Climate change is one of the most critical issues of our modern world, requiring a shift from fossil fuels to green-energy. Understanding the intricate natural cycling of greenhouse gases is crucial for predicting the impact of current emissions and future changes. The cycling of key greenhouse gases, such as CO2 and methane, involves microorganisms that fix CO2 and release methane, whose roles are poorly understood. Some microorganisms also utilize intermediates like CO and H2 in their metabolism, connecting the cycles of CO2, methane, CO, and H2. Among life's domains, archaea remain enigmatic due to limited genomic information and challenges in culturing them. Anaerobic haloarchaea, which thrive in high-salt, anoxic environments - mostly deep-sea hypersaline anoxic basins, are particularly intriguing. Their metabolic strategies, potentially involving specialized enzyme complexes, hold the key to understanding gas production and consumption, impacting our grasp of biogeochemical cycles, global warming, and climate change. Additionally, anaerobic archaea offer biotechnological promise in waste biomass anaerobic digestion for biofuel production as well as discovery of new enzymes and metabolic pathways.