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Dahowski R.T.,Pacific Northwest National Laboratory | Davidson C.L.,Pacific Northwest National Laboratory | Dooley J.J.,Joint Global Change Research Institute
Energy Procedia | Year: 2011

The United States and China are the two largest emitters of greenhouse gases in the world and their projected continued growth and reliance on fossil fuels - especially coal - make them strong candidates for the large-scale deployment of carbon dioxide capture and storage (CCS) systems in a greenhouse gas constrained world. Previous work has revealed that both nations have over 1600 large electric utility and other industrial point CO 2 sources as well as very large CO 2 storage resources on the order of 2000 billion metric tons (Gt) of onshore storage capacity. In each case, the vast majority of this capacity is found in deep saline formations. In both the USA and China, candidate storage reservoirs are likely to be widely accessible with over 80% of these large industrial CO 2 sources having a CO 2 storage option within just 80 km. This suggests a strong potential for CCS to help bring about meaningful, sustained CO 2 emissions reductions for these large, vibrant economies. However, while the USA and China possess many similarities with regards to the potential value that CCS might provide, including the range of costs at which CCS may be available to most large CO 2 sources in each nation, there are a number of more subtle differences that may help us to understand the ways in which CCS deployment may differ as the the two nations work together - and in step with the rest of the world - to most efficiently reduce greenhouse gas emissions. This paper details the first ever analysis of CCS deployment costs in these two countries based on methodologically comparable CO 2 source and sink inventories, economic analysis, geospatial source-sink matching and cost curve modeling. This type of analysis provides valuable insight into the degree to which early and sustained opportunities for climate change mitigation via commercial-scale CCS are available to the two countries, and could facilitate greater collaboration in areas where those opportunities overlap. © 2011 Published by Elsevier Ltd.


Davidson C.L.,Pacific Northwest National Laboratory | Dahowski R.T.,Pacific Northwest National Laboratory | Dooley J.J.,Joint Global Change Research Institute
Energy Procedia | Year: 2011

This paper explores the impact of the temporally dynamic demand for CO 2 for CCS-coupled EOR by evaluating the variable demand for new (i.e., non-recycled) anthropogenic CO 2 within EOR projects and the extent to which EOR-coupled CCS is compatible with the need for baseload CO 2 storage options for large anthropogenic point sources. A profile of CO 2 demand over an assumed EOR project lifetime is applied across two different storage scenarios to illustrate the differences in cost associated with different EOR-coupled CCS configurations. The first scenario pairs a single EOR field with a DSF used to store any CO 2 that is not used to increase oil recovery in the EOR field; the second scenario is designed to minimize storage in the DSF and maximize lower-cost EOR-based storage by bringing multiple EOR projects online over time as the previous project's CO 2 demand declines, making the source's CO 2 available for a subsequent project. Each scenario is evaluated for two facilities, emitting 3 and 6 MtCO 2/y. Annual and lifetime average CO 2 transport and storage costs are presented, and the impact of added capture and compression costs on overall project economics is examined. The research reported here suggests that the cost of implementing a CCS-coupled EOR project will be more than is typically assumed; in many cases a positive price on CO 2 emitted to the atmosphere will be required to motivate deployment of these CO 2-based EOR projects, except in the most idealized cases. The reasons for this conclusion are twofold. First, the costs of capitalizing, operating and monitoring a secondary DSF to provide backup storage for CO 2 not demanded by the EOR operation can cut sharply into EOR revenues. Second, except in cases where a single firm figures both the CO 2 source emissions and the associated EOR recovery on the same balance sheet, the oil production company is not likely to share a significant portion of revenues from the EOR field with the CO 2 source. Thus, while EOR-coupled CCS may offer attractive early opportunities, these opportunities are likely only available to a small fraction of the CO 2 source fleet in the U.S. © 2011 Published by Elsevier Ltd.


Diplomats gathering in the French capital next week face a tall task in trying to unite 190-plus countries behind a plan to fight climate change. Yet a success in Paris may not, by itself, be enough to prevent dangerous warming of the planet in the decades to come, a new study warns. The report in the journal Science suggests that the Earth can avoid the most disruptive impacts of climate change only if the Paris agreement is a first step, followed by more ambitious cuts in greenhouse-gas pollution in future years. In fact, without further emissions reductions, there is “virtually no chance” that global temperatures will stay below the threshold that many scientists say is safe — a maximum increase of 2 degrees Celsius (3.6 degrees Fahrenheit) over pre-industrial averages, the authors said. The release of the report comes four days before the start of the Paris talks, when world leaders will try to cement an international accord to stop the sharp rise in atmospheric levels of carbon dioxide and other heat-trapping gases from fossil-fuel burning. More than 150 countries have announced pledges to reduce or scale back emissions through the year 2030. U.S. officials have acknowledged that pledges aren’t enough to ensure that the temperatures remain below the 2-degree mark. In the Science study, a team of 15 researchers sought to calculate the odds for keeping the Earth’s temperatures below that threshold, using different scenarios ranging from no further pollution cuts to aggressive and continuing steps to ratchet back on emissions. In an optimistic case — assuming countries honor their Paris commitments and continue to make further pollution cuts — the chances of holding the temperature rise to below 2 degrees improves, but only to about 30 percent, the study found. Real success depends on a “robust process that allows pledges to be progressively tightened over time,” said the researchers, a group of U.S. government scientists and academics from the University of Maryland and other institutions in the United States and Austria. “It is important to note that this round of [pledges] that countries are submitting only extend through 2025 or 2030,” said Allen Fawcett, a government economist and the lead author of the study. While success in Paris will “reduce the probabilities of extreme warming,” the treaty must be followed by “further post-2030 reductions that would improve the odds” of meeting the 2-degree goal, he said. The researchers found that, in order to ensure a strong likelihood of keeping temperature rise in a moderate range, nations will eventually have to achieve a “net-zero” or even “negative” emissions, meaning future emissions are offset by capturing the excess carbon through re-forestation or through new technologies that prevent greenhouse gases from entering the atmosphere. The idea is to deploy carbon-capture technologies on a scale “greater than, or equal to the amount emitted from all other sources,” said Gokul Iyer, the study’s lead scientist at the Joint Global Change Research Institute, a collaboration between the Department of Energy’s Pacific Northwest National Laboratory and the University of Maryland “These scenarios include rapid emissions reductions beyond 2030 phasing out fossil fuels, and many also include negative global emissions in the second half of the century,” he said.


News Article | November 27, 2015
Site: news.yahoo.com

The "Earth Crisis" globe is displayed by US artist Shepard Fairey on the Eiffel tower in Paris, as part of the Conference on Climate Change on November 25, 2015 (AFP Photo/Kenzo Tribouillard) More Washington (AFP) - Pledges made in the lead-up to next week's major Paris climate change conference could limit severe warming, but only if countries turn their words into long-term action, a study said. The crunch UN summit will be officially opened by more than 150 heads of state and government on Monday, making it the biggest gathering of world leaders on climate in history. Negotiators are tasked with sealing a deal that will cap average global warming at two degrees Celsius (3.6 degrees Fahrenheit) over pre-Industrial Revolution levels . In the build-up to Paris, countries announced the contributions that they are willing to make to combat global climate change, based on their own national circumstances. These Intended Nationally Determined Contributions, or INDCs, extend through 2025 or 2030 and will form the backbone of the universal climate-rescue pact. "If countries implement their INDCs through 2030 and ramp up efforts beyond 2030, we'll have a much better chance of avoiding extreme warming and keeping temperature change below two-degrees Celsius," said Gokul Iyer. Iyer was the lead scientist of the study, which was published in the journal Science. "It's important to know that the INDCs are a stepping stone to what we can do in the future," added Iyer, of the Joint Global Change Research Institute, a collaboration between the US Department of Energy's Pacific Northwest National Laboratory and the University of Maryland. Ken Kimmell, president of the Union of Concerned Scientists, a non-profit group, said the Paris meeting was a mixed bag. "This is the first time since climate negotiations started two decades ago that virtually all the world’s nations have committed to being part of the solution," he said. By comparison, the 1997 Kyoto Protocol included pledges for reductions by just 37 countries and comprising well under half of global emissions. But he added: "The Paris agreement is not expected to bind countries to meet their pledges, nor provide for a sanction if they do not. "This is of course disappointing, but there seems to be no way around it."


News Article | February 24, 2017
Site: www.prweb.com

A recent scientific paper by a University of Maryland-led international team of distinguished scientists, including five members of the National Academies, argues that there are critical two-way feedbacks missing from current climate models that are used to inform environmental, climate, and economic policies. The most important inadequately-modeled variables are inequality, consumption, and population. In this research, the authors present extensive evidence of the need for a new paradigm of modeling that incorporates the feedbacks that the Earth system has on humans, and propose a framework for future modeling that would serve as a more realistic guide for policy making and sustainable development. The large, interdisciplinary team of 20 coauthors are from a number of universities (University of Maryland, Northeastern University, Columbia University, George Mason University, Johns Hopkins University, and Brown University) and other institutions (Joint Global Change Research Institute, University Corporation for Atmospheric Research, the Institute for Global Environment and Society, Japan’s RIKEN research institute, and NASA’s Goddard Space Flight Center). The study explains that the Earth System (e.g., atmosphere, ocean, land, and biosphere) provides the Human System (e.g., humans and their production, distribution, and consumption) not only the sources of its inputs (e.g., water, energy, biomass, and materials) but also the sinks (e.g., atmosphere, oceans, rivers, lakes, and lands) that absorb and process its outputs (e.g., emissions, pollution, and other wastes). Titled "Modeling Sustainability: Population, Inequality, Consumption, and Bidirectional Coupling of the Earth and Human Systems", the article describes how the recent rapid growth in resource use, land-use change, emissions, and pollution has made humanity the dominant driver of change in most of the Earth’s natural systems, and how these changes, in turn, have critical feedback effects on humans with costly and serious consequences, including on human health and well-being, economic growth and development, and even human migration and societal conflict. However, the paper argues that these two-way interactions ("bidirectional coupling") are not included in the current models. The Oxford University Press's multidisciplinary journal National Science Review, which published the paper, also highlighted the paper in a separate "Research Highlight", pointing out that "the rate of change of atmospheric concentrations of CO2, CH4, and N2O [the primary greenhouse gases] increased by over 700, 1000, and 300 times (respectively) in the period after the Green Revolution when compared to pre-industrial rates." See attached figure. "Many datasets, for example, the data for the total concentration of atmospheric greenhouse gases, show that human population has been a strong driver of the total impact of humans on our planet Earth. This is seen particularly after the two major accelerating regime shifts: Industrial Revolution (~1750) and Green Revolution (~1950)" said Safa Motesharrei, UMD systems scientist and lead author of the paper. "For the most recent time, we show that the total impact has grown on average ~4 percent between 1950 and 2010, with almost equal contributions from population growth (~1.7 percent) and GDP per capita growth (~2.2 percent). This corresponds to a doubling of the total impact every ~17 years. This doubling of the impact is shockingly rapid." "However, these human impacts can only truly be understood within the context of economic inequality,” pointed out political scientist and co-author Jorge Rivas of the Institute for Global Environment and Society. "The average per capita resource use in wealthy countries is 5 to 10 times higher than in developing countries, and the developed countries are responsible for over three quarters of cumulative greenhouse gas emissions from 1850 to 2000." "The disparity is even greater when inequality within countries is included," added University of Maryland geographer and coauthor Klaus Hubacek. "For example, about 50 percent of the world’s people live on less than $3 per day, 75 percent on less than $8.50, and 90 percent on less than $23. One effect of this inequality is that the top 10 percent produce almost as much total carbon emissions as the bottom 90 percent combined." The study explains that increases in economic inequality, consumption per capita, and total population are all driving this rapid growth in human impact, but that the major scientific models of Earth-Human System interaction do not bidirectionally couple Earth System Models with the primary Human System drivers of change such as demographics, inequality, economic growth, and migration. Instead of two-way coupling with these primary human drivers of change, the researchers argue that current models usually use independent, external projections of those drivers. "This lack of two-way coupling makes current models likely to miss critical feedbacks in the combined Earth-Human system", said National Academy of Engineering member and co-author Eugenia Kalnay, a Distinguished University Professor of Atmospheric and Oceanic Science at the University of Maryland. "It would be like trying to predict El Niño with a sophisticated atmospheric model but with the Sea Surface Temperatures taken from external, independent projections by, for example, the United Nations. Without including the real feedbacks, predictions for coupled systems cannot work; the model will get away from reality very quickly," said Kalnay In this new scientific research, the authors present extensive evidence of the need for a new paradigm of modeling that incorporates the feedbacks that the Earth System has on humans, and propose a framework for future modeling that would serve as a more realistic guide for policymaking and sustainable development. "Ignoring this bidirectional coupling of the Earth and Human Systems can lead to missing something important, even decisive, for the fate of our planet and our species," said co-author Mark Cane, G. Unger Vetlesen Professor of Earth and Climate Sciences at Columbia University’s Lamont-Doherty Earth Observatory, who recently won the Vetlesen Prize for creating the first coupled ocean–atmosphere model with feedbacks that successfully predicted El Niño. "The result of not dynamically modeling these critical Human-Earth System feedbacks would be that the environmental challenges humanity faces may be significantly underestimated. Moreover, there’s no explicit role given to policies and investments to actively shape the course in which the dynamics unfold. Rather, as the models are designed now, any intervention — almost by definition — comes from the outside and is perceived as a cost," said co-author Matthias Ruth, Director and Professor at the School of Public Policy and Urban Affairs, Northeastern University. "Such modeling, and the mindset that goes with it, leaves no room for creativity in solving some of the most pressing challenges." ''The paper correctly highlights that other human stressors, not only the climate ones, are very important for long-term sustainability, including the need to reduce inequality'', said Carlos Nobre (not a co-author), one of the world’s leading Earth System scientists, who recently won the prestigious Volvo Environment Prize in Sustainability for his role in understanding and protecting the Amazon. ''Social and economic equality empowers societies to engage in sustainable pathways, which includes, by the way, not only the sustainable use of natural resources but also slowing down population growth, to actively diminish the human footprint on the environment.'' Michael Mann, Distinguished Professor and Director of the Earth System Science Center at Penn State University, who is not a co-author of the paper, commented: "We cannot separate the issues of population growth, resource consumption, the burning of fossil fuels, and climate risk. They are part of a coupled dynamical system, and, as the authors show, this has dire potential consequences for societal collapse. The implications couldn’t be more profound." This work was supported by the University of Maryland Council on the Environment 2014 Seed Grant (1357928). The authors would like to acknowledge the following grants and institutions: SM, KF, and KH: National Socio-Environmental Synthesis Center (SESYNC)--US National Science Foundation (NSF) award DBI-1052875; JR: The Institute of Global Environment and Society (IGES); GRA: Laboratory Directed Research and Development award by the Pacific Northwest National Laboratory, which is managed by the Battelle Memorial Institute for the US Department of Energy; MAC: Office of Naval Research, research grant MURI N00014-12-1-0911; FMW: NSF award CBET-1541642; VMY: The Institute for New Economic Thinking (INET). "Modeling Sustainability: Population, Inequality, Consumption, and Bidirectional Coupling of the Earth and Human Systems" is available at: https://academic.oup.com/nsr/article/doi/10.1093/nsr/nww081/2669331/Modeling-Sustainability-Population-Inequality and https://doi.org/10.1093/nsr/nww081; or PDF https://academic.oup.com/nsr/article-pdf/3/4/470/10325470/nww081.pdf


News Article | February 17, 2017
Site: www.eurekalert.org

COLLEGE PARK, Md. - A new scientific paper by a University of Maryland-led international team of distinguished scientists, including five members of the National Academies, argues that there are critical two-way feedbacks missing from current climate models that are used to inform environmental, climate, and economic policies. The most important inadequately-modeled variables are inequality, consumption, and population. In this research, the authors present extensive evidence of the need for a new paradigm of modeling that incorporates the feedbacks that the Earth System has on humans, and propose a framework for future modeling that would serve as a more realistic guide for policymaking and sustainable development. Twelve of the interdisciplinary team of 20 coauthors are from the University of Maryland, with multiple other universities (Northeastern University, Columbia University, George Mason University, Johns Hopkins University, and Brown University) and other institutions (Joint Global Change Research Institute, University Corporation for Atmospheric Research, the Institute for Global Environment and Society, Japan's RIKEN research institute, and NASA's Goddard Space Flight Center) also represented. The study explains that the Earth System (e.g., atmosphere, ocean, land, and biosphere) provides the Human System (e.g., humans and their production, distribution, and consumption) not only the sources of its inputs (e.g., water, energy, biomass, and materials) but also the sinks (e.g., atmosphere, oceans, rivers, lakes, and lands) that absorb and process its outputs (e.g., emissions, pollution, and other wastes). Titled "Modeling Sustainability: Population, Inequality, Consumption, and Bidirectional Coupling of the Earth and Human Systems", the paper describes how the rapid growth in resource use, land-use change, emissions, and pollution has made humanity the dominant driver of change in most of the Earth's natural systems, and how these changes, in turn, have critical feedback effects on humans with costly and serious consequences, including on human health and well-being, economic growth and development, and even human migration and societal conflict. However, the paper argues that these two-way interactions ("bidirectional coupling") are not included in the current models. The Oxford University Press's multidisciplinary journal National Science Review, which published the paper, has highlighted the work in its current issue, pointing out that "the rate of change of atmospheric concentrations of CO2, CH4, and N2O [the primary greenhouse gases] increased by over 700, 1000, and 300 times (respectively) in the period after the Green Revolution when compared to pre-industrial rates." See Figure 1 from the Highlights article, reproduced below. "Many datasets, for example, the data for the total concentration of atmospheric greenhouse gases, show that human population has been a strong driver of the total impact of humans on our planet Earth. This is seen particularly after the two major accelerating regime shifts: Industrial Revolution (~1750) and Green Revolution (~1950)" said Safa Motesharrei, UMD systems scientist and lead author of the paper. "For the most recent time, we show that the total impact has grown on average ~4 percent between 1950 and 2010, with almost equal contributions from population growth (~1.7 percent) and GDP per capita growth (~2.2 percent). This corresponds to a doubling of the total impact every ~17 years. This doubling of the impact is shockingly rapid." "However, these human impacts can only truly be understood within the context of economic inequality," pointed out political scientist and co-author Jorge Rivas of the Institute for Global Environment and Society. "The average per capita resource use in wealthy countries is 5 to 10 times higher than in developing countries, and the developed countries are responsible for over three quarters of cumulative greenhouse gas emissions from 1850 to 2000." University of Maryland geographer and co-author Klaus Hubacek added: "The disparity is even greater when inequality within countries is included. For example, about 50 percent of the world's people live on less than $3 per day, 75 percent on less than $8.50, and 90 percent on less than $23. One effect of this inequality is that the top 10 percent produce almost as much total carbon emissions as the bottom 90 percent combined." The study explains that increases in economic inequality, consumption per capita, and total population are all driving this rapid growth in human impact, but that the major scientific models of Earth-Human System interaction do not bidirectionally (interactively) couple Earth System Models with the primary Human System drivers of change such as demographics, inequality, economic growth, and migration. The researchers argue that current models instead generally use independent, external projections of those drivers. "This lack of two-way coupling makes current models likely to miss critical feedbacks in the combined Earth-Human system," said National Academy of Engineering member and co-author Eugenia Kalnay, a Distinguished University Professor of Atmospheric and Oceanic Science at the University of Maryland. "It would be like trying to predict El Niño with a sophisticated atmospheric model, but with the Sea Surface Temperatures taken from external, independent projections by, for example, the United Nations," said Kalnay. "Without including the real feedbacks, predictions for coupled systems cannot work; the model will get away from reality very quickly." "Ignoring this bidirectional coupling of the Earth and Human Systems can lead to missing something important, even decisive, for the fate of our planet and our species," said co-author Mark Cane, G. Unger Vetlesen Professor of Earth and Climate Sciences at Columbia University's Lamont-Doherty Earth Observatory, who recently won the Vetlesen Prize for creating the first coupled ocean-atmosphere model with feedbacks that successfully predicted El Niño. Co-author Matthias Ruth, Director and Professor at the School of Public Policy and Urban Affairs, Northeastern University, said: "The result of not dynamically modeling these critical Human-Earth System feedbacks would be that the environmental challenges humanity faces may be significantly underestimated. Moreover, there's no explicit role given to policies and investments to actively shape the course in which the dynamics unfold. Rather, as the models are designed now, any intervention -- almost by definition -- comes from the outside and is perceived as a cost. Such modeling, and the mindset that goes with it, leaves no room for creativity in solving some of the most pressing challenges." "The paper correctly highlights that other human stressors, not only the climate ones, are very important for long-term sustainability, including the need to reduce inequality'', said Carlos Nobre (not a co-author), one of the world's leading Earth System scientists, who recently won the prestigious Volvo Environment Prize in Sustainability for his role in understanding and protecting the Amazon. "Social and economic equality empowers societies to engage in sustainable pathways, which includes, by the way, not only the sustainable use of natural resources but also slowing down population growth, to actively diminish the human footprint on the environment." Michael Mann, Distinguished Professor and Director of the Earth System Science Center at Penn State University, who was not a co-author of the paper, commented: "We cannot separate the issues of population growth, resource consumption, the burning of fossil fuels, and climate risk. They are part of a coupled dynamical system, and, as the authors show, this has dire potential consequences for societal collapse. The implications couldn't be more profound." This work was supported by the University of Maryland Council on the Environment 2014 Seed Grant (1357928). The authors would like to acknowledge the following grants and institutions: SM, KF, and KH: National Socio-Environmental Synthesis Center (SESYNC)--US National Science Foundation (NSF) award DBI-1052875; JR: The Institute of Global Environment and Society (IGES); GRA: Laboratory Directed Research and Development award by the Pacific Northwest National Laboratory, which is managed by the Battelle Memorial Institute for the US Department of Energy; MAC: Office of Naval Research, research grant MURI N00014-12-1-0911; FMW: NSF award CBET-1541642; VMY: The Institute for New Economic Thinking (INET). "Modeling Sustainability: Population, Inequality, Consumption, and Bidirectional Coupling of the Earth and Human Systems" is available at: https:/ and https:/ or PDF https:/


News Article | November 25, 2015
Site: www.nature.com

The year is 2100 and the world looks nothing like it did when global leaders gathered for the historic climate summit in Paris at the end of 2015. Nearly 8.8 billion people now crowd the planet. Energy consumption has nearly doubled, and economic production has increased more than sevenfold. Vast disparities in wealth remain, but governments have achieved one crucial goal: limiting global warming to 2 °C above pre-industrial temperatures. The United Nations meeting in Paris proved to be a turning point. After forging a climate treaty, governments immediately moved to halt tropical deforestation and to expand forests around the globe. By 2020, plants and soils were stockpiling more than 17 billion tonnes of extra carbon dioxide each year, offsetting 50% of global CO emissions. Several million wind turbines were installed, and thousands of nuclear power plants were built. The solar industry ballooned, overtaking coal as a source of energy in the waning years of the twenty-first century. But it took more than this. Governments had to drive emissions into negative terri­tory — essentially sucking greenhouse gases from the skies — by vastly increasing the use of bioenergy, capturing the CO generated and then pumping it underground on truly massive scales. These efforts pulled Earth back from the brink. Atmospheric CO concentrations peaked in 2060, below the target of 450 parts per million (p.p.m.) and continue to fall. That scenario for conquering global warming is one possible — if optimistic — vision of the future. It was developed by modellers at the Joint Global Change Research Institute in College Park, Maryland, as part of a broad effort by climate scientists to chart possible paths for limiting global warming to 2 °C, a target enshrined in the UN climate convention that will produce the Paris treaty. Climate modellers have developed dozens of rosy 2 °C scenarios over several years, and these fed into the latest assessment by the Intergovernmental Panel on Climate Change (IPCC). The panel seeks to be policy-neutral and has never formally endorsed the 2-degree target, but its official message, delivered in April 2014, was clear: the goal is ambitious but achievable. This work has fuelled hope among policymakers and environ­mentalists, and it will provide a foundation for debate as governments negotiate a new climate agreement at the UN’s 2015 Paris Climate Conference starting on 30 November. Despite broad agreement that the emissions-reduction commitments that countries have offered up so far are insufficient, policy­makers continue to talk about bending the emissions curve downwards to remain on the path to 2 degrees that was laid out by the IPCC. But take a closer look, some scientists argue, and the 2 °C scenarios that define that path seem so optimistic and detached from current political realities that they verge on the farcical. Although the caveats and uncertainties are all spelled out in the scientific literature, there is concern that the 2 °C modelling effort has distorted the political debate by obscuring the scale of the challenge. In particular, some researchers have questioned the viability of large-scale bioenergy use with carbon capture and storage (CCS), on which many models now rely as a relatively cheap way to provide substantial negative emissions. The entire exercise has opened up a rift in the scientific community, with some people raising ethical questions about whether scientists are bending to the will of politicians and government funders who want to maintain 2 °C as a viable political target. “Nobody dares say it’s impossible,” says Oliver Geden, head of the European Union Research Division at the German Institute for Inter­national and Security Affairs in Berlin. “Everybody is sort of underwriting the 2-degree cheque, but scientists have to think about the credibility of climate science.” Modellers are first to acknowledge the limits of their work, and say that the effort is designed to explore options, not predict the future. “We’ll tell you how many nuclear power plants you need, or how much CCS, but we can’t tell you whether society is going to be willing to do that or not,” says Leon Clarke, a senior scientist and modeller at the Joint Global Change Research Institute. “That’s a different question.” The idea of limiting global warming to 2 °C dates back to 1975, when economist William Nordhaus of Yale University in New Haven, Connecticut, proposed that more than 2 or 3 degrees of warming would push the planet outside the temperature range of the past several hundred thousand years. In 1996, the EU adopted that limit, and the Group of 8 (G8) nations signed on in 2009. The parties to the UN convention on climate change affirmed the target in 2009 at their Copenhagen summit, and then formally adopted it a year later in Cancún, Mexico. The move caught scientists off guard. Before 2009, most modellers had focused on scenarios in which atmospheric CO concentrations stabilized around 550 p.p.m. — double the pre-industrial level — which would probably limit warming to a little less than 3 °C. But as political interest in the 2 °C target grew, a few started exploring the implications. In April 2009, a team led by Myles Allen, a climate scientist at the University of Oxford, UK, published1 a study concluding that humans would have to limit their total cumulative carbon emissions to 1 trillion tonnes — more than half of which had already been dumped into the atmosphere — to maintain a chance of limiting warming to 2 °C. This trillion-tonne carbon budget provided a scientific baseline for what was now a politically important target, and many modellers shifted gears. “There were very few scenarios with stringent targets such as 2 °C, and then sponsors started demanding it,” says Massimo Tavoni, deputy coordinator of climate-change programmes at the Eni Enrico Mattei Foundation in Milan, Italy. The flurry of modelling efforts that followed split into two main camps: pay early or pay late (see ‘Two paths to 2 °C’). In the former, nations need to slash greenhouse-gas emissions immediately; in the latter, they can buy time for a slower phase-out by developing a massive infrastructure to suck CO out of the air. “Models that have these negative emissions really do let you continue to party on now, because you have these options later,” says John Reilly, co-director of the Joint Program on the Science and Policy of Global Change at the Massachusetts Institute of Technology (MIT) in Cambridge. In the pay-later approach, most models rely on a combination of bioenergy and CCS. The system starts with planting crops that are harvested and either processed to make biofuels or burnt to generate electricity, which provide carbon-neutral power because the plants absorb CO as they grow. The CO created when the plants are processed is captured and pumped underground, and the process as a whole eats up more emissions than it creates. A consortium sponsored by the US Department of Energy has tested such a system at one facility that produces bioethanol fuel in Illinois, but neither bioenergy nor CCS has been demonstrated on anywhere near the scales imagined by the models. “It’s just simple arithmetic: the carbon budget is so small that you need to go negative, or at least you need to offset some of your emissions in order to get to zero,” says Tavoni. “We tried to be honest, and pretty agnostic about whether these transformations are easily achievable.” On the basis of those models and other information, the IPCC estimates that climate mitigation would reduce the projected global consumption in 2100 by 3–11% — a relatively modest amount that would allow the global economy to keep growing overall. But remove either bioenergy or CCS from the scenarios and the costs increase substantially. If mitigation is delayed or bioenergy and CCS are constrained, most models simply can’t limit warming to 2 °C. The question is whether any of those models accurately reflect technical and social challenges. MIT has a model that tends to project costs two or three times the average reported by the IPCC, in part because it tries to reflect difficulties in scaling up any technology, such as the availability of skilled labour and natural resources in different regions. And then there are the technical hurdles. Capturing CO from power plants has proved more difficult and expensive than many had hoped. Just one commercial project is currently operating, at the Boundary Dam Power Station in Saskatchewan, Canada. Moreover, Reilly says, the number of models that actually completed 2 °C scenarios remains relatively small, and they probably project lower mitigation costs than those that are not able to generate these low-emissions scenarios. “It’s a very self-selecting set of models.” Although the caveats are listed in the IPCC assessment, the report does not adequately highlight economic and technical challenges or modelling uncertainties, says David Victor, a political scientist at the University of California, San Diego, who participated in the IPCC assessment. Victor does not place all the blame on scientists glossing over the problems: when researchers drafted the assessment’s chapter on emissions scenarios and costs, he says, they included clear statements about the difficulty of achieving the 2 °C goal. But the governments — led by the EU and a bloc of developing countries — pushed for a more optimistic assessment in the final IPCC report. “We got a lot of pushback, and the text basically got mangled,” Victor says. For all of the concerns and criticisms, however, modellers say that the exercises have illuminated important research questions, such as how much bioenergy and CCS will cost and what effects they will have on land use, food systems and water availability. One 2014 study2 in Earth’s Future, for instance, found that it would be difficult to grow enough bioenergy crops, even with second-generation cellulosic biofuels, which are made not only from a plant’s sugars but also from the carbon in its stem and woody materials. The effort would require significant boosts in crop yields and the use of 77% more nitrogen fertilizer by 2100. The bio­energy would also need to be produced in centralized facilities that capture the bulk of the emissions. Unless everything goes right, scaling up to the level projected in many models would be difficult without significantly reducing food production or clearing large swathes of natural ecosystems for farmland. “If we need to ramp up such a large infrastructure, we need to investigate what that implies,” says Sabine Fuss, an environmental scientist at the Mercator Research Institute on Global Commons and Climate Change in Berlin. Fuss led a commentary3 in Nature Climate Change in October 2014 calling for a transdisciplinary research agenda on negative emissions. One of the first outgrowths of that work, led by co-author Peter Smith, a biologist at the University of Aberdeen, UK, is an upcoming assessment of carbon-negative strategies and potential limitations. Strategies include bioenergy with CCS, as well as other ways of absorbing carbon, such as planting forests, using chemical scrubbers to capture CO directly from the air and crushing rocks to enhance geological weathering that consumes the gas. “The science behind these technologies is probably a bit behind the models,” Smith says. “This sort of provides a road map for where we need to go in the next two or three years.” Modellers are also digging into real-world complexities. Most models assume that participation in climate mitigation will be global, that countries will put a common price on carbon, that technological solutions will be widely available and that this combination will drive investment towards relatively cheap mitigation options in developing nations. But the reality could be more complicated. A team at the Joint Global Change Research Institute worked with Victor and others to investigate the risks of making investments in developing countries due to political instability and the relatively poor quality of many public institutions there. Their model showed4 that investors would probably shun developing countries and pour money into developed ones, driving up costs and making it harder to curb rapidly rising emissions in developing nations. “The models have taught us that with unrealistic assumptions anything is possible, and with realistic assumptions it will be very hard to cut emissions to meet goals like 2 degrees,” Victor says. “That’s an important result because it forces — or should force — some sobriety about what can be achieved.” One message that modellers have delivered quite clearly is that without collective and aggressive action by all countries, costs invariably increase, and the chance of hitting the 2 °C goal plummets. This is precisely the situation heading into the Paris summit. Most countries, and all of the major greenhouse-gas emitters, have submitted pledges to reduce their emissions, but these vary widely in ambition. As it stands, the world is on a path to nearly 3 °C of warming by the end of the century, and even that assumes substantial emissions reductions in the future. If nations do not go beyond their Paris pledges, the world could be on track to use up its 2 °C carbon budget as early as 2032. If the models are correct, world leaders may have to either accept extra warming or plan for a Herculean negative-emissions campaign. In the event that they choose the latter — and succeed — the entire debate will change. “It’s a completely different game,” says Nebojsa Nakicenovic, an economic modeller and deputy director-general of the International Institute for Applied Systems Analysis in Laxenburg, Austria. “If that is technically possible, then we could also go below 2 degrees.” Fast-forward to 2100 once more. The bioenergy industry is now one of the largest and most powerful on Earth. People are pulling roughly as much CO out of the atmosphere as they were emitting at the time of the historic Paris conference. Humanity has asserted control over the atmosphere, and governments face a new and difficult question at the 108th anniversary of the UN climate convention: how low should they set the global thermostat?


Kim S.H.,Joint Global Change Research Institute | Wada K.,Japan Research Institute of Innovative Technology for the Earth | Kurosawa A.,Japan Institute of Applied Energy | Roberts M.,Stanford University
Climatic Change | Year: 2014

The nuclear energy response for mitigating global climate change across 18 participating models of the EMF27 study is investigated. Diverse perspectives on the future role of nuclear power in the global energy system are evident in the broad range of nuclear power contributions from participating models of the study. In the Baseline scenario without climate policy, nuclear electricity generation and shares span 0-66 EJ/year and 0-25 % in 2100 for all models, with a median nuclear electricity generation of 39 EJ/year (1,389 GWe at 90 % capacity factor) and median share of 9 %. The role of nuclear energy increased under the climate policy scenarios. The median of nuclear energy use across all models doubled in the 450 ppm CO2e scenario with a nuclear electricity generation of 67 EJ/year (2,352 GWe at 90 % capacity factor) and share of 17 % in 2100. The broad range of nuclear electricity generation (11-214 EJ/year) and shares (2-38 %) in 2100 of the 450 ppm CO2e scenario reflect differences in the technology choice behavior, technology assumptions and competitiveness of low carbon technologies. Greater clarification of nuclear fuel cycle issues and risk factors associated with nuclear energy use are necessary for understanding the nuclear deployment constraints imposed in models and for improving the assessment of the nuclear energy potential in addressing climate change. © 2014 Springer Science+Business Media Dordrecht.


Gregg J.S.,University of Maryland University College | Gregg J.S.,Joint Global Change Research Institute | Izaurralde R.C.,University of Maryland University College | Izaurralde R.C.,Joint Global Change Research Institute
Biofuels | Year: 2010

Background: Agricultural residues could potentially be converted to bioenergy, but the sustainable harvest rate is unclear. Results: Residue removal increases soil loss at rates that vary with topography, crop rotation and management; decreases yields (100-year mean yields changed -0.07 to -0.08% for every percent of residue mass removed); decreases soil carbon (approximately 40-90 kg C ha -1 year -1 per Mg of residue harvested); and decreases soil nitrogen (∼3 kg N ha -1 year -1 per Mg residue harvested). Conclusion: Even where soil loss is within tolerable limits, harvesting residue is a question of trade-offs in terms of reduction of yield and loss of soil nutrients. The effects of increased residue harvest are highly variable, depending on local climate and soil erodibility and it is thus problematic to apply a single harvest rate globally. However, on flat land under conservation management, the majority of residue could be sustainably harvested for bioenergy. © 2010 Future Science Ltd.


Morton D.C.,NASA | Le Page Y.,Joint Global Change Research Institute | DeFries R.,Columbia University | Collatz G.J.,NASA | And 2 more authors.
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2013

Recent drought events underscore the vulnerability of Amazon forests to understorey fires. The long-term impact of fires on biodiversity and forest carbon stocks depends on the frequency of fire damages and deforestation rates of burned forests. Here, we characterized the spatial and temporal dynamics of understorey fires (1999-2010) and deforestation (2001-2010) in southern Amazonia using new satellite-based estimates of annual fire activity (greater than 50 ha) and deforestation (greater than 10 ha). Understorey forest fires burned more than 85 500 km2 between 1999 and 2010 (2.8% of all forests). Forests that burned more than once accounted for 16 per cent of all understorey fires. Repeated fire activity was concentrated in Mato Grosso and eastern Para ́, whereas single fires were widespread across the arc of deforestation. Routine fire activity in Mato Grosso coincided with annual periods of low night-time relative humidity, suggesting a strong climate control on both single and repeated fires. Understorey fires occurred in regions with active deforestation, yet the interannual variability of fire and deforestation were uncorrelated, and only 2.6 per cent of forests that burned between 1999 and 2008were deforested for agricultural use by 2010. Evidence from the past decade suggests that future projections of frontier landscapes in Amazonia should separately consider economic drivers to project future deforestation and climate to project fire risk. © 2013 The Author(s) Published by the Royal Society. All rights reserved.

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