世界经济论坛-建筑环境中的循环性_在改造中释放机会（英）-2025.1_30页_4mb

Summary of "Circularity in the Built Environment: Unlocking Opportunities in Retrofits"

Core Content

This white paper explores the role of circularity in retrofitting as a key strategy for achieving sustainability and decarbonization in the built environment. It outlines the growth of the retrofit market, the importance of materials in retrofit costs, and the potential for circular practices to reduce environmental impact and enhance economic value.

Main Points

1. The Retrofit Market and Its Growth

• The global retrofit market is expected to grow significantly, reaching $3.9 trillion by 2050, up from $500 billion today.
• Retrofitting is projected to grow at 8% annually from 2024 to 2050, outpacing the overall construction market growth of 4%.
• IEA net-zero targets require 20% of existing building stock to be zero-carbon ready by 2030, 50% by 2040, and over 85% by 2050.

2. Retrofitting and Decarbonization

• Retrofitting can reduce total carbon emissions by 50–75% compared to new construction.
• Embodied carbon (carbon emissions from material extraction and manufacturing) accounts for up to 50% of a building's life cycle emissions.
• Retrofitting helps in reducing operational emissions and minimizing resource extraction.

3. Materials in Retrofitting

• Materials are the largest cost component in retrofitting, accounting for 60% of total costs.
• By 2050, the retrofit materials market is expected to reach $2.3 trillion.
• Key materials for retrofitting include glass, steel, concrete, aluminium, brick and plastic (by weight), and fiberglass, mineral wool, foam board and spray foam (by volume).
• Smart surfaces can improve building efficiency by reflecting more sunlight and reducing energy use.

4. Circular Retrofitting

• Circular retrofitting involves retaining, reusing, recycling and repurposing materials to minimize virgin resource extraction and reduce waste.
• The paper estimates that 50% of materials removed during retrofits could be recirculated in the value chain from 2023 to 2050.
• This would result in an annual reduction of 200 million metric tonnes of CO₂e by 2030 and 500 million metric tonnes by 2050.

5. Economic and Environmental Benefits

• Circular retrofits can be financially neutral or positive, especially with service-based models and horizontal/vertical integration.
• They can stimulate local economies by creating over 2 million new jobs and 141 million job years in North America and Europe alone.
• Circular practices reduce logistics costs, waste generation and landfill use, while increasing material efficiency.

Key Information

Material Demand and Recirculation

• Total materials required for global retrofits from 2023 to 2050: 40 billion tonnes.
• Asia-Pacific will require the largest volume of materials (around 25 billion tonnes), followed by Europe (around 5 billion tonnes).
• Aluminium is expected to have the highest recirculation rate (around 95%), while plastics, concrete and gypsum board may have lower rates due to sorting challenges and downcycling limitations.

Regional Analysis

• Europe is the most advanced in circular retrofitting due to mature circular design principles, advanced take-back systems and specialized training.
• North America has established incentive programs (e.g., RetrofitNY) and reverse logistics initiatives, but lacks a consistent end-of-life waste payment system.
• Asia-Pacific is rapidly improving its logistics and design practices (e.g., China's circular economy zones, Japan's modular construction).
• Latin America and Africa are at the lower end of circular retrofitting adoption, with fragmented supply chains and limited financial incentives.
• Middle East has initiatives for landfill diversion and the UAE's Circular Economy Council, but lacks mandatory waste segregation and international waste cost alignment.

Implementation Challenges

• Retrofitting requires careful dismantling to salvage reusable components, which is time-consuming but more sustainable than traditional demolition.
• Digital tools such as materials passports and digital twins are critical for transparency and material lifecycle tracking.
• Regulatory frameworks and financial mechanisms (e.g., tax exemptions, decarbonization subsidies) are essential for scaling circular retrofits.

Conclusion

• Circular retrofitting is a vital submarket for achieving global sustainability and decarbonization goals.
• It offers economic opportunities and environmental benefits, including job creation, cost savings, and reduced CO₂ emissions.
• To ensure long-term sustainability, stakeholders must establish circular value chains now, focusing on material sourcing, reuse infrastructure, and professional capabilities.
• A comprehensive systems approach is necessary to scale circular practices, and geographical variations require tailored strategies for effective implementation.