ONE of the most problematic ingredients of climate change that has caused complex situations and untold suffering on a global scale is the issue of carbon emissions. Carbon emissions have been identified as the major culprit driving climate change which has triggered extreme heat, droughts, reduced precipitations and shortened cropping seasons, among other effects.
All these have increased in frequency and severity impacting on human livelihoods. As a result, stakeholders agree that the best place to keep excess carbon dioxide is to lock it underground.
In attempts to control and manage the worrying carbon emissions, there are two ways experts suggest which are the natural carbon sinks and the human constructed ones, largely with the circular nature in mind.
This discussion seeks to unpack the dividends, merits and demerits of investing in the natural carbon cycle or managing carbon emissions in circularity ways in the construction sector.
The construction sector is, however, also emission intensive and should, therefore, play a significant role in reducing carbon emissions by using more sustainable and less emitting materials, cut costs, improve the way of doing business and meet climate commitments using the circular approach.
Circular economy can be defined as a systems solution framework designed to tackle global challenges like climate change, waste and pollution. In this regard, building materials which emit carbon need to be substituted or properly managed. These are cement, steel, aluminium, concrete and gadgets like air conditioners and burning coal for heating and cooking. Cement production contributes to global carbon emissions during manufacturing, while also accounting for a large component of solid waste, created through construction.
In the construction sector, through circular economy, wastes should be eliminated, products and materials should be circulated, while construction waste like bricks and steel products should be regenerated rather than being thrown away. In this regard, there is need to move from the linear model to the circular economy model of reducing, redesigning, repairing and refurbishing waste materials. The idea behind circular economy in the construction sector is to manage waste, eliminate costs and improve the way of doing business. Circular economy is not just a practice, but a business model based on sustainable lifestyles.
The idea is not to completely do away with cement, concrete and steel, but to manage them, at the same time knowing their amount of carbon footprints. There are also cement types with high carbon emission content, while others have low carbon emissions because they contain more clinker (cement making material that does not require any by-products) than the types containing more by-products. Other substitutes for cement, although not at a large scale, are wooden and prefab materials.
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As for steel, the need is to promote its efficient use and its products as the demand for steel is increasing in emerging economies. Steel remains a vital component for human and industrial development through infrastructure reinforcements, buildings, transportation, household products, coach, vehicle and ship building, among others.
Wood, in the form of mass timber refers to the engineered wood products that are laminated from smaller boards or glue. Although these products are good for climate change mitigation, questions would arise about where those wooden materials came from, especially considering issues of deforestation. Furthermore, timber is also a sustainable component for reuse when the building has been demolished.
Circular economy in the construction sector begins with architectural designs of buildings, roads, bridges and industries, with the aim being to lower carbon emissions and achieve climate resilience. Modern buildings require improved air quality, circulation and natural lighting and cooling systems. Above all, buildings should never be sited on wetlands or flood plains because wetlands store more carbon and building would unlock the carbon trapped in wetlands into the atmosphere.
One other important aspect is building local and buying locally affordable and adaptable materials to the local environment. These locally available materials withstand local climate conditions including emitting less or no carbon.
In the scheme of things are natural carbon sinks which are in the form of forests, oceans, wetlands, soils and ecosystems, vegetation and mangroves, among others. The main bone of contention is that, despite numerous mitigatory efforts at global and local levels, carbon emissions continue to rise without any signs of abating.
Greenhouse gases are still being exacerbated by fossil fuels burning, industrial activities, urbanisation, deforestation and land use practices. Land use practices put more pressure on the land and are drivers of environmental damage and climate change.
Forests exist to act as captures or sinks. Forests such as national parks, protected forests, aquatic plants and crop fields such as those for sugarcane are vital in capturing carbon dioxide. The problematic nature of carbon dioxide is that while it is a productive gas, too much of it becomes dangerous. Right now, the world is grappling with too much carbon dioxide in the atmosphere.
Afforestation initiatives are also helpful for carbon sequestration, but the current efforts are weak, sporadic and haphazard.
International programmes such as Reducing Emissions from Deforestation and forest degradation are aimed at enhancing carbon stocks and sustainable management of forests. According to evidence on the ground, many forested nations are failing to manage and conserve their forests because the authorities in developing countries have opted to mortgage these God-given forests instead. This is caused by greed, parallel natural resource governance, lack of environmental stewardship against the background of the increased global demand for harvested wood products.
As these happen, net carbon dioxide is unlocked, let loose and clog the atmosphere. Protection and caring for natural forests is crucial, especially for wildlife to avoid conflict with human beings, to protect endangered species and avoiding mining in these protected areas.
This discussion has juxtaposed natural carbon sinks against human constructed ones.
While all these are sustainable efforts to mitigate carbon emissions, we are still failing to lower carbon emissions as we drift towards the point of no return.
Peter Makwanya is a climate change communicator. He writes in his personal capacity and can be contacted on: [email protected]
