Coal is the central energy resource in Poland, and air pollution levels in cities in Poland are some of the highest in Europe. Environmental protection problems are among the greatest challenges for the Polish authorities and society. As of today, there is a risk of temperatures rising 1.5 °C before 2050; this rise in temperature is leading to the intensification of changes that are unfavorable for people, such as weather disasters. The aim of this article was to analyze the scale of necessary sustainable investments of the local governments in Poland, with particular emphases on the role of cities, the current structural gaps and the financial mismatches. The focus was mainly on the adaptation and mitigation aspects of climate change, with less emphasis on social factors. The results indicated an increasing need for green and/or sustainable investments by local governments. A number of barriers to accessing new forms of sustainable finance were identified. The most important hurdles included low involvement of the private sector in local government financing, regulatory and fiscal barriers, and the inability of local governments to provide effective currency hedging. The need for new mechanisms to help local governments through guarantees or innovative instruments and potentially through new institutions or facilities was demonstrated.