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ABSTRACT Climate change and extreme weather events affect hydrology and water resources in catchments worldwide. This study analysed Blue Water (BW) and Green Water (GW) scarcity in the McKenzie Creek watershed in Ontario, Canada, and explored how changes in temperature and precipitation may impact water scarcity dynamics. The McKenzie Creek is the main water source for agricultural activities for the Six Nations of the Grand River reserve (the largest Indigenous community in Canada) and other non‐Indigenous communities in the watershed. Data from the water use surveys and streamflow simulations performed using the Coupled Groundwater and Surface‐Water Flow Model (GSFLOW) under the Intergovernmental Panel on Climate Change (IPCC) Representative Concentration Pathways (RCP) scenarios 4.5 and 8.5, representing moderate and high greenhouse gas emissions and climate warming, respectively, were used to calculateBWandGWscarcity. Study results showed thatBWscarcity may increase to ‘moderate’ levels if water users extract the maximum permitted water withdrawal allocation. This level of scarcity has the potential to cause ecological degradation and water quality issues in the watershed.GWscarcity will steadily increase throughout the 21st century due to climate warming with the western portion of the McKenzie Creek watershed projected to experience slightly higher levels ofGWscarcity. This may cause users to withdraw more water resources, thereby decreasingBWavailable for downstream communities, including the Six Nations of the Grand River. This study provides water resource managers and regional planners with important information about potential challenges facing the watershed due to increased water use and changing climate conditions. 

Non-technical summary We summarize some of the past year's most important findings within climate change-related research. New research has improved our understanding of Earth's sensitivity to carbon dioxide, finds that permafrost thaw could release more carbon emissions than expected and that the uptake of carbon in tropical ecosystems is weakening. Adverse impacts on human society include increasing water shortages and impacts on mental health. Options for solutions emerge from rethinking economic models, rights-based litigation, strengthened governance systems and a new social contract. The disruption caused by COVID-19 could be seized as an opportunity for positive change, directing economic stimulus towards sustainable investments. Technical summary A synthesis is made of ten fields within climate science where there have been significant advances since mid-2019, through an expert elicitation process with broad disciplinary scope. Findings include: (1) a better understanding of equilibrium climate sensitivity; (2) abrupt thaw as an accelerator of carbon release from permafrost; (3) changes to global and regional land carbon sinks; (4) impacts of climate change on water crises, including equity perspectives; (5) adverse effects on mental health from climate change; (6) immediate effects on climate of the COVID-19 pandemic and requirements for recovery packages to deliver on the Paris Agreement; (7) suggested long-term changes to governance and a social contract to address climate change, learning from the current pandemic, (8) updated positive cost–benefit ratio and new perspectives on the potential for green growth in the short- and long-term perspective; (9) urban electrification as a strategy to move towards low-carbon energy systems and (10) rights-based litigation as an increasingly important method to address climate change, with recent clarifications on the legal standing and representation of future generations. Social media summary Stronger permafrost thaw, COVID-19 effects and growing mental health impacts among highlights of latest climate science.