By Alexander J Zayac
Prof. Baldwin and Sue Wing Forecast U.S. CO2 Emissions to Exceed Official Estimates in Recent Journal of Regional Science Paper
Recent developments in U.S. climate change policy have seen the first tentative steps toward legislating a binding aggregate emission cap and implementing curbs on GHGs at the state and regional levels.1 This state and regional level policy action has been identified as both a critical element in U.S. emissions reductions and as a force to shape national climate change mitigation policy (Byrne et al., 2007; Lutsey and Sperling, 2008; Rabe, 2008). Consequently, the resulting economic effects of these policies is the subject of intense recent interest (Grainger and Kolstad, 2009; Hassett et al., 2009; Sue Wing, 2010). The first step in making any such assessment, and one incorporated or mandated in all state climate action plans (EPA, 2012), is to forecast how states’ baseline emissions are likely to evolve. Prerequisite to such projections is the ability to characterize the geographic variations in the precursors of GHGs—particularly CO2—based on an understanding of their historical evolution.
In this paper we investigate how the driving forces behind U.S. carbon dioxide emissions have evolved over the period 1963–2008. We take an explicitly spatial approach, quantifying in detail the interregional variations in CO2 precursors that are largely absent in the literature. While several recent papers have exploited state-level databases on the prices and quantities of fuel use, their focus has been quantifying the aggregate effects of drivers such as income and prices.2 The unfortunate consequence is that the substantial interregional heterogeneity underlying these results, which is interesting in its own right, has largely been ignored. An important exception to this general trend is Metcalf’s (2008) inquiry into the drivers of the energy intensity of U.S. states, which he disaggregates into intrasectoral changes in energy efficiency and intersectoral changes in the structure of economic activity. This paper’s key feature is the use of index number decomposition analysis, which is a popular technique for apportioning the time-evolution of a composite variable into contributions associated with movements in its constituent factors.3 We build on this approach, developing an extended decomposition framework which attributes the evolution of CO2 emissions over space and time to five precursors: the emissions intensity of energy use, the energy intensity of economic activity, the composition of states’ output, per capita income and population. Click to read entire paper…
Prof. Myneni’s recent paper in PNAS on CO2 growth rates and tropical temperature
Abstract
Previous studies have highlighted the occurrence and intensity of El Niño–Southern Oscillation as important drivers of the interannual variability of the atmospheric CO2 growth rate, but the underlying biogeophysical mechanisms governing such connections remain unclear. Here we show a strong and persistent coupling (r2 ≈ 0.50) between interannual variations of the CO2 growth rate and tropical land–surface air temperature during 1959 to 2011, with a 1 °C tropical temperature anomaly leading to a 3.5 ± 0.6 Petagrams of carbon per year (PgC/y) CO2 growth-rate anomaly on average. Analysis of simulation results from Dynamic Global Vegetation Models suggests that this temperature–CO2 coupling is contributed mainly by the additive responses of heterotrophic respiration (Rh) and net primary production (NPP) to temperature variations in tropical ecosystems. However, we find a weaker and less consistent (r2 ≈ 0.25) interannual coupling between CO2 growth rate and tropical land precipitation than diagnosed from the Dynamic Global Vegetation Models, likely resulting from the subtractive responses of tropical Rh and NPP to precipitation anomalies that partly offset each other in the net ecosystem exchange (i.e., net ecosystem exchange ≈ Rh − NPP). Variations in other climate variables (e.g., large-scale cloudiness) and natural disturbances (e.g., volcanic eruptions) may induce transient reductions in the temperature–CO2 coupling, but the relationship is robust during the past 50 y and shows full recovery within a few years after any such major variability event. Therefore, it provides an important diagnostic tool for improved understanding of the contemporary and future global carbon cycle. Click for complete PNAS article…
Prof. Myneni’s recent paper in NATURE on asymmetric daytime and night-time warming on vegetation growth
Temperature data over the past five decades show faster warming of the global land surface during the night than during the day1. This asymmetric warming is expected to affect carbon assimilation and consumption in plants, because photosynthesis in most plants occurs during daytime and is more sensitive to the maximum daily temperature, Tmax, whereas plant respiration occurs throughout the day2 and is therefore influenced by both Tmax and the minimum daily temperature, Tmin. Most studies of the response of terrestrial ecosystems to climate warming, however, ignore this asymmetric forcing effect on vegetation growth and carbon dioxide (CO2) fluxes3, 4, 5, 6. Here we analyse the interannual covariations of the satellite-derived normalized difference vegetation index (NDVI, an indicator of vegetation greenness) with Tmax and Tmin over the Northern Hemisphere. After removing the correlation between Tmax and Tmin, we find that the partial correlation between Tmax and NDVI is positive in most wet and cool ecosystems over boreal regions, but negative in dry temperate regions. In contrast, the partial correlation between Tmin and NDVI is negative in boreal regions, and exhibits a more complex behaviour in dry temperate regions. We detect similar patterns in terrestrial net CO2 exchange maps obtained from a global atmospheric inversion model. Additional analysis of the long-term atmospheric CO2 concentration record of the station Point Barrow in Alaska suggests that the peak-to-peak amplitude of CO2 increased by 23 ± 11% for a +1 °C anomaly in Tmax from May to September over lands north of 51° N, but decreased by 28 ± 14% for a +1 °C anomaly in Tmin. These lines of evidence suggest that asymmetric diurnal warming, a process that is currently not taken into account in many global carbon cycle models, leads to a divergent response of Northern Hemisphere vegetation growth and carbon sequestration to rising temperatures. Click for complete article…
Professor Hutyra Nominated to NACP Scientific Steering Committee
he North American Carbon Program (NACP) is a multidisciplinary research program to obtain scientific understanding of North America’s carbon sources and sinks and of changes in carbon stocks needed to meet societal concerns and to provide tools for decision makers. Successful execution of the NACP will require an unprecedented level of coordination among observational, experimental, and modeling efforts regarding terrestrial, oceanic, atmospheric, and human components. The NACP is supported by a number of different federal agencies through a variety of intramural and extramural funding mechanisms and award instruments. NACP will rely upon a rich and diverse array of existing observational networks, monitoring sites, and experimental field studies in North America and its adjacent oceans. Integrating these different program activities and maximizing synergy amongst them, will require expert guidance beyond the norm for large field programs in Earth system science and global climate change.
Click for the NACP website…
Rita Cabral – First Author In Nature Paper
Anomalous Sulphur Isotopes in Plume Lavas Reveal Deep Mantle Storage of Archaean Crust
Basaltic lavas erupted at some oceanic intraplate hotspot volcanoes are thought to sample ancient subducted crustal materials1, 2. However, the residence time of these subducted materials in the mantle is uncertain and model-dependent3, and compelling evidence for their return to the surface in regions of mantle upwelling beneath hotspots is lacking. Here we report anomalous sulphur isotope signatures indicating mass-independent fractionation (MIF) in olivine-hosted sulphides from 20-million-year-old ocean island basalts from Mangaia, Cook Islands (Polynesia), which have been suggested to sample recycled oceanic crust3, 4. Continue reading at Nature.com…
Professor Anderson – Why The Earth Is Warming
Bruce Anderson didn’t set out to prove that the rise in global temperatures since the start of the Industrial Revolution is caused by human activity. And the five-year study that he and four colleagues then published in the October 2012 Journal of Climate doesn’t draw that conclusion, but it does suggest that man-made pollutants are to blame.
The study, which tested three hypotheses about causes of the warming trend, debunks alternative theories that have been floated in recent years. At the same time, says Anderson, a College of Arts & Sciences associate professor of earth and environment, the research strengthens the theory that humans are responsible for the phenomenon, in which carbon dioxide, methane, nitrous oxide, and the other gases we emit accumulate in the atmosphere, trapping the heat that radiates from the Earth.
Click for entire article and video…
Professor Myneni – Tracking Change, Predicting Trouble
Winter is getting warmer, spring is coming earlier, and plants are enjoying an extended growing season in northern areas. But that is not good news. In this weeklong series, BU researchers explore the science behind Earth’s environmental changes, and what they mean for our future.
“It’s the initial gold rush,” says Ranga Myneni, a College of Arts & Science professor of earth and environment, but what will follow will not be pleasant. As vegetation flourishes, it could draw down the water supply, bringing on drought, insect infestations, and forest fires. What was once green, lush land could become brown and barren.
In an article published in Nature Climate Change on March 10, Myneni and 21 collaborators describe how seasonal temperatures and vegetation north of the U.S.-Canada border have shifted over the past 30 years to what is typically experienced four to seven degrees latitude to the south. Should global warming continue at its current pace, Bruce Anderson, a CAS associate professor of earth and environment, who worked with Myneni on the paper, predicts a further latitudinal shift of as much as 20 degrees south by the end of the century. That means arctic and boreal regions of Canada would look and feel much more like the southern United States.
Click for entire article…
Professor Fulweiler’s Message in a Bottle
BU prof: estuary mud tells dire eco-story
For ecologist and biogeochemist Robinson “Wally” Fulweiler, every pungent vial of coastal muck tells a story. Meticulously pieced together in a laboratory that mimics nature, that story is alarming. As she explains, the life-sustaining chemical balance of the planet’s coastal ecosystems is changing dramatically, a result of ever-climbing levels of nitrogen and phosphorous from soil erosion, mining, urban waste, and synthetic fertilizers. In the coastal estuaries and marshes of the Massachusetts shore, Fulweiler, a College of Arts & Sciences assistant professor of earth and environment and of biology, is charting the impact of this destruction, hoping that her findings will raise an alarm about the need to protect these marine resources from further harm.
From the tidal flats of Plum Island to the National Estuarine Research Reserve at Waquoit Bay in Falmouth, she is, in every sense, knee-deep in experiments probing changes in a range of marine nutrients along the Bay State coast. But her lab’s general mission, its “connecting theme,” as she puts it, is the ways that humans have altered coastal systems. From industrial pollution to sewage contamination to straining of resources, the list is long, and much of the damage irreversible, says Fulweiler, whose research focuses on global as well as local impacts of environmental change.
Funded by the National Science Foundation and Sea Grant, a program underwritten by the National Oceanic and Atmospheric Administration, Fulweiler’s work led her and several colleagues to create “The Eutrophication Commandments,” an environmental manifesto published this year in Marine Pollution Bulletin. Commandment number one: “Thou shall protect coastal ecosystems to deliver biodiversity and ecological services.” Click for full article and video on BU Today…
Professor Bruce Anderson appointed to serve on Steering Committee for US Climate Research
Professor Bruce Anderson appointed to serve on the Scientific Steering Committee for the US Climate Variability and Predictability (CLIVAR) Program.
In addition, Prof. Anderson has been appointed as co-chair of the U.S. CLIVAR Predictability, Prediction and Applications Interface Panel. US CLIVAR is responsible for facilitating the development of important climate research efforts in the US. Over the next two years, the Program is embarking on an effort to develop a new US CLIVAR Science Plan to set goals and objectives guiding the U.S. climate research directions for the coming 15 years. In addition, it fosters improved practices in the dissemination and use of climate information and forecasts within the US and international communities. CLIVAR itself is an international, interdisciplinary research effort within the World Climate Research Programme (WCRP) designed to facilitate analysis and prediction of Earth system variability and change for use in an increasing range of practical applications of direct relevance, benefit and value to society.