There is now widespread recognition in the international community that the commitments made by national governments under the Paris Climate Agreement in 2015 cannot be achieved without concerted action by cities. Fortunately, many mayors have shown strong commitment to tackling climate change and a willingness to collaborate to achieve this goal. C40 Cities, a network of mayors of the world’s megacities committed to addressing climate change, responded to the Paris Agreement by publishing an analysis — Deadline 2020 —of the emission reduction pathway their cities would need to achieve to play their part in keeping global average temperature rise within “safe” limits (below 1.5°C). As individual C40 cities now increase the ambition of their climate plans accordingly, this report takes that work a stage further by analyzing the biggest opportunities for cities to accelerate the reduction of their carbon emissions.
While the technologies and expertise exist to limit the temperature increase to 1.5°C, the challenge is still formidable. With cities already stretched to meet multiple competing priorities, city leaders must determine the critical actions that can change their current emissions trajectory and work proactively with their stakeholders to build and invest in the infrastructure and incentives needed to make significant progress toward those actions. That means prioritizing action around initiatives that catalyze systemic change. For this report, C40 has partnered with The McKinsey Center for Business and Environment to quantitatively assess the biggest opportunities for emissions reduction and what they will mean for different types of cities around the world.
Cities can significantly reduce their carbon emissions by addressing not only the efficiency of appliances and equipment in buildings but also the efficiency of commercial and residential buildings themselves, including both high-rise and low-rise structures. Across all opportunities, cities will benefit from improving the availability of building energy data as a key enabling action to well-informed code or equipment changes. Our analysis indicates that many cities can reduce about 20 to 55 percent of the total gap in their emissions abatement targets by improving how buildings consume energy, not including additional opportunities in appliances.
Focused acceleration of energy efficiency in municipal, commercial, and residential buildings would require significant up-front investments: around $20 to $100 per metric ton of CO2 equivalent, translating to tens of billions of dollars in capital required through 2030 for a single city. But it also makes economic sense: packaged together, investments in more energy efficient buildings can generally be recouped through energy savings in 5 to 15 years for most cities, while continuing to reduce energy costs—as well as providing more resilient, comfortable spaces to live, work, and play—for city residents through 2050 and beyond.
Chapter 2.2 lists the strategies of optimizing energy efficiency in buildings:
•Raise energy efficiency standards for new builds.
•Accelerate retrofits of existing building envelopes.
•Upgrade HVAC and water heating systems to low-carbon technologies.
•Shift lighting to LEDs.
•Expand use of building automation and controls.
The analysis of the emissions reduction potential in buildings is based on renovation and upgrade rates that leading cities are on track to achieve by 2030 through such coordinated, at-scale programs. Future policy should consider:
•Bypass natural renovation cycles.
•Push for higher efficiency and phase out of fossil fuel HVAC.