This thesis examines investment characteristics of emerging emission allowance markets, which are created under special mandatory regimes – emissions trading systems (ETSs). As a relatively new class of assets emission allowances can potentially provide many opportunities for diversification, hedging, and enhanced returns in the context of global climate policy responses. Using a broad secondary literature analysis, the thesis shows that the four emission allowance markets, where participation of financial investors is permitted, have stabilized over the recent years and can generally be considered investable in terms of liquidity, size, product standardization, price transparency, and credibility of market infrastructure. Nevertheless, investors need to pursue a balanced approach as the markets remain highly susceptible to regulatory changes, which can significantly impact the risk-return profile of emission allowances.