Climate Change and Global Warming

Biography

Biography: Julie L Skullestad

Abstract

Statement of the problem: Buildings account for a large share of the global GHG emissions. UN Habitat estimates that 3 billion people will need a new home in the next 20 years due to population growth. The climate change impact (CC) of construction and operation of buildings may triple by 2050 if business as usual is practiced to meet the demand. Extensive migration to cities combined with emission reduction targets calls for dense urban areas with high-rise buildings. This allows for efficient energy use and less transport. However, building tall comes with a “CO2-premium”: Tall buildings of steel and concrete require stronger structures, and have greater use of materials per floor area than low buildings. It is therefore crucial to use materials with lower CC. Long-lived timber materials act as a carbon storage, and require less energy in production. Methodology: Life cycle assessment (LCA) has been utilized to compare the CC of functional equivalent load bearing structures in timber and concrete for high-rise buildings. The structures are analysed with several LCA methodologies, covering both attributional and consequential LCA. Conclusion & Significance: Constructing with timber has a great potential of reducing the CC of high-rise buildings, compared to concrete structures. The CO2-premium of building height is substantially less significant for timber structures than concrete structures. Hence, the CC saving potential is increasing with building height for tall structures. The reduction potential varies with regions and production technologies for material production. However, most cases show a significant reduced CC for the timber structures. If the potential for recycling and reusing the materials after the building’s life cycle is taken into account, the timber structures have an even greater advantage, as the materials can be incinerated with heat recovery to substitute other means of heat production.