Mitigation Although climate change adaptation is central to safeguard the human rights to safe drinking water and sanitation, the ‘hydrological transition’ as advocated by the Special Rapporteur, also shines a light on the human rights impacts of climate mitigation strategies. Some low-carbon energy generation methods, such as negative emission biofuels or dams, are being suggested as ‘green’ solutions. These methods can have, however, massive impacts on human rights generally, and the human rights to safe drinking water and sanitation in particular. In order to find ‘green’ solutions without compromising human rights, the human rights to safe drinking water and sanitation must be reintegrated into conversations about climate mitigation. The carbon-impact of water and sanitation The hydrological transpiration addresses the need to adapt safe drinking water and sanitation services and management to a changing climate while respecting natural hydrology and ecology as well as human rights. It also draws attention to safe drinking water and sanitation services and facilities through the lens of mitigation, in order to recentre the human rights to safe drinking water and sanitation in conversations around reducing greenhouse gas emissions and limiting the extent of climate change. Safe drinking water and sanitation services, and in particular wastewater sanitation systems, can generate significant greenhouse-gas emissions. The combined emissions of water supply and sanitation services (electricity consumption and breakdown processes) are expected to grow as populations grow. It is therefore crucial to design wastewater remediation strategies and models that limit the growth of emissions from the sanitation sector. In regions where groundwater becomes depleted or unreliable, alternative sources of freshwater may need to be found. In order to become drinkable and safe, these sources may have larger energy needs than traditional sources. One such source is desalinated seawater. Although reverse osmosis technologies have reduced the energy cost of desalination, while conventional water treatment requires 0.2–0.4 kWh m3, desalination needs between 3.5 and 4.5 kWh m3 to produce drinking water - this can augment greenhouse gas emissions from the water sector. While alternative methods for providing safe drinking water will become increasingly important with the impacts of climate change, must go hand in hand with sustainable adaptation processes. The hydrological transition reinforces social and environmental resilience through nature-based solutions and sustainable water and sanitation services and offers us a way to limit emissions. For example, energy recovery from wastewater systems could provide over 55 per cent of the electricity required for municipal wastewater treatment by 2040, demonstrating the dual benefits of reducing waste-related emissions and producing renewable energy. As another example, wetlands accommodate the largest carbon stocks among terrestrial ecosystems, storing twice as much carbon as forests. Taking into account that wetlands also reduce risks derived from floods and droughts, purify drinking water, and foster healthy biodiversity, their restoration and conservation is of critical importance in both adaptation and mitigation strategies in order to protect the human rights to safe drinking water and sanitation. 5