Abstract
The human and Earth systems are intricately linked: Climate influences agricultural production, renewable energy potential, and water availability, for example, while anthropogenic emissions from industry and land use change alter temperature and precipitation. Such feedbacks have the potential to significantly alter future climate change. These feedbacks may also exert significant changes on 21st-century energy, agriculture, land use and carbon cycle projections, but little is known about their possible magnitudes, or about regional and sector dynamics under different forcing scenarios. Here we use an integrated Earth System Model (ESM) featuring bidirectional information exchange between an economically-oriented integrated assessment model and the ESM to examine how human-natural feedbacks operate under high and medium radiative forcing (RF) scenarios. Specifically, we examine the effect of changing land productivity on human systems, and the effect of changing land use/land cover and CO2 emissions on the Earth system. We find that the effect of coupling differs across radiative forcing levels and across regions, due to differences in the climate signal, human responses to those signals, and regional characteristics. In particular, we find reductions in cropland area due to feedbacks in both the medium and high RF scenarios. In the medium RF scenario, these reductions result in increased area for bioenergy and afforestation and reduced energy system CO2 emissions, as the carbon price in this scenario incentivizes low carbon energy sources and terrestrial carbon storage; these incentives are absent in the high RF scenario. These differences are key to understanding the possible future evolution pathways of the integrated Earth system in response to 21st century climate change. Additional models and hypothesis testing are needed to determine exactly when and how bidirectional feedbacks between human and Earth systems should be considered in future assessments.
| Original language | English |
|---|---|
| Pages (from-to) | 126-135 |
| Number of pages | 10 |
| Journal | Global and Planetary Change |
| Volume | 180 |
| DOIs | |
| State | Published - Sep 2019 |
Funding
This research was supported as part of the Energy Exascale Earth System Model (E3SM) project, funded by the U.S. Department of Energy , Office of Science , Office of Biological and Environmental Research . This research used resources of the Oak Ridge Leadership Computing Facility, which is a U.S. Department of Energy Office of Science User Facility supported under Contract DE-AC05-00OR22725 . This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 . This research also used PNNL Institutional Computing at Pacific Northwest National Laboratory. This work used the Community Earth System Model, CESM and the Global Change Assessment Model, GCAM. The National Science Foundation and the Office of Science of the U.S. Department of Energy support the CESM project. The opinions expressed in this paper are the authors alone.