Carol C. Barford

Trading carbon for food: Global comparison of carbon stocks vs. crop yields on agricultural land

Expanding croplands to meet the needs of a growing population, changing diets, and biofuel production comes at the cost of reduced carbon stocks in natural vegetation and soils. Here, we present a spatially explicit global analysis of tradeoffs between carbon stocks and current crop yields. The difference among regions is striking. For example, for each unit of land cleared, the tropics lose nearly two times as much carbon (∼120 tons·ha−1 vs. ∼63 tons·ha−1) and produce less than one-half the annual crop yield compared with temperate regions (1.71 tons·ha−1·y−1 vs. 3.84 tons·ha−1·y−1). Therefore, newly cleared land in the tropics releases nearly 3 tons of carbon for every 1 ton of annual crop yield compared with a similar area cleared in the temperate zone. By factoring crop yield into the analysis, we specify the tradeoff between carbon stocks and crops for all areas where crops are currently grown and thereby, substantially enhance the spatial resolution relative to previous regional estimates. Particularly in the tropics, emphasis should be placed on increasing yields on existing croplands rather than clearing new lands. Our high-resolution approach can be used to determine the net effect of local land use decisions.

An alternative approach for quantifying climate regulation by ecosystems

Ecosystems provide multiple benefits to people, including climate regulation. Previous efforts to quantify this ecosystem service have been either largely conceptual or based on complex atmospheric models. Here, we review previous research on this topic and propose a new and simple analytical approach for estimating the physical regulation of climate by ecosystems. The proposed metric estimates how land-cover change affects the loading of heat and moisture into the atmosphere, while also accounting for the relative contribution of wind-transported heat and moisture. Although feedback dynamics between land, atmosphere, and oceans are not modeled, the metric compares well with previous studies for several regions. We find that ecosystems have the strongest influence on surface climatic conditions in the boreal and tropical regions, where temperature and moisture changes could substantially offset or magnify greenhouse-forced changes. This approach can be extended to estimate the effects of changing land cover on local, physical climate processes that are relevant to society.

Producer and consumer responsibility for greenhouse gas emissions from agricultural production—a perspective from the Brazilian Amazon

Greenhouse gases from the combination of land use change and agriculture are responsible for the largest share of global emissions, but are inadequately considered in the current set of international climate policies. Under the Kyoto protocol, emissions generated in the production of agricultural commodities are the responsibility of the producing country, introducing potential inequities if agricultural products are exported. This study quantifies the greenhouse gas emissions from the production of soybeans and beef in the Amazon basin of Brazil, a region where rates of both deforestation and agricultural exports are high. Integrating methods from land use science and life-cycle analysis, and accounting for producer‐consumer responsibility, we allocate emissions between Brazil and importing countries with an emphasis on ultimately reducing the greenhouse gas impact of food production. The mechanisms used to distribute the carbon emissions over time allocate the bulk of emissions to the years directly after the land use change occurred, and gradually decrease the carbon allocation to the agricultural products. The carbon liability embodied in soybeans exported from the Amazon between 1990 and 2006 was 128 TgCO2e, while 120 TgCO2e were embodied in exported beef. An equivalent carbon liability was assigned to Brazil for that time period.

Contribution of anaerobic digesters to emissions mitigation and electricity generation under U.S. climate policy.

Livestock husbandry in the U.S. significantly contributes to many environmental problems, including the release of methane, a potent greenhouse gas (GHG). Anaerobic digesters (ADs) break down organic wastes using bacteria that produce methane, which can be collected and combusted to generate electricity. ADs also reduce odors and pathogens that are common with manure storage and the digested manure can be used as a fertilizer. There are relatively few ADs in the U.S., mainly due to their high capital costs. We use the MIT Emissions Prediction and Policy Analysis (EPPA) model to test the effects of a representative U.S. climate stabilization policy on the adoption of ADs which sell electricity and generate methane mitigation credits. Under such policy, ADs become competitive at producing electricity in 2025, when they receive methane reduction credits and electricity from fossil fuels becomes more expensive. We find that ADs have the potential to generate 5.5% of U.S. electricity.

Toward an analytic framework for the electrical power grid

The large majority of electrical power in the United States today is generated from fossil feedstocks. While renewable energy sources offer compelling alternatives, there are many challenges and complexities that currently limit their use. The high-level objective of our work is to create an analytic framework to provide decision support for renewable energy use in electrical power generation in the US. For security reasons, many of the details of the infrastructure that would facilitate our work are not openly available. Thus, we seek to infer key properties of the power generation and transmission infrastructures, using alternative data sources and recognizing that grid dynamics are constrained by federal regulation and the laws of physics. In this discussion paper we describe the design space for our study and our initial analyses of energy pricing data. These data are openly available from Regional Transmission Organizations and Independent System Operators. Our results highlight the complexities and dynamics of the relationships between locations in the power grid, and set the stage for inferring physical and behavioral properties of the power grid.

Steady-State Oxygen Isotope Effects of N2O Production in Paracoccus denitrificans

Knowledge of isotopic discrimination, or fractionation, by denitrifying bacteria can benefit agricultural fertilizer management, wastewater treatment, and other applications. However, the complexity of N transformation pathways in the environment and the sensitivity of denitrification to environmental conditions warrant better isotopic distinction between denitrification and other processes, especially for oxygen isotopes. Here, we present a dataset of δ18O measurements in continuous culture of Paracoccus denitrificans. The authors hope that it will be useful in further studies of N2O in the environment.

Intuitive simulation, querying, and visualization for river basin policy and management

Sustainable use of the freshwater resources of the world is an urgent challenge. The World Health Organization recently estimated that 1.1 billion people lack access to safe drinking water, a problem the United Nations highlights in its Millennium Development Goals. To address the scale and urgency of this challenge, IBM, The Nature Conservancy, and the Center for Sustainability and the Global Environment at the University of Wisconsin-Madison are collaborating to develop innovative, technology-based decision-support tools for improved management of water resources worldwide. The Water for Tomorrow modeling framework and decision support system (DSS) is designed to help policy makers and a variety of stakeholders to assess, come to consensus, and act on land-use decisions that balance human use, ecosystem preservation, and ecosystem restoration. Such stakeholders include farmers, fish and wildlife managers, foodprocessing plant managers, and hydropower operators. Initially focused on the Paraguay-Parana Basin of Brazil, in partnership with local academic and public-sector collaborators, the DSS integrates data and models from a wide variety of environmental sectors, including water balance, water quality, carbon balance, crop production, and proxies for biodiversity. Intuitive interfaces and complex query support allow users to reach a rich understanding of the effect of changes in management on freshwater ecosystems.

Lights Out: Climate Change Risk to Internet Infrastructure

In this paper we consider the risks to Internet infrastructure in the US due to sea level rise. Our study is based on sea level incursion projections from the National Oceanic and Atmospheric Administration (NOAA) [12] and Internet infrastructure deployment data from Internet Atlas [24]. We align the data formats and assess risks in terms of the amount and type of infrastructure that will be under water in different time intervals over the next 100 years. We find that 4,067 miles of fiber conduit will be under water and 1,101 nodes (e.g., points of presence and colocation centers) will be surrounded by water in the next 15 years. We further quantify the risks of sea level rise by defining a metric that considers the combination of geographic scope and Internet infrastructure density. We use this metric to examine different regions and find that the New York, Miami, and Seattle metropolitan areas are at highest risk. We also quantify the risks to individual service provider infrastructures and find that CenturyLink, Inteliquent, and AT&T are at highest risk. While it is difficult to project the impact of countermeasures such as sea walls, our results suggest the urgency of developing mitigation strategies and alternative infrastructure deployments.

Reply to Vermeulen and Wollenberg: Distinguishing food security and crop yields

Vermeulen and Wollenberg (1) caution against interpreting our recent paper (2) as a call to concentrate food production in temperate areas. We did not intend our research to be interpreted as such. As Vermeulen and Wollenberg state, even very low yields can play an extremely important role in providing food security, particularly in low-income tropical countries. We agree that it is important to make the distinction between yields and food security.