This paper presents a greenhouse-gas (GHG) emission reduction toolkit at an urban scale as a response to climate change local effects. Studies show that the most considerable amount of GHG emitted from cities worldwide; as the result of fossil fuel combustion, energy consumption, and other human functions. However, not the equivalent CO2 absorbers are embedded in cities, nor the mitigation strategies. Urban areas are where the GHG emission causes and the solutions cross and are the best laboratories to examine the new initiatives. This toolkit was developed to reflect this significant necessity of the urban environment to gather, present, and weigh the possible approaches toward a lower-carbon city. The four main contributors to GHG emission, including Energy Management, Transportation, Waste Management, and Urban Land Use, were identified, and their associated mitigation techniques were proposed. They were also weighted based on their abatement potentials, and the recommended implementation policies were linked to them. The techniques were chosen over a comprehensive literature review from the available databases from 2000 to 2020. In the end, the critical challenges in the implementation phases, and some strategic suggestions were proposed to facilitate the process.