Engineering topics

Thomson, Allison M

Publications and source records attributed to Thomson, Allison M.

5 records

DOE OSTI2013

Implications of simultaneously mitigating and adapting to climate change: Initial experiments using GCAM

Historically climate impacts research and climate mitigation research have been two separate and independent domains of inquiry. Climate mitigation research has investigated greenhouse gas emissions assuming that climate is unchanging. At the same time climate mitigation research has investigated the implications of climate change on the assumption that climate mitigation will proceed without affecting the degree of climate impacts or the ability of human and natural systems to adapt. The Global Change Assessment Model (GCAM) has largely been employed to study climate mitigation. Here we explore the development of capabilities to assess climate change impacts and adaptation within the GCAM model. These capabilities are being developed so as to be able to simultaneously reconcile the joint implications of climate change mitigation, impacts and adaptive potential. This is an important step forward in that it enables direct comparison between climate mitigation activities and climate impacts and the opportunity to understand interactions between the two.

Calvin, Katherine V↗

DOE OSTI2012

Multi-Year Lags between Forest Browning and Soil Respiration at High Northern Latitudes

High-latitude northern ecosystems are experiencing rapid climate changes, and represent a large potential climate feedback because of their high soil carbon densities and shifting disturbance regimes. A significant carbon flow from these ecosystems is soil respiration (RS, the flow of carbon dioxide, generated by plant roots and soil fauna, from the soil surface to atmosphere), and any change in the high-latitude carbon cycle might thus be reflected in RS observed in the field. This study used two variants of a machine-learning algorithm and least squares regression to examine how remotely-sensed canopy greenness (NDVI), climate, and other variables are coupled to annual RS based on 105 observations from 64 circumpolar sites in a global database. The addition of NDVI roughly doubled model performance, with the best-performing models explaining ~62% of observed RS variability

carbon cycling↗

DOE OSTI2012

A proposal for a new scenario framework to support research and assessment in different climate research communities

In this paper, we propose a scenario framework that could provide a scenario thread through the different climate research communities (climate change vulnerability, impact, and adaptation (VIA) and mitigation) in order to provide assessment of mitigation and adaptation strategies and other VIA challenges. The scenario framework is defined across two main axes. One is defined by the radiative forcing levels (climate signal) of the Representative Concentration Pathways (RCPs). The second axis is defined by socio-economic development and comprises elements that affect the capacity for adaptation and mitigation but also exposure to climate impacts. The proposed set of scenarios derived from this framework are limited in number, allow for comparison across various mitigation and adaptation levels, address a range of vulnerability characteristics, provide information across climate forcing and vulnerability states and spans a full century time scale. Scenario assessment based on the proposed framework would strengthen cooperation between integrated-assessment modelers, climate modelers and the VIA research community, and most importantly, facilitate the development of more consistent and comparable research within and across communities.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2011

Harmonization of Land-Use Scenarios for the Period 1500-2100: 600 Years of Global Gridded Annual Land-Use Transitions, Wood Harvest, and Resulting Secondary Lands

In preparation for the fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), the international community is developing new advanced Earth System Models (ESM) to assess the combined effects of human activities (e.g. land use and fossil fuel emissions) on the carbon-climate system. In addition, four Representative Concentration Pathway (RCP) scenarios of the future (2005-2100) are being provided by four Integrated Assessment Model (IAM) teams to be used as input to the ESMs for future carbon-climate projections (Moss et al., 2010). The diversity of approaches and requirements among IAMs and ESMs for tracking land-use change, along with the dependence of model projections on land-use history, presents a challenge for effectively passing data between these communities and for smoothly transitioning from the historical estimates to future projections. Here, a harmonized set of land-use scenarios are presented that smoothly connects historical reconstructions of land use with future projections, in the format required by ESMs.

09 BIOMASS FUELS↗

DOE OSTI2011

The Representative Concentration Pathways: An Overview

This paper summarizes the development process and main characteristics of the Representative Concentration Pathways (RCPs), a set of four new scenarios developed for the climate modeling community as a basis for long-term and near-term modeling experiments. The four RCPs together span the range of year 2100 radiative forcing values found in the open literature, i.e. from 2.6 to 8.5 W/m2. The RCPs are the product of an innovative collaboration between integrated assessment modelers, climate modelers, terrestrial ecosystem modelers and emission inventory experts. The resulting product forms a comprehensive data set with high spatial and sectoral resolutions for the period extending to 2100. Land use and emissions of air pollutants and greenhouse gases are reported mostly at a 0.5 x 0.5 degree spatial resolution, with air pollutants also provided per sector (for well-mixed gases, a coarser resolution is used). The underlying integrated assessment model outputs for land use, atmospheric emissions and concentration data were harmonized across models and scenarios to ensure consistency with historical observations while preserving individual scenario trends. For most variables, the RCPs cover a wide range of the existing literature. The RCPs are supplemented with extensions (Extended Concentration Pathways, ECPs), which allow climate modeling experiments through the year 2300. The RCPs are an important development in climate research and provide a potential foundation for further research and assessment, including emissions mitigation and impact analysis.

54 ENVIRONMENTAL SCIENCES↗