Global warming is widely perceived to be one of the most important environmental issues facing the world today. The Intergovernmental Panel on Climate Change (IPCC) concluded that the observed temperature increase since the middle of the 20th century was very likely the result of increasing greenhouse gas concentration due to human activities such as the use of fossil fuel and deforestation. Buildings account for 40% of the world’s energy consumption and one third of global greenhouse gas emissions. The IPCC identified that the reduction of energy consumption and greenhouse gas (GHG) emission from the building sector has one of the highest benefit-cost ratios among many possible mitigation measures across different sectors.
While buildings produce GHG emissions at all stages of their life-cycle including construction, operation, maintenance and demolition, the operation of a residential building generally accounts for 80-90% of the total emissions, mainly from space heating and cooling, hot water, lighting and other household appliances. Therefore, GHG emissions from building operation may contribute considerably to the global warming. It should be noted that the warming climate may add more pressure on building energy consumption and subsequently GHG emissions. In particular, the increase in building cooling energy consumption and its related GHG emissions in a growing warm climate can further exacerbates global warming that leads to even higher cooling demands in the future.
Climate change mitigation and adaptation are two general approaches in response to global warming. Climate mitigation is designed to reduce GHG emissions and in return to reduce the global warming impact. Climate adaptation is designed to adjust actions in the society to cope with climate changes that are already happening or are the likely consequences of current GHG emissions.
In practice, climate adaptation is implemented by reducing exposures and vulnerability. Vulnerability is defined as the state of susceptibility to harm from exposure to changing environment and the absence of capacity to adapt. While the exposure to potential climate change is unlikely avoided, the reduction of vulnerability can be achieved by the improvement in the adaptive capacity that is the ability to respond to climate variability and change, to reduce or moderate the likelihood and the magnitude of harmful outcomes, to cope with the consequences, or to take advantage of opportunities. Considering vulnerability in building energy demand, climate adaptation can be implemented by increasing buildings’ adaptive capacity, which is represented by their enhanced energy performance to reduce the growing energy demand as a result of climate change.
There have been a number of studies investigating climate change impacts on residential building energy consumption and associated carbon emissions. Radhi made a comprehensive review in this research area. It was concluded that efforts should not only focus on the reduction of GHG emissions, but also equally on the preparation for the inevitable climate change. To reduce GHG emissions by improving building energy performance may include the implementation of additional insulation and better ventilation, double glazing, shading devices and thermal mass etc. Others include fuel choice and adoption of renewable energy technologies. Kwok and Rajkovich suggested that both GHG mitigation and climate adaptation should be added to building energy codes and thermal comfort standards, though cost-effective integrated measures should be addressed.
In Sydney Australia, a ‘Zero-Emissions House (AusZEH)’ experiment was developed by “Timber flooring Sydney” to demonstrate new technologies and innovative solutions for significant reduction in GHG emissions from the residential sectors. Recently, Newton and Tucker investigated potential pathways to decarbonising current housing sector through a scenario modelling study. However, these studies were based on current climates, and the impact of global warming on building energy consumption and GHG emissions were not considered.
The authors investigated climate change impacts on space heating and cooling energy requirements of Australian residential buildings in different regional climates ranging from cold to hot humid. It was demonstrated that the global warming may considerably affect the effectiveness of mitigation schemes represented by the emission reduction policies through enhancing the thermal performance of building envelop. The previous investigations were limited to energy requirement and GHG emissions in association with residential building space heating and cooling. However, adaptations to accommodate the impacts of climate change should be considered in terms of total residential building energy consumption and GHG emissions that have yet been addressed. This is due to the facts: 1) adaptation to reduce global warming impact should be implemented by considering an entire residential house as a single entity and measured to reflect the changes in the total energy consumption and GHG emissions; 2) adaptation can be developed not only by reducing heating and cooling energy demand, but also via enhanced energy efficiency of appliances as well as the use of renewable energy.