Peter Schlosser

• PhD
• Vice President and Vice Provost at Arizona State University

The years 2023 and 2024 were characterized by unprecedented warming across the globe, underscoring the urgency of climate action. Robust science advice for decision makers on subjects as complex as climate change requires deep cross- and interdisciplinary understanding. However, navigating the ever-expanding and diverse peer-reviewed literature on...

The physical and biogeochemical properties of the western Arctic Ocean are rapidly changing, resulting in cascading shifts to the local ecosystems. The nutrient‐rich Pacific water inflow to the Arctic through the Bering Strait is modified on the Chukchi and East Siberian shelves by brine rejection during sea ice formation, resulting in a strong hal...

Plain Language Summary In this study, we analyze tritium and helium‐3 (³He) data from 21 oceanographic expeditions conducted over 27 years to track the movement and speed of the Atlantic Layer—waters originating from the North Atlantic, found in the Arctic Ocean. The combined measurement of tritium and ³He acts as a “natural clock,” allowing us to...

Plain Language Summary The Indonesian seas, at the center of the Indo‐Pacific Intersection, are recognized as a global hotspot of marine biodiversity. However, nutrient (e.g., nitrate) cycling in the Indonesian seas is poorly understood, such that nutrient sources and fluxes sustaining biological production remain unknown. The Indonesian seas lie o...

Climate change research is broad, diverse and constantly growing. Cross- and interdisciplinary understanding is essential for generating robust science advice for policy. However, it is challenging to prioritise and navigate the ever-expanding peer-reviewed literature. To address this, we gathered input from experts across various research fields t...

Climate change research is broad, diverse and constantly growing. Cross- and interdisciplinary understanding is essential for generating robust science advice for policy. However, it is challenging to prioritise and navigate the ever-expanding peer-reviewed literature. To address this, we gathered input from experts across various research fields t...

Non-technical summary We identify a set of essential recent advances in climate change research with high policy relevance, across natural and social sciences: (1) looming inevitability and implications of overshooting the 1.5°C warming limit, (2) urgent need for a rapid and managed fossil fuel phase-out, (3) challenges for scaling carbon dioxide r...

Non-technical summary There is increasing evidence of extreme events and irreversible damage occurring faster than expected. Despite inescapable evidence of intersecting crises facing the Earth system and numerous efforts and agreements, global society is not on track to achieve its sustainability objectives. The 10 ‘Must Haves’ initiative aims to...

There is a growing recognition that responding to climate change necessitates urban adaptation. We sketch a transdisciplinary research effort, arguing that actionable research on urban adaptation needs to recognize the nature of cities as social networks embedded in physical space. Given the pace, scale and socioeconomic outcomes of urbanization in...

Groundwater supports agriculture and provides domestic water for over 250 million people in the Bengal Basin. Here we investigate the source of groundwater recharge using over 2500 stable water isotope measurements from the region. We employ a Monte Carlo statistical analysis to find distributions of possible components of recharge by accounting fo...

Non-technical summary We summarize what we assess as the past year's most important findings within climate change research: limits to adaptation, vulnerability hotspots, new threats coming from the climate–health nexus, climate (im)mobility and security, sustainable practices for land use and finance, losses and damages, inclusive societal climate...

Dr. rer.nat. Clemens Schlosser, a physicist by training, well known to the German and international scientific community for his contributions to the monitoring of environmental radioactivity and especially the radionuclide component of the International Monitoring System, passed away on August 2, 2021 after a long and brave battle with ALS. Even d...

In this perspective on the future of the Arctic, we explore actions taken to mitigate warming and adapt to change since the Paris agreement on the temperature threshold that should not be exceeded in order to avoid dangerous interference with the climate system. Although 5 years may seem too short a time for implementation of major interventions, i...

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 about the remaining options to achieve the Paris Agreement goals, through overcoming political barriers to carbon pricing, taking into account non-CO 2 factors, a well-designed implem...

We present tritium (³H) and helium isotope (δ³He) data from the South China Sea (SCS), to estimate apparent oxygen utilization rates (AOURs). The observed δ³He values are close to the theoretical solubility equilibrium value of ∼ -1.7% in the upper mixed layer, followed by an increase with depth down to ∼1500 m. Below 1500 m depth, δ³He is homogeno...

COVID-19 has revealed that science needs to learn how to better deal with the irreducible uncertainty that comes with global systemic risks as well as with the social responsibility of science towards the public good. Further developing the epistemological principles of new theories and experimental practices, alternative investigative pathways and...

Climate science provides strong evidence of the necessity of limiting global warming to 1.5°C, in line with the Paris Climate Agreement. The IPCC 1.5°C special report (SR1.5) presents 414 emissions scenarios modelled for the report, of which around 50 are classified as '1.5°C scenarios', with no or low temperature overshoot. These emission scenario...

Groundwater supports agriculture and provides domestic water for over 250 million people in the Bengal Basin. Our analysis of stable water isotope ratios in rain, surface, and groundwater shows that the proportion of groundwater recharge originating from stagnant surface water bodies has increased by about 50% over the last seventy years while the...

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 weakeni...

COVID-19 has been a stress test for our globalized society. The results, thus far, have not been encouraging. While responses and outcomes have varied across regions and countries, the pandemic has also revealed severe weaknesses in coordination at all scales, from local and regional to national and global. There are many reasons for this lack of c...

Across South Asia, millions of villagers have reduced their exposure to high‐arsenic (As) groundwater by switching to low‐As wells. Isotopic tracers and flow modeling are used in this study to understand the groundwater flow system of a semi‐confined aquifer of Pleistocene (>10 kyr) age in Bangladesh that is generally low in As but has been perturb...

Confining clay layers typically protect groundwater aquifers against downward intrusion of contaminants. In the context of groundwater arsenic in Bangladesh, we challenge this notion here by showing that organic carbon drawn from a clay layer into a low-arsenic pre-Holocene (>12 kyr-old) aquifer promotes the reductive dissolution of iron oxides and...

A major surface circulation feature of the Arctic Ocean is the Transpolar Drift (TPD), a current that transports river‐influenced shelf water from the Laptev and East Siberian Seas toward the center of the basin and Fram Strait. In 2015, the international GEOTRACES program included a high‐resolution pan‐Arctic survey of carbon, nutrients, and a sui...

Elevated arsenic in Bengal Basin aquifers threatens human health. Most deep (>150 m) groundwater in Pleistocene aquifers is low in arsenic; however higher concentrations have been reported in the southwest border region. Here, we establish that this extensive arsenic contamination at depth is not associated with well failure. A combination of geoch...

Sea ice is an important control on gas exchange and primary production in polar regions. We measured net oxygen production (NOP) and gross oxygen production (GOP) using near-continuous measurements of the O2/Ar gas ratio and discrete measurements of the triple isotopic composition of O2, during the transition from ice-covered to ice-free conditions...

Changing the scientific approach to fast transitions to a sustainable world. Improving knowledge production for sustainable policy and practice

Plain Language Summary The water transfer between the Pacific and Indian Oceans, commonly referred to as the Indonesian Throughflow (ITF), is the only tropical interbasin oceanic pathway, which plays a critical role in the redistribution of heat and mass, affecting both the regional and global climate systems. Due to the strong variability at both...

Tritium and helium isotope data provide key information on ocean circulation, ventilation, and mixing, as well as the rates of biogeochemical processes and deep-ocean hydrothermal processes. We present here global oceanic datasets of tritium and helium isotope measurements made by numerous researchers and laboratories over a period exceeding 60 yea...

Tritium and helium isotope data provide key information on ocean circulation, ventilation, and mixing, as well as the rates of biogeochemical processes, and deep-ocean hydrothermal processes. We present here global oceanic datasets of tritium and helium isotope measurements made by numerous researchers and laboratories over a period exceeding 60 ye...

Coral reefs are found predominately in tropical and subtropical areas and are sites of active carbon cycling. Knowledge of gas transfer velocities is necessary for carbon cycle studies in coral reef environments, and past studies in these environments have used wind speed/gas exchange parameterizations intended for the open ocean. In order to deter...

Tectonic landforms reveal that the West Antarctic Ice Sheet (WAIS) lies atop a major volcanic rift system. However, identifying subglacial volcanism is challenging. Here we show geochemical evidence of a volcanic heat source upstream of the fast-melting Pine Island Ice Shelf, documented by seawater helium isotope ratios at the front of the Ice Shel...

Sea ice is an important control on gas exchange and primary production in polar regions. We measured net oxygen production and gross oxygen production using near-continuous measurements of the O2 / Ar gas ratio and discrete measurements of the triple isotopic composition of O2 in the Bras d'Or Lake, an estuary in Nova Scotia, Canada, as the bay tra...

Dual-domain transport is an alternative conceptual and mathematical paradigm to advection-dispersion for describing the movement of dissolved constituents in groundwater. Here we test the use of a dual-domain algorithm combined with advective pathline tracking to help reconcile environmental tracer concentrations measured in springs within the Shen...

The presence of sea ice acts as a physical barrier for air-sea exchange. On the other hand it creates additional turbulence due to current shear and convection during ice formation. We present results from a laboratory study that demonstrate how shear and convection in the ice-ocean boundary layer can lead to significant gas exchange. In the absenc...

Hydrothermal vents along the ocean's tectonic ridge systems inject superheated water and large amounts of dissolved metals that impact the deep ocean circulation and the oceanic cycling of trace metals. The hydrothermal fluid contains dissolved mantle helium that is enriched in ³He relative to the atmosphere, providing an isotopic tracer of the oce...

The scale of the decarbonisation challenge to meet the Paris Agreement is underplayed in the public arena. It will require precipitous emissions reductions within 40 years and a new carbon sink on the scale of the ocean sink. Even then, the world is extremely likely to overshoot. A catastrophic failure of policy, for example, waiting another decade...

The Columbia Climate Center, in partnership with World Wildlife Fund, Woods Hole Research Center, and Arctic 21, held a workshop titled A 5 C Arctic in a 2 C World on July 20 and 21, 2016. The workshop was co-sponsored by the International Arctic Research Center (University of Alaska Fairbanks), the Arctic Institute of North America (Canada), the M...

The scale of the decarbonisation challenge to meet the Paris Agreement is underplayed in the public arena. It will require precipitous emission reductions and a new carbon sink on the scale of the ocean sink within 40 years. Even then, the world is extremely likely to overshoot. A catastrophic failure of policy, for example waiting another decade f...

Recent trends and climate models suggest that the Arctic summer sea ice cover is likely to be lost before climate interventions can stabilize it. There are environmental, socioeconomic and sociocultural arguments for, but also against restoring and sustaining current conditions. Even if global warming can be reversed, some people will experience ic...

More than 100,000 community wells have been installed in the 150-300 m depth range throughout Bangladesh over the past decade to provide low-arsenic drinking water (<10 μg/L As), but little is known about how aquifers tapped by these wells are recharged. Within a 25 km2 area of Bangladesh east of Dhaka, groundwater from 65 low-As wells in the 35-24...

Knowledge of air-water gas transfer velocities and water residence times are necessary to study the fate of mangrove derived carbon exported into surrounding estuaries, and ultimately to determine carbon balances in mangrove ecosystems. For the first time, the 3He/SF6 dual tracer technique, which has been proven to be a powerful tool to determine g...

The spatial heterogeneity of dissolved arsenic (As) concentrations in shallow groundwater of the Bengal Basin has been attributed to transport of As (and reactive carbon) from external sources or to the release of As from within grey sand formations. We explore the latter scenario in this detailed hydrological and geochemical study along a 300 m tr...

Laser-based spectroscopic techniques, such as cavity ring-down spectroscopy (CRDS), provide a new, cost effective and more widely available approach to measure the oxygen isotope ratio in water molecules, 18O/ 16O (δ18O), and are used increasingly to measure δ18O in the world's oceans. Here, we present results from an interlaboratory comparison des...

Sea ice is a defining feature of the polar marine environment. It is a critical domain for marine biota and it regulates ocean-atmosphere exchange, including the exchange of greenhouse gases such as CO2 and CH4. In this study, we determined the rates and pathways that govern gas transport through a mixed sea ice cover. N2O, SF6, 3He, 4He, and Ne we...

The development of human civilisations has occurred at a time of stable climate. This climate stability is now threatened by human activity. The rising global climate risk occurs at a decisive moment for world development. World nations are currently discussing a global development agenda consequent to the Millennium Development Goals (MDGs), which...

The Eocene deposits of Kazan Basin in Turkey contain a rare trona mineral which is planned to be extracted by solution mining. The complex flow dynamics and mixing mechanisms as noted from previous hydraulic and hydrochemical data need to be augmented with environmental tracer and noble gas data to develop a conceptual model of the system for the a...

The aim of this study is to characterize the hydrogeological framework above the trona reserve in Kazan Basin by using the environmental isotopes of oxygen, hydrogen and carbon, chlorofluorocarbons and noble gases. There are four basic rock sequences exposed in the study area which are, from bottom to top, Paleozoic Metamorphics, Eocene sequences (...

Carbon budgets for the polar oceans require better constraint on air–sea gas exchange in the sea ice zone (SIZ). Here, we utilize advances in the theory of turbulence, mixing and air–sea flux in the ice–ocean boundary layer (IOBL) to formulate a simple model for gas exchange when the surface ocean is partially covered by sea ice. The gas transfer v...

Hydrographic data from the Arctic Ocean show that freshwater content in the Lincoln Sea, north of Greenland, increased significantly from 2007 to 2010, slightly lagging changes in the eastern and central Arctic. The anomaly was primarily caused by a decrease in the upper ocean salinity. In 2011 upper ocean salinities in the Lincoln Sea returned to...

For the first time in serveral years, the El Nino-Southern Oscillation did not dominate regional climate conditions around the globe. A weak La Ni a dissipated to ENSOneutral conditions by spring, and while El Nino appeared to be emerging during summer, this phase never fully developed as sea surface temperatures in the eastern conditions. Neverthe...

Carbon budgets for the polar oceans require better constraint on air-sea gas exchange in the sea ice zone (SIZ). Here, we utilize recent advances in the theory of turbulence, mixing and air-sea flux in the ice-ocean boundary layer (IOBL) to formulate a simple model for gas exchange when the surface ocean is partially covered by sea ice. The gas tra...

Measured concentrations of environmental tracers in spring discharge from a karst aquifer in the Shenandoah Valley, USA, were used to refine a numerical groundwater flow model. The karst aquifer is folded and faulted carbonate bedrock dominated by diffuse flow along fractures. The numerical model represented bedrock structure and discrete features...

Measurements of low-level concentrations of halogenated volatile organic compounds (VOCs) and estimates of groundwater age interpreted from 3H/3He and SF6 data have led to an improved understanding of groundwater flow, water sources, and transit times in a karstic, fractured, carbonate-rock aquifer at the Leetown Science Center (LSC), West Virginia...

We present measurements of oxygen isotope ratios and nutrient concentrations along the 2005 Arctic Ocean Section aboard the icebreaker Oden. The data are used to estimate freshwater contributions from meteoric water (mainly river runoff), sea-ice meltwater, and Chukchi Sea shelf water, itself a combination of Pacific and indigenous Arctic water typ...

Environmental isotopes and noble gases in groundwater samples from the Kazan Trona Ore Field are studied to establish the temperature change between the Holocene and the late Pleistocene. Noble gas temperatures (NGTs) presented in this study add an important facet to the global paleotemperature map in the region between Europe and North Africa. The...

International Workshop on Tracer Applications of Noble Gas Radionuclides; Argonne, Illinois, 21-22 June 2012 The noble gas radionuclides krypton-81 (81Kr; 229,000-year half-life), krypton-85 (85Kr; 10.8-year half-life), and argon-39 (39Ar; 269-year half-life) have ideal properties for tracing fluid transport in Earth systems. Their principal applic...

Human activities increasingly lead to climate change, overuse of water, hazards and the destruction of biodiversity — to name just a few. Earth scientists need to take on the challenge of serving society on these issues, in close collaboration with engineering, social sciences and the humanities.

Elevated mixing ratios of chlorofluorocarbons (CFC-11 and CFC-12), and sulfur hexafluoride (SF6) have been observed at Lamont-Doherty Earth Observatory (LDEO), located approximately 25 km north of New York City (NYC). Emissions and transport of these gases are of interest because of their global warming potential, the role of CFCs in depletion of s...

A gas tight, small diameter, lightweight rosette, supporting equipment and an effective operational protocol has been developed for aircraft supported sampling of sea water across the Lincoln Sea. The system incorporates a commercial off the shelf CTD electronics (SBE19+ sensor package and SBE33 deck unit) to provide real-time measurement data at t...

Responding to climate change challenges in the near and far future, will require a wide range of knowledge, skills and a sense of the complexities involved. Since 1995, Columbia University and Barnard College have offered an undergraduate class that strives to provide students with some of these skills. The 'Climate System' course is a component of...

While many institutions now have courses that teach climate from an earth or biological systems perspective, it is more challenging to address how to respond to climate change. Implementing adaptation and mitigation measures requires an interdisciplinary approach of involving stakeholders, identifying needs, resolving conflicts and taking action at...

1] The advance and retreat of sea ice produces seasonal convection and stratification, dampens surface waves and creates a separation between the ocean and atmosphere. These are all phenomena that can affect the air‐sea gas transfer velocity (k 660), and therefore it is not straightforward to determine how sea ice cover modulates air‐sea flux. In t...

Air–water gas exchange is an important process in aquatic systems, including tidal rivers and estuaries. While there are now reliable and routine methods for determining gas exchange over a range of temporal and spatial scales in the ocean and these measurements have resulted in widely used wind speed parameterizations to calculate air–sea gas exch...

During the 2007 UK SOLAS Deep Ocean Gas Exchange Experiment in the northeast Atlantic Ocean, we conducted the first ever study of the effect of a deliberately released surfactant (oleyl alcohol) on gas transfer velocities (kw) in the open ocean. Exchange rates were estimated with the 3He/SF6 dual tracer technique and from measured sea‐to‐air DMS fl...

Drinking shallow groundwater with naturally elevated concentrations of arsenic is causing widespread disease in many parts of South and Southeast Asia. In the Bengal Basin, growing reliance on deep (>150 m) groundwater has lowered exposure. In the most affected districts of Bangladesh, shallow groundwater concentrations average 100 to 370 μg L(-1),...

The Arctic Ocean is changing rapidly as Earth's climate warms. To document and understand these changing ocean conditions, we developed a rosette that collects high-quality oceanographic data and is deployed from an aircraft through a 30.5 cm diameter hole drilled in the ice (Figure 1). The rosette is modular, with the modules attached vertically o...

Two 3He/SF6 dual-gas tracer injections were conducted during the Southern Ocean Gas Exchange Experiment (SO GasEx) to determine gas transfer velocities. During the experiment, wind speeds of up to 16.4 m s -1 were encountered. A total of 360 3He and 598 SF 6 samples were collected at 40 conductivity-temperature-depth (CTD) rosette casts and two pum...

A dual tracer experiment was carried out during the SAGE experiment using the inert tracers SF6 and 3He, in order to determine the gas transfer velocity, k, at high wind speeds in the Southern Ocean. Wind speed/gas exchange parameterization is characterised by significant variability and we examine the major measurement uncertainties that contribut...

Gas diffusion through the porous microstructure of sea ice represents a pathway for ocean–atmosphere exchange and for transport of biogenic gases produced within sea ice. We report on the experimental determination of the bulk gas diffusion coefficients, D, for oxygen (O2) and sulphur hexafluoride (SF6) through columnar sea ice under constant ice t...

The significant increase in the extent of ice-free water during summer in the Arctic Ocean is expected to increase surface biological productivity. The magnitude and pattern of the response is difficult to predict however, given the sparse sampling of nutrient levels in this region, and the likelihood that nutrient availability may constrain the pr...

Arctic change is an important indicator of changes in global climate, as the poles of the earth are affected earlier and more strongly by changing climate. One of the key components of Arctic change with implications for global ocean circulation is the Arctic freshwater budget. Studying freshwater variability in the Arctic can give a clearer pictur...