Fig. 1

Carbon intensity of proposed Amazon hydropower dams. A total of 351 dams (>1 MW) have been proposed in five different countries of the Amazon basin, 65% in elevations below 500 m a.s.l. (lowland) and 35% above 500 m a.s.l. (upland) (a). b Cumulative frequency of lowland (< 500 m a.s.l.) and upland (> 500 m a.s.l.) dams proposed for the Amazon basin with respect to predicted carbon intensities over 20- and 100-year time horizons. c Carbon intensities of proposed dams (100-year time horizon) plotted against elevation above sea level. Point colors correspond to the countries where each dam is located. Green dashed lines (80 kg CO₂eq MWh⁻¹) indicate the projected carbon intensity of the global electricity sector in 2040 based on a scenario consistent with the UN 2030 Agenda for Sustainable Development²³. The ranges of carbon intensities of coal- and natural gas-fired power plants reported by the IPCC are shown in the purple and orange areas, respectively, with medians indicated by horizontal dashed lines⁷