Hydroponic systems produce plants in a soilless environment requiring mineral fertilizers to meet plant nutritional needs, whereas aquaponics combines an aquaculture production system with hydroponics, where fish waste provides nitrogen, phosphorous and potassium for plant growth and nitrifying and mineralising bacteria act as filters . The relative environmental impact of hydroponic systems is lower com- pared with conventional systems owing to the significant reductions in land use and fertilizer usage  . While studies indicate that aquaponics and hydroponics have higher yields and a lower environmental footprint than conventional agriculture , aquaculture and heated greenhouse production , aquaponic production may need to be coupled or decoupled or have double-recirculation systems to meet the different requirements of farmed fish and crop species . Aquaponics and hy- droponics are a promising adaptation option for urban agriculture, with benefits including a protected growing environment from climate ex- tremes, reduced GHG emissions related to food transportation, reduced food waste, rainwater harvesting and use of food waste  . Such systems show promise for reducing food production environmental footprints and increasing food security, particularly in arid or water-stressed environments . Barriers to aquaponics and hydro- ponics adoption include market acceptance of cultured fish species and desirability of plant crops, lack of expertise, legal constraints or high investment costs and financial feasibility . There is high confidence  that a major barrier to hydroponic and aquaponics adoption is the re- quirement for skilled operators , which could be mitigated by decoupling systems and disciplines . As yet, these systems are not widely implemented and information on their climate change impacts is limited.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report