The current and future warming of Lake Titicaca

Water temperature plays an important role in physical and biogeochemical processes within lakes, as well as being a key indicator of the impact of climate change on the water body. Thus, analysing lake surface water temperature (LSWT) is essential for comprehending how a lake responds to climate warming. Lake Titicaca, the largest lake in South America, is a critically important water resource in Peru-Bolivia; however, it is also one of the most impacted by climate change. To assess historical and future variability, we analyse LSWT patterns of Lake Titicaca using the Global LAke Surface water Temperature (GLAST) dataset (1981–2020, 2021–2099), and the daily satellite-derived European Space Agency Climate Change Initiative (ESA CCI) Lakes dataset (2000–2020) for validation. Our analysis suggests that: (1) there has been an annual warming trend of + 0.15 K decade -1 in Lake Titicaca over the past 40 years, driven by shortwave radiation and air temperature; and (2) the future warming of Lake Titicaca will vary under different Representative Concentration Pathway (RCP) scenarios, between + 0.02 K decade -1 (RCP 2.6), +0.23 K decade -1 (RCP 6.0), and + 0.44 K decade -1 (RCP 8.5). Additionally, under RCP 8.5, the average intensity of lake heatwaves is projected to increase from 0.5 K (1981–2020) to 3.3 K (2080–2099), with their average duration increasing from 22 days to 365 days. This research provides a comprehensive understanding of LSWT in Lake Titicaca under past and future climatic warming. Our findings will provide valuable information for practitioners and policymakers in tackling the effects of climate change on Lake Titicaca.