Earth Systems

To avert the worst impacts of climate change, from extreme flooding to devastating droughts, the world will need to cap global warming at 1.5 degrees Celsius, according to the latest United Nations IPCC Report on the Earth’s climate system. Achieving that goal means that by around 2050, the planet’s total greenhouse gas emissions will need to decline to net-zero. To that end, more and more governments and businesses are setting net-zero emissions targets.

Global net-zero emissions goals: Challenges and opportunities
Assessing the Changing Risk of Flood-producing Events in Cambridge

Abstract: In this study, we assess the potential for future changes in the frequency of summertime heavy-to-extreme precipitation events – defined as  2” of rainfall in 3 hours – across the greater Cambridge area as a result of anthropogenic global warming. The study relies upon an “analogue method” that identifies well-resolved large scale, daily-averaged atmospheric patterns associated with the occurrence of local extreme events, and thus enables evaluating the ability of climate models to simulate conditions conducive to such extremes that occur at unresolvable spatial scales. We find that climate models from the Phase 5 of the Coupled Model Intercomparison Project (CMIP5) consistently reproduce the historical occurrence of these synoptic-scale patterns associated with the occurrence of the heavy-to-extreme precipitation events observed across the greater Cambridge area. Applying these analogues into the future across all the CMIP5 model projections, there is weak evidence of any considerable trend in the frequency of these heavy-to-extreme events out to the end of the 21st century. Furthermore, analyses that consider a strong climate-change mitigation scenario show no salient effect on the ensemble-median change as well as the interquartile and minimum-maximum ranges. Further work is warranted that considers: a more robust sampling of associated spatial patterns, rather than a pooled or average spatial pattern, to the local extreme; a more explicit treatment of the sub-daily atmospheric patterns that coincide with the local, sub-daily (i.e., 3-hour) event.

Impacts of a near-future supersonic aircraft fleet on atmospheric composition and climate

Abstract: Supersonic aircraft will have environmental impacts distinct from those of subsonic aviation, and are once again being developed and bought. Assessments of supersonic aircraft emissions impacts over the last decade have focused on the ozone and climate impacts of nitrogen oxides and water vapor, but assumed zero-sulfur fuel, zero black carbon emissions, and neglect likely design constraints on near-future engine technology. We assess the impacts on atmospheric composition and non-CO2 climate forcing of a near-future supersonic aircraft fleet with current-generation engine technology burning fossil-based kerosene fuel with current-day sulfur content.

Using vehicle performance modeling, market demand projection and global atmospheric chemistry-transport modeling, we find that a supersonic fleet flying at Mach 1.6 and 15–17 km altitude, burning 19 Tg of fuel each year and emitting 170 Gg of NOx would cause a 0.046% reduction in global column ozone. We estimate the radiative forcing (climate impact) from changes in atmospheric concentrations of ozone (2.9 mW m−2), water vapor (1.3 mW m−2), carbonaceous and inorganic aerosols (−6.6 mW m−2), and methane (−0.65 mW m−2), resulting in a net non-CO2, non-contrail forcing of −3.5 mW m−2 and varying from −3.0 to −3.9 mW per m2 per year to year. We also show that the use of zero-sulfur fuel would halve net ozone depletion but increases the net non-CO2 non-contrail forcing to +2.8 mW m−2 due to the loss of a cooling effect from sulfate aerosols. A smaller fleet of Mach 2.2 aircraft flying at 18–20 km and burning 14 Tg of fuel but emitting twice as much NOx per unit of fuel results in 17 times as much net ozone depletion. The net radiative forcing for this fleet is of uncertain sign, averaging −0.15 mW m−2 but varying between −3.2 and +2.0 mW per m2 per year to year.

Our results show that assessments of near-future supersonic aviation must consider the effects of fuel sulfur and black carbon alongside emissions of water vapor, NOx, and CO2, and that the net environmental impacts will be a trade-off between competing environmental concerns.

MultiSector Dynamics: Scientific Challenges and a Research Vision for 2030, A Community of Practice Supported by the United States Department of Energy's Office of Science

Executive Summary: 

This report outlines a vision for MultiSector Dynamics (MSD) as an emerging transdisciplinary field that seeks to advance our understanding of how human-Earth systems interactions shape the resources, goods, and services on which society depends. The core objective of this MSD Vision Report is to clarify core definitions, share research questions, highlight scientific opportunities, and provide steps for improving the MSD community’s capacity to support needed scientific progress.

The report has several technical audiences in mind. These include current MSD researchers, scientists working in complementary fields who wish to learn more about opportunities for engagement, and research program managers at the US Department of Energy (DOE). Additionally, the research-to-operations (R2O2R) and community building elements of the report hold value for a broad array of US federal agencies as well as other governments and international organizations. As a transdisciplinary endeavor, the vision presented here should have elements that directly interest sectoral analysts engaged in energy, water, agriculture, transportation, health, etc. We hope these audiences will find the report a helpful reference and a source of opportunities for shaping the future of MSD science. 

The report incorporates ideas and insights from the members of the recently established MSD Community of Practice (CoP). MSD finds its roots in a number of research fields and communities, including integrated assessment; impacts, adaptation, and vulnerability; Earth system science; and complex adaptive systems. However, the MSD CoP draws its conceptual basis from a 2016 workshop sponsored and led by the DOE, "Understanding Dynamics and Resilience in Complex Interdependent Systems: Prospects for a Multi-Model Framework and Community of Practice," organized with other federal agencies and hosted by the US Global Change Research Program. The rationale for the CoP is that research on understanding risks and opportunities arising from tightly connected human and natural systems is fragmented across several fields, requiring improved collaboration and synthesis to accelerate needed scientific advances. A CoP Facilitation Team and a Scientific Steering Group (SSG) were launched in 2019 to advance the needed collaborations and scientific synthesis. Since that time, an initial core group of projects supported by DOE’s MSD research program has provided input to the development of the CoP through activities including a community questionnaire to identify current tools and research interests, regular meetings of technical working groups (WGs), MSD community briefings, research workshops, and the MSD CoP website.

The members of the MSD SSG and Facilitation Team are responsible for drafting this report, based on the above community inputs as well as a formal review of recent research within related fields such as Earth system science, integrated assessment modeling, economics, decision science, socio-ecological systems, socio-environmental systems, complexity science, systems engineering, energy transitions, urban systems, and coastal dynamics. Members of the major projects in the DOE MSD research program provided extensive comments on a first draft of the report (see Chapter 2.2 for descriptions and links to projects' websites for additional information). Robert Vallario, program manager for the DOE Earth and Environmental Systems Modeling MSD research program area, has provided insights, perspectives, and comments that have been critically important throughout the process. The SSG and the Facilitation Team thank these individuals for their many contributions and ongoing support. In addition, the Facilitation Team thanks the DOE Office of Science, Earth and Environmental System Modeling program for financial support of its activities through the Integrated Multisector Multiscale Modeling (IM3) project.

MultiSector Dynamics: Advancing the science of complex adaptive human-Earth systems

Abstract: The field of MultiSector Dynamics (MSD) explores the dynamics and co-evolutionary pathways of human and Earth systems with a focus on critical goods, services, and amenities delivered to people through interdependent sectors. This commentary lays out core definitions and concepts, identifies MSD science questions in the context of the current state of knowledge, and describes ongoing activities to expand capacities for open science, leverage revolutions in data and computing, and grow and diversify the MSD workforce.

Central to our vision is the ambition of advancing the next generation of complex adaptive human-Earth systems science to better address interconnected risks, increase resilience, and improve sustainability. This will require convergent research and the integration of ideas and methods from multiple disciplines. Understanding the tradeoffs, synergies, and complexities that exist in coupled human-Earth systems is particularly important in the context of energy transitions and increased future shocks.

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