In response to growing concerns over climate change, many commercial real estate building owners and managers are attempting to step up and do what it takes to achieve not just “green” objectives, but to reach overall ESG goals as well.

There’s a good reason for this action. Real estate accounts for close to 40% of the total global carbon emissions, while energy accounts for 20% to 40% of a building’s annual operating costs.

The problem, however, is that many aren’t sure how to exactly do this. Or, as JLL put it in its “Real Estate Leader’s Guide to Decarbonizing Your Portfolio: “What’s missing is a common understanding of how to successfully measure and reduce carbon emissions within the built environment.”

The built environment describes the “man-made or modified structures that provide people with living, working and recreational spaces,” according to the United States Environmental Protection Agency. And according to Architecture 2030, concrete, steel and aluminum is responsible for 23% of all global emissions.

This suggests that one solution to the problem is to reduce carbon by doing a better job of design, specifications and material selection. But what if your building is already—built? The JLL “Real Estate Leader’s Guide” offers solutions, starting with the following steps:

1. Baseline portfolio emissions. With this initial step, owners and managers should measure how and when carbon is emitted through scopes offered by the Greenhouse Gas (GHG) protocol. “Correctly categorizing your emissions into scope levels will give you an accurate assessment of your organization’s carbon footprint,” the report said. But it can take time.

2. Benchmark your data. Comparing your metrics against others in your industry can help determine current standards, and where to focus your efforts. Where to find that information? JLL recommends CDP, a non-profit disclosure system. as a place to start.

3. Find a framework for success. The framework can be based on what others use and what stakeholders will support. JLL suggests the United Nation’s Sustainable Development Goals as a place to start.

4. Set up a central data base to track and compare data. Doing so helps measure initial carbon emissions and potential improvements over time. JLL uses Canopy, a proprietary platform that measures, manages and reports on sustainability performance.

5. Continually refine KPIs. Once building owners and managers obtain data, it’s possible to take action. And once action is taken, goals might change, pushing carbon reduction efforts even higher.