Dorothee C E Bakker

The widespread use of fossil energy results in the release of the greenhouse gas carbon dioxide (CO2) to the atmosphere at an average rate of 5.9 petagrams of carbon per year (PgC yr-1 1 Pg 1015 g) (Sabine et al., Chapter 2, this volume). The resulting rapid increase of atmospheric CO2 is a major factor in global warming (Houghton et al. 2001). Because of the potential risks of climate change, it is crucial to consider how to curb fossil-fuel CO2 emissions and whether techniques are available...

Northern Wetlands Tundra

Northern wetlands and tundra ecosystems exist in the extremely cold desert climate of the Arctic. Yet, they often remain waterlogged during the summer, as the water balance is positive precipitation exceeds evaporation. This combination of factors affects the seasonality and rates of carbon exchange experienced by northern wetlands and tundra (Figure 15.9). Despite extreme cold temperatures during the winter, these ecosystems continue to respire (Vourlitis et al. 2000). Respiration occurs...

Estimating the Size of Terrestrial Carbon Sinks

In most early summaries of the global carbon budget, the size of the terrestrial sink was determined by difference. That is, estimates of land use emissions (typically from Houghton's studies) were subtracted from the net uptake of the terrestrial biosphere inferred from atmospheric measurements (e.g., Table 14.2, Table 14.3). That is, the terrestrial carbon sink was inferred from the difference of other fluxes and was not described explicitly. This is why it was (until recently) usually...

Peter G Brewer

It is now 25 years since Marchetti (1977) first suggested bypassing atmospheric disposal of some fraction of industrial CO2 emissions and using direct deep-ocean disposal as one means of ameliorating climate change. After all, the alkalinity of the ocean already provides the dominant long-term sink for atmospheric CO2, and deep-ocean injection may logically be seen as simply accelerating a natural process. Behind this apparently simple suggestion lies great complexity, fascinating science, and...

Biological Sequestration in the Oceans

In equation (3), this option promotes CO2 uptake in the ocean component of FSq. Ocean Fertilization The efficiency and duration of carbon storage by ocean fertilization remain poorly defined and strongly depend on the oceanic region and fertilizer (iron, nitrogen, phosphorus) used (Bakker, Chapter 26, this volume). The maximum potential of iron fertilization has been estimated as 1 PgC yr-1 by continuous fertilization of all oceanic waters south of 30 S (Valparaiso, Cape Town, Perth) for 100...

Jae Edmonds

The scale of human activities has grown to the point that they affect the Earth's global biogeochemical cycles. The concentrations of greenhouse gases such as carbon dioxide and methane have risen to levels that exceed any observations over very long periods. For CO2 present concentrations exceed observed values over the past 400,000 to 23 million years (Houghton et al. 2001). Fossil-fuel carbon dioxide emissions are chiefly, but not exclusively, associated with the increase in concentration of...

Non FossilFuel Energy Sources

These options reduce f (the fraction of primary energy from fossil fuel) in equation (3). Hydropower At present about 19 percent of the world's electricity is produced from hydropower (McCarthy et al. 2001). Although this source is reaching saturation in developed countries, continued deployment is likely in many developing countries. Hydropower is a renewable energy source with important benefits, such as flood control and regulation of river flows for agricultural, industrial, and urban use....

Ancillary Benefits of CO2 Stabilization Technologies

Probably the single greatest motivation for adopting a new technology is direct cost If it is cheaper than existing technologies it is adopted quickly. Externalities rarely figure into private sector motivations unless encouraged with government incentives or regulatory structures. Nevertheless, a number of mitigation options have ancillary benefits that can substantially multiply their value to GHG mitigation per se. Biosphere sequestration of carbon and mitigation of non-CO2 fluxes are two...

Barriers to Implementation

Engineers frequently adopt the view that if we build it (so that it is cheap and effective) they will come. The reality is that large-scale technology adoption and diffusion are often much more complicated and uncertain. Even when there are no major barriers to adoption, it may take several decades or more for a new technology to become widely used because old capital stock remains economically attractive and personnel are slow to understand and appreciate the benefits of new technology. Beyond...

Uncoupled Simulations

1920 1940 1960 1980 2000 2020 2040 2060 2080 2100 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100 i i i i 1 i i i i 1 i i i i 1 i i i i 1 i i i i 1 i i i IPSL MODEL SRES-A2 SCENARIO 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 IPSL MODEL SRES-A2 SCENARIO 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100 Figure 3.1. Cumulative...

Literature Cited

Nelson, and A. V. Pavlov. 1999. Predictive scenarios of permafrost development under conditions of global climate change in the XXI century. Earth Cryology 3 (4) 15-25. Archer, D., H. Kheshgi, and E. Maier-Reimer. 1997. Multiple timescales for neutralization of fossil fuel CO2. Geophysical Research Letters 24 (4) 405-408. Archer, D., G. Eshel, A. Winguth, and W. Broecker. 2000. Atmospheric CO2 sensitivity to the biological pump in the ocean. GlobalBiogeochemical Cycles 14...

Ronald G Prinn

The atmosphere contains a large number of anthropogenic greenhouse gases besides carbon dioxide, which, because of their rising concentrations, have collectively contributed an amount of added radiative forcing comparable to that of CO2 since prein-dustrial times. Many of these non-CO2 gases (e.g., CH4, N2O, CF2Cl2, SF6) are emitted at the surface and contribute directly to this forcing. They are characterized by atmospheric lifetimes of decades to millennia (I define lifetime here as the...

Population Effects on Food Demand

We calculated 2100 food demand (assumed proportional to population growth) and the increase in productivity for each scenario (Table 6.3b). The area under crops in 1990 represents slightly over a third of the land that is theoretically estimated to be suitable for crop production. Although this estimated area may be optimistic (since some land is not well suited to permanent cropping, and other land will be removed from production by degradation), there is evidence that additional food can be...

Renewables and Noncarbon Energy Sources

Renewable energy sources produced by direct solar capture (photovoltaics), wind, hydro, and biomass are all forms of solar energy. Hence, all sources face a finite upper limit of available energy (Metz et al. 2001 Lightfoot and Green 2002), based on net flux density (e.g., average radiation at the ground of 200 watts per square meter W m-2 ). Biomass production is limited by the photosynthetic efficiency of conversion of solar energy, which on a canopy scale is capped at about 2-3 percent...

Corinne Le Quere and Nicolas Metzl

The oceans hold 50 times more carbon than the atmosphere. The large carbon content of the ocean results from carbon chemistry. When CO2 dissolves in the ocean, it reacts with water and carbonate (CO32-) to form bicarbonate (HCO3-) ions according to the following equilibrium reaction The sum of CO2, HCO3-, and CO32- is called dissolved inorganic carbon (DIC). Ninety-one percent of DIC is in the form of HCO3-, 8 percent in CO32-, and 1 percent in CO2. Only CO2 can exchange with the atmosphere. At...

Nebojsa Nakicenovic

Mvb Pathwy

Numerous factors, sometimes called driving forces, influence future greenhouse gas (GHG) emissions. Both future emissions and the evolution of their underlying driving forces (e.g., rate of technology changes, prices) are highly uncertain. This is the reason scenarios are used to describe how the future may develop, based on a coherent and internally consistent set of assumptions about key relationships, driving forces, and the emissions outcomes. The emissions scenarios in the literature...

Maria Jos Sanz Ernst Detlef Schulze and Riccardo Valentini

Climate change is one of the most significant sustainable development challenges facing the international community. It has implications not only for the health and well-being of the Earth's ecosystems, but also for the economic enterprises and social livelihoods that we have built upon this base. Creative responses based on solid research, shared knowledge, and the engagement of people at all levels are required to meet the challenge posed by climate change. International agreements are one of...

Louis Lebel

To achieve CO2 stabilization in the atmosphere within the next century will require profound social changes in a world where most societies have already become, or aspire to be, carbon cultures. Culture is understood as a critical set of institutions that guide the ideas by which a society lives. Culture penetrates market, political, and other institutions and is far more than a grab-bag for all those factors that are not about economics or politics. In carbon cultures, much behavior and...

Terrestrial Biological Sequestration and Disturbance Reduction

In equation (3), these options reduce emissions from FLULUC and promote CO2 uptake in the land component of FSq. Reforestation, Afforestation, and Land Restoration The potential global carbon sequestration due to increased forest extension and other land uses is in the order of 1 PgC y-1 by 2010 (Watson et al. 2000b). In the past few decades major plantation has occurred in many countries, often where previous deforestation took place. During the 1990s alone, the global area of plantations...

NonCO2 Trace Gas Connections

Scfas And Metabolism

Rising concentrations of a large number of potent anthropogenic greenhouse gases other than carbon dioxide have collectively contributed an amount of radiative forcing comparable to that of CO2 since preindustrial times. Many of these non-CO2 gases (e.g., CH4, N2O, CF2O2, SF6) are emitted at the Earth's surface and contribute directly to this forcing (Prinn, Chapter 9, this volume). They are characterized by atmospheric lifetimes of decades to millennia (lifetime as used here is the amount of...

Human Systems

Composition World Energy Consumption

Humans have had a profound impact on carbon cycling in the atmosphere, the terrestrial biosphere, and, to a lesser extent, the oceans. To understand how humans will continue to interact with these reservoirs in the future, one must understand the drivers responsible for how humans interact with the environment. Energy use has historically been viewed as an essential commodity for economic growth. The paradigm of grow or die historically meant increasing demands for additional resources and a...

The Vulnerability of the Carbon Cycle in the 21st Century An Assessment of Carbon ClimateHuman Interactions

Nicolas Gruber, Pierre Friedlingstein, Christopher B. Field, Riccardo Valentini, Martin Heimann, Jeffrey E. Richey, Patricia Romero Lankao, E.-Detlef Schulze, and Chen-Tung Arthur Chen In most scenario calculations to date, emissions from fossil-fuel burning are prescribed, and a carbon cycle model computes the time evolution of atmospheric CO2 as the residual between emissions and uptake by land and ocean, typically without considering feedbacks of climate on the carbon cycle (see, e.g.,...

Current Status and Past Trends of the Global Carbon Cycle

Christopher L.Sabine, Martin Heimann, Paulo Artaxo, Dorothee C. E. Bakker, Chen-Tung Arthur Chen, Christopher B. Field, Nicolas Gruber, Corinne Le Quere, Ronald G. Prinn, Jeffrey E. Richey, Patricia Romero Lankao,Jayant A. Sathaye, and Riccardo Valentini In a global, long-term perspective, the record of atmospheric CO2 content documents the magnitude and speed of climate-driven variations, such as the glacial-interglacial cycles (which drove CO2 variations of 100 parts per million ppm over...

R1l

Time series of anomalous non-fossil-fuel net land-atmosphere flux from the inversion (solid line, PgC y-1) compared with fire counts compiled by the European Space Agency (dashed line, arbitrary scale), both aggregated over two continental areas (R denbeck et al. 2003). Figure 8.4. Time series of anomalous non-fossil-fuel net land-atmosphere flux from the inversion (solid line, PgC y-1) compared with fire counts compiled by the European Space Agency (dashed line, arbitrary scale),...

Reservoir Connections

The background chapters in this volume discuss the various carbon reservoirs and the processes relevant to controlling atmospheric CO2 and related trace gas concentrations. To appreciate the Earth's carbon cycle and its evolution, it is necessary to exam ine the connections among the various carbon pools. This analysis must be done within a framework that provides an integrated perspective across both disciplinary and geographic boundaries, with particular emphasis on the carbon cycle as an...