The first priority of our three-pronged approach to achieve net-zero emissions is to reduce our energy use and emissions through operational efficiency initiatives.
Tiffany operates manufacturing operations, including diamond cutting and polishing workshops, in addition to our retail stores, offices and distribution facilities, which enables us to directly reduce our emissions connected to our core business through energy efficiency projects.
We seek high-impact efficiency improvements when we build new facilities and renovate existing ones. In 2018 and 2019, we earned LEED (Leadership in Energy and Environmental Design) certification for five new retail locations in China. By upgrading our retail lighting to LED systems at existing stores, we are able to reduce energy use by an average of 20% year over year. All new retail stores are equipped with LED systems and in 2018, we converted lights at 13 of our retail locations. We are also improving efficiency by incorporating more efficient heating and cooling systems, installing building energy-management systems and upgrading to energy-efficient computers and office equipment. At our New York flagship store, we have installed a modern building energy-management system, which optimizes performance of heating and cooling components such as motors, fans and pumps. In 2019, as we begin renovations to the New York flagship store, we intend to incorporate additional ways to minimize our environmental footprint.
Separate from our purchases of renewable electricity, we held global greenhouse gas emissions flat between 2013 and 2018, even as our global operations grew. By being more energy efficient, we reduced our emissions per square foot by 10% over the same period. We are also taking steps to better understand our carbon footprint outside our direct operations (Scope 3 emissions), including from sourcing, transportation and third-party manufacturing. In 2018, we completed a baseline assessment of our Scope 3 emissions and the next step will be to identify and encourage reductions in accordance with those results.