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This dataset contains: (1) a time series of lake area extracted from two Landsat-derived datasets (GSWO and GLAD) for ~6 million lakes globally, (2) the annual median lake area of these lakes, calculated separately for each dataset and (3) the monthly median lake area of these lakes, calculated separately for each dataset. For lakes within the northern permafrost zone (i.e., above 50 degrees North and underlain by permafrost), the time series dataset extends 1984-2023. For all other lakes, the time series dataset covers the period 1999-2021. For all lakes, annual median and monthly medians are calculated for the period 1999-2021. 

Climate change is intensifying the fire regime across Siberia, with the potential to alter carbon combustion and post‐fire carbon re‐accumulation trajectories. Few field‐based estimates of fire severity (e.g., carbon combustion and tree mortality) exist in Siberian larch forests (Larixspp.), which limits our ability to project how an intensified fire regime will affect regional and global climate feedbacks. Here, we present field‐based estimates of fire‐induced tree mortality and carbon loss in eastern Siberian larch forests. Our results suggest that fires in this region result in high tree mortality (means of 83% and 76% at Arctic and subarctic sites, respectively). In both absolute and relative terms, aboveground carbon loss following fire is higher in Siberian larch forests than in North America, but belowground carbon loss is considerably lower. This suggests fundamental differences in wildfire behavior and carbon dynamics between dominant vegetation types across the boreal biome. 

Surface water change has been documented across the Arctic due to thawing permafrost and changes in the precipitation/evapotranspiration balance. This dataset uses Moderate Resolution Imaging Spectroradiometer (MODIS) data to track changes in surface water across the region over the past two decades. The superfine water index (SWI) is a unitless global water cover index developed specifically for MODIS data and validated in high northern latitudes. Variation in SWI can also track changes in surface water that occur at the sub-MODIS pixel scale (i.e., changes in water bodies smaller a MODIS pixel, ~500 meters (m)). This dataset (1) maps the average July SWI over pan-Arctic for each year of the MODIS record (2000-2021) and (2) maps the trends in July SWI over 2000-2012 (i.e., Sen's slope of the pixel-wise SWI vs. time). The spatial resolution of this dataset is ~500 m. The yearly SWI files are processed for the entire continuous and discontinuous permafrost zone. The 2000-2021 trend file is processed for lake-rich regions of the Arctic (i.e., lake coverage greater than 5%), as was published in the Webb et al, 2022 paper. The 2000-2022 trend file is processed for the entire continuous and discontinuous permafrost zone. Corresponding publication: Webb, Elizabeth E., Anna K. Liljedahl, Jada A. Cordeiro, Michael M. Loranty, Chandi Witharana, and Jeremy W. Lichstein (2022), Permafrost thaw drives surface water decline across lake-rich regions of the Arctic, Nature Climate Change, doi.org/10.1038/s41558-022-01455-w 

Climate warming is altering the persistence, timing, and distribution of permafrost and snow cover across the terrestrial northern hemisphere. These cryospheric changes have numerous consequences, not least of which are positive climate feedbacks associated with lowered albedo related to declining snow cover, and greenhouse gas emissions from permafrost thaw. Given the large land areas affected, these feedbacks have the potential to impact climate on a global scale. Understanding the magnitudes and rates of changes in permafrost and snow cover is therefore integral for process understanding and quantification of climate change. However, while permafrost and snow cover are largely controlled by climate, their distributions and climate impacts are influenced by numerous interrelated ecosystem processes that also respond to climate and are highly heterogeneous in space and time. In this perspective we highlight ongoing and emerging changes in ecosystem processes that mediate how permafrost and snow cover interact with climate. We focus on larch forests in northeastern Siberia, which are expansive, ecologically unique, and studied less than other Arctic and subarctic regions. Emerging fire regime changes coupled with high ground ice have the potential to foster rapid regional changes in vegetation and permafrost thaw, with important climate feedback implications.