Greenhouse gas emissions and energy scenarios for Durban : the implications of urban development on future energy demand and emissions.
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Cities are considered to be a major cause of climate change, as a result of city functions, which require energy and emit large quantities of Greenhouse Gases (GHGs). Therefore, cities are being targeted globally as key areas for climate change mitigation. In order to mitigate the impacts of climate change, it is important for policy makers to be able to understand the implications of possible future policy decisions and development plans on emissions. One possible way of developing forecasts is through emissions scenarios, which allow for the development of a series of forecasts based on changes in the drivers of emissions. The city of Durban is a developing city, which aims to promote economic development; however, this development would increase the demand for energy and therefore impact on the GHG emissions in the city. The aim of this study is to develop a number of GHG emissions scenarios that illustrate the implications of various development paths for the city. The methodology applied involved first identifying the gaps in existing GHG inventories for Durban and the data required to close these gaps. The data was input into the Long-range Energy Alternatives Planning (LEAP) tool, which is a physical accounting and simulation tool that allows for the creation of scenarios. Five scenarios were created to illustrate different ways in which the city might develop which are the Growth without Constraints (GWC) Scenario, the Business as Usual (BAU) Scenario, the Natural Transition City, the Slow Go City and the Low Carbon City. Lastly, a sixth scenario, the Required by Science (RBS), was not modelled but created to illustrate what would be required if Durban followed the Intergovernmental Panel on Climate Change (IPCC) stabilisation guideline of a reduction of 60% - 80% of 1990 levels by 2100. Thereafter the IPCC scenarios were downscaled from a national level to a local level using a linear downscaling methodology, in order to illustrate the implications of global development paths on the city. The different development paths had a range of impacts on emissions. Rapid economic growth, with no climate change mitigation in the GWC Scenario, results in a 6.3 times increase in emissions from the base year to 2050. If the city continues with its current policies and strategies as in the BAU Scenario, emissions will increase 3.5 times from the base year. If there is a transition to a post-industrial society, with no climate change mitigation, emissions will increase 3 fold from 2005 to 2050. The National Transition Scenario illustrated that if Durban moves towards a service sector economy, which are predominantly low carbon sector, with no climate change mitigation, emissions will still increase 3.15 times the 2005 levels. If the city is slow to respond to climate change as in the Slow Go City, emissions will increase 2.5 times from the base year. A shift in the structure of the economy and an increase in the use of renewable energy and energy efficiency (i.e. a Low Carbon City) results in reduction in emissions of 1% from 2005. These were compared to the IPCC downscaled scenarios, which followed a similar pattern. The scenarios are comparable to developing city scenarios, but illustrate that the city is lagging behind developed cities. In order to make an impact in the reduction of emissions, it is essential for the city to target the commercial and industrial sector, which is the sector that emits the highest GHG emissions. However all these scenarios are still insufficient for achieving the RBS emissions target of a 60-80% reduction from 1990 levels. Achieving this reduction would require more than a 50% improvement in energy efficiency, structural change in the economy to low energy intensive sectors and a 20% contribution of renewable energy to total energy supply.