Introduction – This study examines the environmental certification NollCO2, which manages and sets requirements for a building's carbon dioxide emissions during its life cycle. Emissions of carbon dioxide are one of the greenhouse gases that contribute to global warming. This affect opportunities to achieve national and global climate goal. By building according to the requirement of net zero carbon dioxide emissions, the climate impact from the construction sector can be reduced and greenhouse gas emissions in Sweden decrease. Method – The survey is a two-case study of the pilot projects Hyllie Terrass in Malmö and the Lidl store outside Visby, two of the first climate-neutral buildings with NollCO2 certification. The study has a qualitative approach, and the empirical data is collected with the help of semi-structured interviews and an in-depth literature search. Results / Analysis – The results of the study showed that the NollCO2 certification is about reducing carbon dioxide emissions with a focus on the climate issue. Each new NollCO2 project contributes to a reduced amount of carbon dioxide emissions. The certification differs from the other certifications by setting a CO2 budget in line with the climate goal. An obstacle that exists when implementing the NollCO2 certification is that the production cost increases. Meeting the CO2 budget set by Sweden Green Building Council is also a challenge. The certification is completely new in its kind, which created doubts about feasibility and untested methods. There is also a risk when the design work is to be handed over to the construction contract that decisive choices may be affected. Some property owners find that the certification process is lengthy and advanced, due to structural and technical barriers. There can also be problems with profitability for property owners where higher certification ratings outweigh the actual climate impact. There is also criticism that the certification is called zero, as carbon dioxide emissions in practice do not end up at net zero. Sweden is far ahead in the development towards carbon-neutral construction because of the environment and nature being deeply rooted in the culture and history that the country has. The Nordic region has a goal to be the world's most sustainable integrated region by 2030, which will accelerate development. Commitment to building more carbon dioxide-efficient indicates a widespread international interest in the industry for reducing carbon dioxide emissions. Discussion – Based on the study, it is stated that the certification NollCO2 sets requirements for construction projects to build with less climate impact. The certification is the only existing tool to demonstrate a reduced climate impact. It is not possible to achieve zero carbon dioxide emissions today, but the measures of the certification are efforts to achieve the environmental goals. By using and developing the NollCO2 certification, the conditions will be improved. To gain more commitment, more demands are needed from authorities and organizations. There are requirements when it comes to energy, but climate requirements are also needed. If Sweden continues to take the lead, the country will set a good example that can spread knowledge and tools for climate grazing in other countries. Keywords: NollCO2 certification, climate-neutral construction, environmental certification, carbon dioxide emissions, SGBC