The widespread adoption of cloud computing is having a big impact on the environment since the energy consumption of data centers and the resulting emissions are significantly increasing. Researchers and practitioners in this field are looking for methods to improve the energy efficiency of data centers and increase the use of green energy sources. In fact, besides the energy consumption, the greenness of a data center can be characterized by the quantity of CO 2 emissions associated to the use of electricity (from a specific energy mix) and/or fuels (e.g. for heating or cooling). In this paper, we propose an approach in which environmental impacts are considered as an important factor for the selection of the cloud site for the deployment of applications. In detail, considering a user perspective and focusing on the assessment of energy consumption and CO 2 emissions, this paper proposes a method to support the users towards greener choices in the deployment of cloud applications.