Background The rise in the Earth's average surface temperature caused by human activities, reported by the Intergovernmental Panel on Climate Change (IPCC), seriously impairs the process of sustainable development established by the EU Conference in Gothenburg. To respond to this challenge, the European Commission set strict targets for greenhouse gas (GHG) reductions. In 2007 the EU adopted an energy policy for Europe, going beyond targets set by the Kyoto Protocol. The 2007 EU Green Paper ‘Adapting to climate change in Europe - options for EU action’ demonstrated that adaptation actions have become an unavoidable and indispensable complement to mitigation actions. In order to reach national targets, all levels of society must participate, including individual citizens. In this sense, the role played by local authorities is essential, since they are the key intermediary between the local community and decision-makers in central government. Objectives The main objective of the LAKS project was to demonstrate that local authorities can contribute to the achievement of national and EU environmental goals by creating specific local accountability, management systems, and mitigation and adaptation actions for GHG reductions. The project worked to enhance knowledge, skills and awareness at the political level, of the potential of local action to contribute to climate change mitigation. A process of developing local responsibility was started, through the definition of targets and the implementation of a monitoring, reporting and evaluation system. In this context, the LAKS project aimed to support four cities on a long-term basis to significantly reduce GHG emissions, including the increase of the local authorities’ capacity for planning, managing and reporting their commitments. Results The LAKS project developed a local system for greenhouse gas (GHG) accountability consisting of a series of tools and methodologies. The project actions were implemented in four cities of medium size, in Italy (Reggio Emilia and Padova), Spain (Girona) and Poland (Bydgoszcz), in order to define a simple-to-implement and standard system that could potentially be used all over Europe. The project beneficiary conducted an international review of tools and methods, focusing on GHG emissions. Two projects then developed a Local Government GHG Emissions Inventory Manual to provide non-expert municipality staff with comprehensive advice and instructions for using the LAKS Emissions Inventory Tool. The manual and tool cover emissions from the public and private sectors (e.g. energy, agricultural, waste) and household emissions. These were used in each of the four case study cities. Actions were identified for Mitigation and Adaptation Local Plans in the four cities, and a reporting system was designed. The project’s Road Map described the steps needed to implement these plans. Information and data published in GHG Emission Reports formed the basis for the development of mitigation and adaptation plans in the four cities, which were subsequently approved by all the partner municipalities. An Excel tool was developed for assessing the economic impact of present and potential policies and measures, which helped identify measures for the local plans. The project also produced a model for mitigation and adaptation when the system is replicated elsewhere. Another project outcome was a Model for Climate Balances. This is structured into two main parts: the first sums up the outcome of the monitoring of a Mitigation and Adaptation Local Plan's state of progress, and the second reports on the GHG emissions. In Reggio-Emilia, the Mitigation and Adaptation Plan encompassed smart city services, sustainable mobility, renewable energy, green areas, and the low carbon economy. Key actions involved capacity building and increasing company involvement in adaptation and mitigation activities, through training courses that particularly focused on utility companies. The other cities took a similar approach. Networking and twining activities were organised between the cities. The project developed a questionnaire to assess how the system for GHG accountability had performed in the four municipalities. On the basis of the answers, the system was revised. The project produced final guidelines, taking into account the questionnaire. These give a step-by-step guide to implementing the phases for developing a climate analysis; namely, they explain how to identify the sectors to be investigated, select a baseline year for the analysis, find data sources, and use the LAKS Emissions Inventory Tool in the local actions. Some modifications may be necessary, to be assessed on a case-by-case basis. The LAKS system should bring environmental benefits in terms of direct emissions reductions. The project also demonstrated that its actions in the four cities increased awareness at the political and technical levels of relevant local initiatives, particularly focused on the integration of mitigation and adaptation actions. The project contributes to helping achieve European GHG reduction targets at the local level and, in particular, contributes to achieving EU 20-20-20 targets for reducing emissions, reducing energy use through energy efficiency, and increasing the use of renewable energy. The main innovative aspect of the project was the development of a system that enables small and medium sized municipalities to calculate their CO2 emissions and to identify appropriate strategies to diminish them. This represents one of the first developed systems for accountability of GHGs emissions focused on local authorities, with a high demonstration value. In terms of socio-economic benefits, the adoption of the project’s system should allow savings due to a decrease in fuel use, and generally in terms of energy consumption. The project has made its easy-to-use tools widely available. This makes it possible to replicate the project in other municipalities, a goal furthered by the beneficiaries being part of an international network working with the same aim: the Covenant of Mayors.