Carbon dioxide and methane emissions are the two primary anthropogenic climate-forcing agents and an important source of uncertainty in the global carbon budget. Uncertainties are further magnified when emissions occur at fine spatial scales (<1 km), making attribution challenging. We present the first observations from NASA’s Earth Surface Mineral Dust Source Investigation (EMIT) imaging spectrometer showing quantification and attribution of fine-scale methane (0.3 to 73 tonnes CH ₄ hour ⁻¹ ) and carbon dioxide sources (1571 to 3511 tonnes CO ₂ hour ⁻¹ ) spanning the oil and gas, waste, and energy sectors. For selected countries observed during the first 30 days of EMIT operations, methane emissions varied at a regional scale, with the largest total emissions observed for Turkmenistan (731 ± 148 tonnes CH ₄ hour ⁻¹ ). These results highlight the contributions of current and planned point source imagers in closing global carbon budgets.

Small water bodies (i.e., ponds; 0.01 km ² ). We leverage high‐resolution (3 m) optical satellite imagery from Planet Labs and deep learning methods to map seasonal changes in pond and lake areal extent across four regions in Alaska. Our water maps indicate that changes in open water extent over the snow‐free season are especially pronounced in ponds. To investigate potential impacts of seasonal changes in pond area on carbon emissions, we provide a case study of open water methane emission budgets using the new water maps. Our approach has widespread applications for water resources, habitat and land cover change assessments, wildlife management, risk assessments, and other biogeochemical modeling efforts.

Methane (CH₄) emissions from thawing permafrost amplify a climate warming feedback. However, upscaling of site‐level CH₄ observations across diverse Arctic landscapes remains highly uncertain, compromising accuracy of current pan‐Arctic CH₄ budgets and confidence in model forecasts. We report a 30,000‐km² survey at 25‐m² resolution (~1 billion observations) of CH₄ hotspot patterns across Alaska and northwestern Canada using airborne imaging spectroscopy. Hotspots covered 0.2% of the surveyed area, concentrated in the wetland‐upland ecotone, and followed a two‐component power law as a function of distance from standing water. Hotspots decreased sharply over the first 40 m from standing water (y = 0.21×^−0.649, R² = 0.97), mirroring in situ flux observations. Beyond 40 m, CH₄ hotspots diminished gradually over hundreds of meters (y = 0.004×^−0.164, R² = 0.99). This emergent property quantifies the distribution of strong methanogenic zones from site to regional scales, vastly improving metrics for scaling ground‐based CH₄ inventories and validation of land models.

Methane (CH₄) emissions from climate‐sensitive ecosystems within the northern permafrost region represent a potentially large but highly uncertain source, with current estimates spanning a factor of seven (11–75 Tg CH₄ yr⁻¹). Accelerating permafrost thaw threatens significant increases in pan‐Arctic CH₄ emissions, amplifying the permafrost carbon feedback. We used airborne imaging spectroscopy with meter‐scale spatial resolution and broad coverage to identify a previously undiscovered CH₄ emission hotspot adjacent to a thermokarst lake in interior Alaska. Hotspot emissions were confined to <1% of the 10 ha lake study area. Ground‐based chamber measurements confirmed average daily fluxes from the hotspot of 1,170 mg CH₄ m⁻² d⁻¹, with extreme daily maxima up to 24,200 mg CH₄ m⁻² d⁻¹. Ground‐based geophysical measurements revealed thawed permafrost directly beneath the CH₄ hotspot, extending to a depth of ∼15 m, indicating that the intense CH₄ emissions likely originated from recently thawed permafrost. Hotspot emissions accounted for ∼40% of total diffusive CH₄ emissions from the lake study site. Combining study site findings with hotspot statistics from our 70,000 km² airborne survey across Alaska and northwestern Canada, we estimate that pan‐Arctic terrestrial thermokarst hotspots currently emit 1.1 (0.1–5.2) Tg CH₄ yr⁻¹, or roughly 4% of the annual pan‐Arctic wetland budget from just 0.01% of the northern permafrost land area. Our results suggest that significant proportions of pan‐Arctic CH₄ emissions originate from disproportionately small areas of previously undetermined thermokarst emissions hotspots, and that pan‐Arctic CH₄ emissions may increase non‐linearly as thermokarst processes increase under a warming climate.

Purpose of Review: We review how ‘abrupt thaw’ has been used in published studies, compare these definitions to abrupt processes in other Earth science disciplines, and provide a definitive framework for how abrupt thaw should be used in the context of permafrost science. Recent Findings: We address several aspects of permafrost systems necessary for abrupt thaw to occur and propose a framework for classifying permafrost processes as abrupt thaw in the future. Based on a literature review and our collective expertise, we propose that abrupt thaw refers to thaw processes that lead to a substantial persistent environmental change within a few decades. Abrupt thaw typically occurs in ice-rich permafrost but may be initiated in ice-poor permafrost by external factors such as hydrologic change (i.e., increased streamflow, soil moisture fluctuations, altered groundwater recharge) or wildfire. Summary: Permafrost thaw alters greenhouse gas emissions, soil and vegetation properties, and hydrologic flow, threatening infrastructure and the cultures and livelihoods of northern communities. The term ‘abrupt thaw’ has emerged in scientific discourse over the past two decades to differentiate processes that rapidly impact large depths of permafrost, such as thermokarst, from more gradual, top-down thaw processes that impact centimeters of near-surface permafrost over years to decades. However, there has been no formal definition for abrupt thaw and its use in the scientific literature has varied considerably. Our standardized definition of abrupt thaw offers a path forward to better understand drivers and patterns of abrupt thaw and its consequences for global greenhouse gas budgets, impacts to infrastructure and land-use, and Arctic policy- and decision-making.