and energy-efficient technologies. The energy sector will be expected to turn to low- or zero-carbon energy technologies.

Another approach that is yet to be given much concern by the built environment roadmap is the carbon budget. Such development presents a challenge for the building sector and is directly associated with global warming scenarios. It is broadly recognised that the built environment needs to stabilise greenhouse gas concentrations in the atmosphere to limit the chances of global warming.

This assertion implies that emission budgets need to be established and implemented. For instance, the Board on Climate Change has developed four carbon budgets for the UK (Giesekam et al. 2014). Nonetheless, keen considerations need to be assessed precisely for the built environment to ensure that it delivers in line with these national budgetary goals. Achieving low carbon emissions in the built environment is a vital aspect in the overall emissions reductions facilitated by the burgeoning decarbonisation of the electricity grid (Yu & Kim 2011).

Opportunities

There are many opportunities to propel carbon reduction and encourage responsibility and ownership of carbon in the built environment. The most prominent pollutant in the built environment is domestic emissions, followed by commercial space heating (Graham 2003). This segment offers opportunities for improvement through draught roofing or insulation for both energy-efficient methods that help domestic residents and commercial buildings to reduce energy use.

Homes and commercial structures utilise a lot of energy for cooking, heating, lighting, and other operational consumptions. Green building technologies can encourage new and old buildings to utilise less energy to achieve the same purposes, hence allowing for lower greenhouse gas emissions (Crawford & French 2008). Other strategies to promote building efficiency entail energy-efficient ventilation and air conditioning, as well as the use of energy-saving appliances and electronics. However, a fundamental change in fuel source is inevitably necessary to attain the target 80% reduction.

Solid waste disposed to landfills can be managed to produce useful products. Waste products from buildings produce carbon and methane that can be captured and used. Landfill gas is should be obtained after the decomposition of solid waste in landfills. Recycling, waste reduction, and methane capture programs are suitable ways to eliminate greenhouse gases from waste.

Wastewater treatment should also be made energy efficient, especially because drinking water and wastewater released from buildings account for about 3-4% of energy consumption in the UK (Fudge & Peters 2011). Studies estimate that massive energy savings of approximately 15-30% are currently attainable in water and wastewater plants alone. However, if the trend continues, there is a possibility that carbon emissions will fall to sustainable levels.

Beyond preaching the necessity of reducing greenhouse gas emissions, there is a need to motivate the building sector to assume responsibility and generate suitable plans to minimise emissions themselves. The UK government has the huge opportunity to promote carbon reduction in the buildings it owns, including education, public health, civil service, and transport infrastructure, which together are currently responsible for about 28% of operational emissions (Cotgrave & Riley 2012).

This goal can be achieved by utilising new design tools and innovative architectural designs. The government should also lead the way in implementing policies that encourage the use of renewable energy sources such as wind and solar energy. The use of recyclable building materials can also reduce the use of landfills and their subsequent production of carbon and methane gases.

Apart from a reduction in greenhouse gas emissions, the drive to 80% carbon reduction has an economic significance. Actualising the 80% target will lead to major business breakthroughs, particularly for entrepreneurs engaged in domestic retrofit. By issuing funds towards research and development in the building sector and by using retrofit in large numbers in the next decade, the UK could manifest itself as an innovator in the low-carbon economy. The choice of building materials determines the embodied energy of a structure and has critical implications for greenhouse gas emissions related to operational energy consumption.

Challenges to overcome

Attaining the targeted 80%, carbon reduction is a difficult task, but it is technically achievable. Achieving this milestone will call for the optimal incorporation of plausible solutions in all entities, including the use of advanced technologies. Minimising emissions in the built environment is hugely reliant on the rate of decarbonisation of the grid industries. The UK can attain the estimated changes if the government acts swiftly in reforming the electricity market.

Undoubtedly, the existing electricity market has served the entire nation well in ensuring energy supplies since the baseline year, 1990. However, the changing nature of the global energy supply coupled with the increasing greenhouse gas effect has raised the need for a different energy infrastructure. To effect the desired change, the government should target investment in renewable energy sources at the right pace to ensure a sustainable cost plan for these technologies (Collins, Natarajan, & Levermore 2010).

Transitioning to a zero-waste economy is a challenging task, but it can be achievable if appropriate techniques are used. The UK government has introduced the landfill tax to reduce the quantity of waste disposed to landfill. These efforts aim to create an environment where waste is reused and recycled. For instance, technology such as anaerobic processes can be employed to generate energy from waste.

The UK government should also be committed to ensuring that new buildings are zero carbon and that their costs are affordable to facilitate sustainable green development. The government should invest in research and development activities to gain insight about the quantities of methane produced, collected, and released from landfill zones. This knowledge will increase the level of certainty regarding the evidence base for the waste industry and will provide correct data about waste’s contribution to global greenhouse gas emissions (Atkins & Emmanuel 2014).

Since greenhouse gas emissions are a global concern, the UK should collaborate with an organisation such as the EU to move the world toward a low-carbon economy (Alhorr & Elsarrag 2014). The UK should forge strong bilateral agreements with the rest of the world to share best practices and experiences in the built environment in the move to a low-carbon economy. Consistent emphasis on building design, reuse, and recycling and continued research will be necessary to delve deeper into the field, minimise carbon emissions, and develop new energy-efficient designs by 2050 (Alhorr, Eliskandarani, & Elsarrag 2015).

Conclusions

The built environment is the highest contributor of greenhouse gas emissions, so it offers the greatest opportunity for the reduction of greenhouse gas emissions. In this light, policies that support more energy-efficient strategies and minimise carbon emissions should be advocated. The built sector should adhere to green building standards, and there should be a set score to be achieved in order to qualify for a building permit.

Even though such policies might not produce substantial reductions in carbon emissions in the short run, the progress will grow over time towards 2050.The built environment has vast potential for minimising carbon emissions at relatively affordable costs. Policymakers have a wide array of opportunities available for each of the key policy goals.

The UK government needs to support more carefully developed research into the effects of built environment practices so that energy efficient-development can be achieved. Particularly useful future research initiatives include those that seek to understand spatial trends within cities, changing housing preferences, and more compact land use patterns. By cutting up to 10% of operational energy use in the country, the decrease in carbon emissions would be significant.

The construction sector should not hesitate to implement new policies despite the learning curve associated with trying them. Once the built sector abides to best practices, there will be huge cost savings—hence eliminating many of the key obstacles. Thus, given the uncertainties, it is advisable to progress steadily and evaluate outcomes while considering new research within the field of the built environment.

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