�ݺ�ߣ

Editor's Notes

• #16: The rationale for this analysis is the overlooked yet very important role of materials for GHG emissions. 1) Materials have become more important as a share of global emissions, growing to over 11Gt and 23% of global emissions in 2015. 11Gt correspond to the share of GHG emissions from agriculture, forestry, and land use change combined, yet they have received much less attention. Global climate change mitigation efforts have traditionally focused on improving energy efficiency and accelerating the transition to renewables. While this is key, we need to pay greater attention to material efficiency, as without it, it will be nearly impossible and substantially more expensive to keep global warming below 1.5° C. 2) This is also because emissions from materials production are “hard to abate” through energy measures. Electrification of production, for example from iron to steel, is difficult, as is fuel switching and CCS. Better energy efficiency in the production is possible and important but not enough. 3) Therefore, using materials more efficiently down the value chain – i.e. in the material-intense end products – is the most direct measure to reduce emissions. 4) Importantly, the technologies are available today, proven to be safe and create various co-benefits with operational emissions savings, as well as socioeconomic benefits such as better housing or mobility.
• #18: So how do we improve system-wide efficiency in these sectors? 7 strategies are important here: Leaner design or ‘using less material by design’, for example leaner load-bearing structures in buildings Fabrication yield improvements, the so to day “traditional efficiency” that reduces waste in the manufacturing process or improves scrap reuse Enhanced end-of-life recovery and recycling of materials means for example the recycling of steel of a discarded car Product lifetime extension refers to better repair and maintenance of buildings or cars Remanufacturing and reuse of components prolongs the lifetime of components, in the same or another vehicle or house More intensive use refers to the overall smarter utilization of a car or house. It means that floor space is used without rooms that are not really being used, or that buildings do not remain empty – which can reduce the total floor space needed in a country without hampering the quality of living. In cars, this means that cars are standing around empty less, and are used by more persons – for example in ride-pooling models. The questions is – how impactful are these strategies for mitigation in different regional and sector contexts?
• #19: With this purpose, the IRP report looks at important material-intense example sectors. Most materials are used in construction and manufacturing, and within these sectors, private vehicles and residential housing are particularly important, because They use large amounts of materials They provide essential services to society They create high economic value And they show significant potential for system-wide efficiency increases
• #20: Looking at G7 homes, we can see these strategies (all together) can reduce 35% of total housing life-cycle emissions, and can reduce emissions from material production for houses to almost zero. First, we see the annual emissions of homes in 2016. This is not a scenario, this is the reality today, where both material emissions – here in orange – are significant, as well as emissions from heating and cooling of houses. Now we look at a scenario in 2050. This scenario assumes a reduced building rate in 2050 in comparison to 2016, as most houses will have been built by then and building is mainly about replacing. Also, this reference scenario includes quite ambitious energy measures, so high action on insulation and clean energy supply. However, even with these measures, the emissions are still over 700Mt in 2050 yearly. Now we apply material-efficiency strategies on top of those energy measures. And we can see that we can further reduce 35% of the overall emissions, and almost 100% of the remaining material emissions.
• #21: If we look at the same sequence in China and India (here aggregated), the total emissions are much higher but the logic is similar. 1) New building today (2016) is very high, and so are emissions. 2) New building will peak some time between 2016 and 2050, so that the annual emissions from materials are lower in 2050 than today. Cooling and heating emissions are substantial, despite ambitious energy measures and transition to clean energy. 3) On top of this scenario in 2050, we now apply the material efficiency strategies, which can significantly reduce material emissions, and operational emissions, too. Overall emissions are more than halved and material emissions are reduced to a fifth of the reference scenario.
• #22: As mentioned, the report does not only look at a comparison of 2050 annual emissions scenarios. It also check what the implications are for emissions from today until 2060. We can see that cumulatively, the reductions from G7 homes are around 20% through material-efficiency strategies. This of course depends on how fast we start implementing them. We can also see that more intensive use of homes – i.e. eliminating underutilization of essentially “wasted” space, would save by far the most emissions. Better utilization of space means less need for new building, plus freed materials that could be reused for other purposes – if recycling capabilities are in place. The use of recycled materials is very important, too, as well as the use of renewable materials such as sustainably sources wood. Leaner design has less impact in G7 countries where new building need is low, it would have more impact on growing countries like India. It is interesting to note that most of the strategies predominantly reduce the need for virgin materials and connected emissions. More intensive use can also significantly reduce heating needs, and wood-use can reduce cooling needs.
• #23: The model also looks at cars. Here we look at the complete car fleet in the G7. First we look at the emissions from the fleet today. Material emissions are significant with 30Mt, however appear small in comparison to the massive fuel emissions, here in blue. In 2050, the reference scenario assumes more electric vehicles and more public transport, so emissions have more than halved. This is already an ambitious scenario of energy measures. Now we apply the material-efficiency measures on top, and can see that emissions can be further reduced by around 30%. This assumes a high recycling rate, but an intensification of use of only around 40%. Given a ca. 5% car utilization in Europe, utilization could in principle be intensified much more, so savings could look even greater.
• #24: In China and India, the picture looks quite different. 1) Today, the vehicle emissions are quite low, mainly determined by a very small number of cars per capita in India. 2) In 2050, this number is expected to grow massively, and emissions with it, despite a quite ambitious rate of electrification. 3) Applying material efficiency measures, the emissions from the total car fleet in India and China would still rise – but much less than in the reference scenario. The implication is to design and plan an efficient mobility system in these countries today.
• #25: When looking at the different strategies and their impacts, it is clear that ride-sharing or also called pooling – for example a shuttle model or “uber-pool” type model, would have massive benefits. Using cars from shared fleets for individual rides would also be beneficial, and so would using more need-appropriate vehicle sizes. For individual use, this would mean smaller vehicles, for shared use this would mean lean, comfortable cars optimized for their passenger number. Better recycling and maintenance is important too, and could become more beneficial when more intensive use models require more maintenance and upgrading.
• #26: Overall, in this model, all strategies in both sectors together would reduce G7 emissions by 20Gt, i.e. about 20%. In India and China, this would be 36Gt, about 25%. Given that the ENTIRE carbon budget for G7 countries until 2060 is only 50Gt, these reductions are clearly not enough. Cars alone would emit more that all industries and private consumption can emit together. Therefore, the modelling provides a good insight into the relative effectiveness of the strategies and their interplay with the assumptions made in the reference scenario. For 1.5oC, all Material Efficiency Strategies need to be implemented as fast and extensively as possible. These must be combined with other ambitious measures, such as Deep-energy retrofits of buildings Shift from private to public transport Fast introduction of electric vehicles and clean energy Innovation in low-carbon materials production: Energy efficiency, fuel switch, electrification, CCS