On the upper oceanic heat budget in the south china sea:Annual cycle

l.Intr0ducti0nInrecentyCarstheSouthChinaSea(SCS)hasbecomeoneofthemostimP0rtantregionsinthelocalair-seainteractionresearchbecauseofitssPecialgeographicPOsitionandsemi-encloseddeepbasincharacteristics.TheimP0rtanceoftheSCSisembodiedmainlyinwhichisoneofthekeyheatandmoisturesourcesofatmosphericcirculationineasternAsia.TheonsetandmaintenanceoftheSCSmonsoonarecloselyconnectedwiththelargeheattransportfromtheSCStoair(Yan,l997).Thestudyonspatial-temporalvariationofair-seaheatexchangeintheSCS…     

The global carbon budget: a conflicting claims problem

An effective climate agreement is urgently required, yet conflict between parties prevails over cooperation. Thanks to advances in science it is now possible to quantify the global carbon budget, the amount of available cumulative CO₂ emissions before crossing the 2 ^°C threshold (Meinshausen et al. Nature 458(7242):1158–1162, 2009). Countries carbon claims, however, exceed this. Historically such situations have been tackled with bankruptcy division rules. We argue that framing climate negotiations as a classical conflicting claims problem (O’Neill Math Soc Sci 2(4):345–371, 1982) may provide for an effective climate policy. We analyze the allocation of the global carbon budget among parties claiming the maximum emissions rights possible. Based on the selection of some desirable principles, we propose an efficient and sustainable allocation of the available carbon budget for the period 2000 to 2050 taking into account different risk scenarios.     

Fairness critically conditions the carbon budget allocation across countries

Countries’ nationally determined contributions to mitigate global warming translate to claims of country specific shares of the remaining carbon budget. The remaining global budget is limited by the aim of staying well below 2 °C, however. Here we show how fairness concerns quantitatively condition the allocation of this global carbon budget across countries. Minimal fairness requirements include securing basic needs, attributing historical responsibility for past emissions, accounting for benefits from past emissions, and not exceeding countries’ societally feasible emission reduction rate. The argument in favor of taking into account these fairness concerns reflects a critique of both simple equality- and sovereignty-principled reduction approaches, the former modelled here as the equal-per-capita distribution from now on, the latter as prolonging the inequality of the status-quo levels of emissions into the transformation period (considered a form of “grandfathering”). We find the option most in line with fairness concerns to be a four-fold qualified version of the equal-per-capita approach that incorporates a limited form of grandfathering.     

Carbon cycle–climate feedback sensitivity to parameter changes of a zero-dimensional terrestrial carbon cycle scheme in a climate model of intermediate complexity

Summary A series of sensitivity runs have been performed with a coupled climate–carbon cycle model. The climatic component consists of the climate model of intermediate complexity IAP RAS CM. The carbon cycle component is formulated as a simple zero-dimensional model. Its terrestrial part includes gross photosynthesis, and plant and soil respirations, depending on temperature via Q ₁₀-relationships (Lenton, 2000). Oceanic uptake of anthropogenic carbon is formulated is a bi-linear function of tendencies of atmospheric concentration of CO₂ and globally averaged annual mean sea surface temperature. The model is forced by the historical industrial and land use emissions of carbon dioxide for the second half of the 19th and the whole of the 20th centuries, and by the emission scenario SRES A2 for the 21st century. For the standard set of the governing parameters, the model realistically captures the main features of the Earth’s observed carbon cycle. A large number of simulations have been performed, perturbing the governing parameters of the terrestrial carbon cycle model. In addition, the climate part is perturbed, either by zeroing or artificially increasing the climate model sensitivity to the doubling of the atmospheric CO₂ concentration. Performing the above mentioned perturbations, it is possible to mimic most of the range found in the C4MIP simulations. In this way, a wide range of the climate–carbon cycle feedback strengths is obtained, differing even in the sign of the feedback. If the performed simulations are subjected to the constraints of a maximum allowed deviation of the simulated atmospheric CO₂ concentration (pCO_2(a)) from the observed values and correspondence between simulated and observed terrestrial uptakes, it is possible to narrow the corresponding uncertainty range. Among these constraints, considering pCO_2(a) and uptakes are both important. However, the terrestrial uptakes constrain the simulations more effectively than the oceanic ones. These constraints, while useful, are still unable to rule out both extremely strong positive and modest negative climate–carbon cycle feedback.     

A carbon budget for Brazil: Influence of future land-use change

Because of its large area of high C density forests and high deforestation rate, Brazil may play an important role in the global C cycle. The study reported here developed an estimate of Brazil's biotic CO₂-C budget for the period 1990–2010. The analysis used a spreadsheet C accounting model based on three major components: a conceptual model of ecosystem C cycling, a recently completed vegetation classification developed from remote-sensing data, and published estimates of C density for each of the vegetation classes. The dynamics of the model came from estimates of disturbance to ecosystems that release C and estimates of recovery from past disturbance that store C. The model was projected into the future with three alternative estimates of the rate of future land use change. Under all three deforestation scenarios Brazil was a C source in the range of about 3–5 × 10⁹ MgC over the 20-yr study period.The research described in this article has been funded wholly by the U.S. Environmental Protection Agency. This document has been prepared at the EPA National Health and Environmental Effects Research Laboratory in Corvallis, OR, U.S.A., through contract number 68-C8-0006 to ManTech Environmental Research Services, Corp. It has been subjected to the Agency's peer and administrative review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.     

Ocean-circulation model of the carbon cycle

A three-dimensional model of the natural carbon cycle in the oceans is described. The model is an extension of the inorganic ocean-circulation carbon cycle model of Maier-Reimer and Hasselmann (1987) to include the effect of the ocean biota. It is based on a dynamic, general circulation model of the world oceans. Chemical species important to the carbon cycle are advected by the current field of the general circulation model. Mixing occurs through numerical diffusivity (related to finite box size), a small explicit horizontal diffusivity, and a convective adjustment. An atmospheric box exchanges CO₂ with the surface ocean. There is no land biota provided in the present version of the model. The effect of the ocean biota on ocean chemistry is represented in a simple way and model distributions of chemical species are compared with distributions observed during the GEOSECS and other expeditions. Offprint requests to: R Bacastow     

Global carbon mechanisms: lessons and implications

We outline the theoretical and political background to the global carbon mechanisms and how they emerged in the form of the Kyoto Protocol??s Clean Development Mechanism, Joint Implementation, and Intergovernmental Emissions Trading. We present empirical data on the response to date and the variants that have arisen. Based on this, we analyse the issues and evidence on the main controversies around additionality, efficiency and effectiveness of the instruments. The final part of the paper considers some of the implications for future development.     

Achievability of the Paris Agreement targets in the EU: demand-side reduction potentials in a carbon budget perspective

Limiting global warming to ‘well below’ 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase even further to 1.5°C is an integral part of the 2015 Paris Agreement. To achieve these aims, cumulative global carbon emissions after 2016 should not exceed 940 – 390?Gt of CO₂ (for the 2°C target) and 167 – ?48?Gt of CO₂ (for the 1.5°C target) by the end of the century. This paper analyses the EU’s cumulative carbon emissions in different models and scenarios (global models, EU-focused models and national carbon mitigation scenarios). Due to the higher reductions in energy use and carbon intensity of the end-use sectors in the national scenarios, we identify an additional mitigation potential of 26–37 Gt cumulative CO₂ emissions up to 2050 compared to what is currently included in global or EU scenarios. These additional reductions could help to both reduce the need for carbon dioxide removals and bring cumulative emissions in global and EU scenarios in line with a fairness-based domestic EU budget for a 2°C target, while still remaining way above the budget for 1.5°C.

Key policy insights

• Models used for policy advice such as global integrated assessment models or EU models fail to consider certain mitigation potential available at the level of sectors.

• Global and EU models assume significant levels of CO₂ emission reductions from carbon capture and storage to reach the 1.5°C target but also to reach the 2°C target.

• Global and EU model scenarios are not compatible with a fair domestic EU share in the global carbon budget either for 2°C or for 1.5°C.

• Integrating additional sectoral mitigation potential from detailed national models can help bring down cumulative emissions in global and EU models to a level comparable to a fairness-based domestic EU share compatible with the 2°C target, but not the 1.5°C aspiration.

     

The budget of carbon dioxide variance in the surface layer over vegetated fields

The budget equation for carbon dioxide variance can be represented by production, dissipation and flux divergence terms. Each term is measured under near neutral to moderately unstable conditions over vegetated fields. The flux divergence term is about an order of magnitude smaller than production and dissipation terms, though it shows a loss for 0.006 < _v < 1 and a gain for 1 < - _v < 10. Here, _v is the Monin-Obukhov stability parameter including humidity effect. As expected from a closure of the budget, the nondimensional production and dissipation terms are basically identical and represented by the same functional form: (1–16 _v )^–1/2.