About

Greg Asner is the director of ASU's Center for Global Discovery and Conservation Science and serves as a professor based in Hawaii. He oversees ASU's science activities and is primarily affiliated with the School of Ocean Futures, with a secondary affiliation to the School of Geographical Sciences and Urban Planning. Dr. Asner is an ecologist recognized for his exploratory and applied research on land and ocean ecosystems at regional to global scales. He has published hundreds of scientific articles and has participated in numerous national and international programs with NASA, the U.S. State Department, and the United Nations. His research interests include land use, biodiversity, coral reefs, climate change, remote sensing, and communities, particularly in Hawaii. He has received multiple scientific and sustainability awards and is an elected member of the U.S. National Academy of Sciences.

Research topics

• Environmental science
• Biology
• Ecology
• Geography
• Geology
• Agroforestry
• Environmental resource management
• Mathematics
• Atmospheric sciences
• Political Science
• Paleontology
• Forestry
• Chemistry
• Economics
• Oceanography
• Environmental health
• Climatology
• Natural resource economics
• Medicine
• Agronomy
• Meteorology
• Physical geography

Selected publications

• Global 10-meter seagrass maps

  Open MIND · 2026-02-14

  datasetSenior author

  This dataset provides the first spatially consistent, global-scale seagrass extent maps at 10-meter resolution, designed to support coastal conservation planning, ecosystem monitoring, and blue carbon assessments. The maps capture global shallow-water seagrass distribution for two time periods: 2019–2020 and 2023–2024, enabling analysis of spatial patterns, persistence, and change over time. Seagrass extent is provided as GeoTIFF raster files at native 10-m spatial resolution, compatible with standard GIS and remote-sensing platforms. The dataset is optimized for integration into conservation workflows, national greenhouse gas inventories, restoration prioritization, and large-scale ecological analyses.

  DOI

• Duration of super-emitting oil and gas methane sources

  Nature Communications · 2026-01-24 · 1 citations

  articleOpen access

  The duration of super-emitting events (>100 kg h-1) in oil and gas basins remains insufficiently understood but is key for reporting programs and mitigation strategies. Carbon Mapper conducted aerial surveys from April 30 to May 17, 2024, over the New Mexico Permian Basin, covering 276,000 wells, 1100 compressor stations, 175 gas processing plants, and 27,000 km of pipeline. We find over 500 super-emitting sources with 300 of these sources observed repeatedly across multiple days. We quantify total super emissions by integrating individual events with observationally constrained event durations (5.98 −14.7 Gg CH4) and compare to total emissions derived from basin average snapshots (12.7 ± 0.92 Gg CH4). This gap between emission estimates is reconciled through assumptions on missed detections, characteristic event duration, detection frequency, and diurnal variability. Emission events generally lasted for at least 2 hours, and a small subset of sources (18 total), persistently emitted throughout the entire campaign, representing a near-term opportunity for mitigation. When compared to regional flux estimates derived from independent observations, we estimate super-emitters to contribute approximately 50% (37-73%) towards total emissions. Frequent wide-area monitoring is crucial for capturing rare super-emitter events that, together with other emission sources, drive basin-level variability and emission intensity. Aerial surveys over the Permian Basin found 500+ major methane leaks, many recurring. A few sites leaked continuously and offer quick mitigation wins. These super-emitters may produce ~50% of regional emissions, underscoring the need for frequent monitoring.

  PublisherOA PDFDOI

• Mapping Live Coral: Comparing Spaceborne to Airborne Imaging Spectroscopy

  Remote Sensing · 2026-01-29 · 1 citations

  articleOpen access1st authorCorresponding

  Live coral cover is a key indicator of coral reef composition, health, and functioning. Airborne imaging spectroscopy provides verifiably accurate estimates of live coral cover to seawater depths of 25 m, yet satellite-based approaches have not achieved the same level of performance. The new Tanager-1 satellite carries a high-fidelity imaging spectrometer in sun-synchronous Earth orbit, providing an opportunity to transition from airborne to spaceborne imaging of live corals and other benthic constituents. We coordinated overpasses of Tanager-1 and Global Airborne Observatory (GAO) imaging spectrometer measurements of coral reef to a depth of 25 m in Hawaiʻi. Tanager-1 has a spatial resolution of 30 m, while the GAO data were collected at 2 m resolution, requiring detailed modeling to simulate 30 m data for subsequent comparison to the satellite data. At 30 m resolution, the two sensors generated similar geographic patterns of live coral, macroalgal, and sand cover. Field validation indicated similar precision and accuracy of live coral cover estimates, and the ratio of live coral to macroalgal cover proved similar between sensors. Overall results indicate that live coral cover can be mapped with high-fidelity imaging spectroscopy from Earth orbit. With the advent of more spaceborne imaging spectrometers, a new era of live coral monitoring will be possible, filling a critical gap for repeated assessments of reef compositional change at a global level.

  PublisherDOI

• Consistent Spectral Reflectance Signatures of Photosystem II Thermal Tolerance (T _crit ) in Contrasting Foundation Tree Species

  Journal of Geophysical Research Biogeosciences · 2026-02-27

  article

  Abstract Photosystem II (PSII) is among the most thermally sensitive components of photosynthesis, and emerging evidence suggests that plants in diverse biomes face an increasing risk of PSII damage under future climate change. However, uncertainties in the distribution and drivers of PSII thermal tolerance (T crit ) limit our ability to predict thermal risk in plant communities across spatial scales. Here, we evaluate whether intraspecific variation in T crit corresponds to leaf reflectance spectra (400–2,500 nm) to identify mechanisms associated with T crit in field conditions and assess the potential of its estimation using remote sensing platforms. We measured T crit using temperature response curves of minimal fluorescence ( F o ) along with corresponding leaf reflectance spectra in two foundation tree species: Populus fremontii (US Southwest) and Metrosideros polymorpha (Hawai'i). P. fremontii was sampled under both moderate (<40°C) and extreme (>45°C) heat. Consistent spectral signatures of T crit emerged across species and sampling conditions, with the strongest signatures in P. fremontii under extreme heat. In P. fremontii, spectra captured up to roughly half of T crit variation and allowed T crit estimation ( R 2 = 0.24–0.30; RMSE < 1.0°C) and classification of high‐versus low‐T crit (71%–77% accuracy). Across both species, T crit tended to increase with spectral indices reflecting higher chlorophyll content and lower carotenoids, nonphotochemical quenching, and leaf water content. These findings suggest that variation in PSII thermal tolerance is linked to fundamental biochemical properties of leaves, which are reflected in their optical traits. As climate extremes intensify, spectral screening and scaling of T crit via remote sensing may support improved conservation, management, and risk assessment in vulnerable ecosystems.

  PublisherDOI

• Global 10-meter seagrass maps

  Zenodo (CERN European Organization for Nuclear Research) · 2026-02-14

  datasetOpen accessSenior author

  This dataset provides the first spatially consistent, global-scale seagrass extent maps at 10-meter resolution, designed to support coastal conservation planning, ecosystem monitoring, and blue carbon assessments. The maps capture global shallow-water seagrass distribution for two time periods: 2019–2020 and 2023–2024, enabling analysis of spatial patterns, persistence, and change over time. Seagrass extent is provided as GeoTIFF raster files at native 10-m spatial resolution, compatible with standard GIS and remote-sensing platforms. The dataset is optimized for integration into conservation workflows, national greenhouse gas inventories, restoration prioritization, and large-scale ecological analyses.

  PublisherDOI

• Disentangling heritability and plasticity effects on Populus fremontii leaf reflectance across a temperature gradient

  Oecologia · 2025-10-08 · 2 citations

  article
  PublisherDOI

• Duration of Super-Emitting Oil & Gas Methane Sources

  2025-05-07 · 1 citations

  preprintOpen access

  The duration of super-emitting events in oil & gas basins remains poorly understood but is key for informing reporting programs and mitigation strategies. Carbon Mapper conducted intensive aerial surveys from April 30 to May 17, 2024, over the New Mexico portion of the Permian Basin to estimate super-emitter durations directly from observations, covering 276,000 wells, 1100 compressor stations, 175 gas processing plants, and 27,000 km of pipeline. During the campaign, we detected over 500 super-emitting sources and surveyed over 300 of these sources repeatedly. Over the repeatedly surveyed region, we quantified total emissions by integrating individual events with observationally constrained event durations (5.98 -14.7 Gg CH4) and compared this estimate to the total emissions derived from basin average snapshots (12.7  0.92 Gg CH4). We show that this emissions gap can plausibly be reconciled through assumptions on missed detections, particularly given the strong relationship between characteristic event duration, detection frequency, and diurnal variability. We attribute each event to specific infrastructure types and find that emissions from compressors were detected most frequently and generally exhibit long emission durations. A small subset of sources (18 total), mostly compressors, persistently emitted throughout the entire campaign, representing a near-term opportunity for mitigation. Sustained and frequent wide-area monitoring is crucial for capturing rare, but significant super-emitter events that, together with other sources, drive basin-level variability and emission intensity.

  PublisherOA PDFDOI

• Reflections: Spectral Investigation of Black Band Disease in Hawaiian Corals

  Remote Sensing · 2025-09-19 · 1 citations

  articleOpen accessSenior author

  Coral reefs are essential to the cultural, ecological, and economic well-being of Hawai‘i’s communities, yet they face increasing threats from environmental changes and localized stressors, including coral disease. Detecting coral disease often relies on the visible appearance of lesions; however, in the case of black-band disease (BBD), this visual cue appears too late, as disease progression can cause an average rate of tissue loss of up to 5.7 cm2 per day over two months, followed by partial or full colony mortality. Reflectance spectroscopy offers a promising tool for detecting subtle spectral changes associated with coral health before visible symptoms emerge, yet few studies have applied this method to coral disease. In situ spectroscopy was used to measure the spectral reflectance of health conditions in Montiporid corals at ‘Anini Reef, Kaua‘i, USA. Discriminant analysis revealed that visually identical tissue types—live tissue on colonies with BBD (liveD) and live tissue on colonies without BBD (liveL)—were spectrally distinct. In contrast, BBD lesions (disease) and adjacent tissue that appeared healthy (transition) exhibited similar spectral signatures. Analyses identified three spectrally distinct tissue health conditions with a misclassification rate of 12.8%. These findings highlight the potential of reflectance spectroscopy for early coral disease detection, which could improve response times and support more effective coral reef conservation efforts.

  PublisherOA PDFDOI

• Persistent Geographic Patterns of Coral Recruitment in Hawaiʻi

  Oceans · 2025-12-01

  articleOpen access1st authorCorresponding

  Coral life cycle dynamics are poorly understood in most reefs, especially at the large geographic scales commensurate with ocean transport, genetic flow, and other synoptic scale processes. We present a spatially explicit, large-scale, and multi-temporal study of coral settlement along a 30 km long reef system in the Southwest portion of Hawaiʻi Island. Here, we focused on interannual variability in coral recruitment from 2021 to 2024, a period without a major marine heatwave. We used stratified random site selection to place 320 coral settlement tiles at 32 sites (10 tiles per site) at 10 ± 3 m water depth annually to monitor recruitment of the three most common coral genera found in the region (Montipora, Pocillopora, Porites). Site-level interannual variability in coral recruitment was high yet the overall geographic distribution of recruits was consistent through time. This occurred despite a decrease in benthic temperature and recruitment rates during the study period. Persistent geographic patterns in coral recruitment strengthen our understanding of mechanisms and conditions that drive reef resilience. They also strongly suggest a need to protect areas of high recruitment while studying drivers of low recruitment in contrasting habitats. This approach will further increase support of coral production in an era of climate- and coastal pollution-driven declines in coral reefs.

  PublisherOA PDFDOI

• Mapping distribution patterns of invasive alien species in the Santa Monica Mountains using airborne imaging spectroscopy and line-point transect data

  GIScience & Remote Sensing · 2025-06-10

  articleOpen access

  The Santa Monica Mountains National Recreation Area (SMMNRA) is a region of ecological importance, vulnerable to ecosystem degradation due to climate change and the spread of invasive plant species (IPS). Despite wide recognition of the presence and rapid expansion of invasive species in the SMMNRA, few studies have quantified the proportion and distribution of IPS in the region. A combination of high-resolution airborne imaging spectroscopy data and line-point transect data was used to model the distributions of five target IPS. A support vector machine model was applied to the imaging spectroscopy data and achieved an overall accuracy of 93.1%±2.2% over 10 iterations. Additionally, spatial autocorrelation was used to delineate clustering patterns of the five species in both datasets. The species distribution maps and cluster maps derived from both the transects and remote sensing data were compared and contrasted to determine the effectiveness of both approaches for identifying regions of concentrated cover and small cover fractions of the five target IPS. Both datasets revealed species from the Poaceae family were most abundantly distributed in the SMMNRA, followed by Brassicaceae and Asteraceae, though species-level abundance rankings differed. Areas of expansive IPS cover were consistently identified in both the transect and imaging spectroscopy datasets, however, results diverged in heterogeneous landscapes. Transect-based clusters indicated low IPS dominance, while imaging spectroscopy more effectively captured spatial heterogeneity. These results emphasize the value of fine-spatial and spectral resolution data for detecting IPS patterns in complex environments and demonstrate how combining airborne imaging spectroscopy with field-based methods can inform IPS management.

  PublisherDOI

Recent grants

• Doctoral Dissertation Research: Predicting the spread of Rapid Ohia Death and detecting resistant varieties of Metrosideros polymorpha

  NSF · $31k · 2022–2025

• Collaborative Research: Developing integrated trait-based scaling theory to predict community change and forest function in light of global change

  NSF · $215k · 2015–2019

• Collaborative Research: Disturbance, Succession, and Nutrient Availability: Patterns, Mechanisms, Interactions

  NSF · $299k · 2007–2012

• Collaborative Research: Developing integrated trait-based scaling theory to predict community change and forest function in light of global change

  NSF · $44k · 2019–2020

• Amazon forest response to droughts, fire, and land use: a multi-scale approach to forest dieback

  NSF · $1.0M · 2013–2017

Frequent coauthors

• Roberta E. Martin

  Arizona State University

  219 shared

• David Knapp

  Applied Materials (United States)

  203 shared

• Nicholas R. Vaughn

  Arizona State University

  96 shared

• Michael Keller

  International Institute of Tropical Forestry

  81 shared

• Jiwei Li

  Arizona State University

  79 shared

• Stuart Phinn

  70 shared

• Nicholas Murray

  James Cook University

  69 shared

• Chris Roelfsema

  University of Queensland

  69 shared

Education

• Ph.D., Ecology

  University of California, Berkeley

  1995

• M.S., Ecology

  University of California, Berkeley

  1991

• B.S., Ecology

  University of California, Santa Barbara

  1988

Awards & honors

• multiple scientific and sustainability awards
• elected member of the U.S. National Academy of Sciences