[Letter] Zero emission targets as long-term global goals for climate protection

Recently, assessments have robustly linked stabilization of global-mean temperature rise to the necessity of limiting the total amount of emitted carbon-dioxide (CO2). Halting global warming thus requires virtually zero annual CO2 emissions at some point. Policymakers have now incorporated this concept in the negotiating text for a new global climate agreement, but confusion remains about concepts like carbon neutrality, climate neutrality, full decarbonization, and net zero carbon or net zero greenhouse gas (GHG) emissions. Here we clarify these concepts, discuss their appropriateness to serve as a long-term global benchmark for achieving temperature targets, and provide a detailed quantification. We find that with current pledges and for a likely (>66%) chance of staying below 2 °C, the scenario literature suggests net zero CO2 emissions between 2060 and 2070, with net negative CO2 emissions thereafter. Because of residual non-CO2 emissions, net zero is always reached later for total GHG emissions than for CO2. Net zero emissions targets are a useful focal point for policy, linking a global temperature target and socio-economic pathways to a necessary long-term limit on cumulative CO2 emissions

Sinking to Zero: the role of carbon capture and negative emissions in EU climate policy. CEPS Policy Insight No. 2019-01 / January 2019

The updated EU long-term climate strategy with its net-zero emissions objective and the IPCC’s Special Report on the 1.5°C target prompt a renewed strategic look at negative emissions and carbon capture. Reaching net-zero greenhouse gas emissions requires more carbon sinks and other approaches to remove CO2 from the atmosphere. Furthermore, it will also require carbon capture technology to deal with residual emissions in energy-intensive industry that are otherwise difficult to avoid. Carbon capture and negative emissions are necessary, not just to compensate for any residual emissions, but also in their own right to reach the objectives set out in the Paris Agreement. Conventional mitigation should get precedence over compensation through negative emissions, owing to its high costs and resource demand. Trade-offs between mitigation and various negative emissions technologies should be acknowledged. Some approaches have only limited potential. Others require significant amounts of low-carbon energy and infrastructure

Net carbon emissions from deforestation in Bolivia during 1990-2000 and 2000-2010: results from a carbon bookkeeping model

Accurate estimates of global carbon emissions are critical for understanding global warming. This paper estimates net carbon emissions from land use change in Bolivia during the periods 1990-2000 and 2000-2010 using a model that takes into account deforestation, forest degradation, forest regrowth, gradual carbon decomposition and accumulation, as well as heterogeneity in both above ground and below ground carbon contents at the 10 by 10 km grid level. The approach permits detailed maps of net emissions by region and type of land cover. We estimate that net CO2 emissions from land use change in Bolivia increased from about 65 million tons per year during 1990-2000 to about 93 million tons per year during 2000-2010, while CO2 emissions per capita and per unit of GDP have remained fairly stable over the sample period. If we allow for estimated biomass to increase in mature forests, net CO2 emissions drop to close to zero. Finally, we find these results are robust to alternative methods of calculating emissions

Decarbonizing development: three steps to a zero-carbon future

This report lays out three steps for a smooth transition to a zero-carbon future and provides data, examples and policy advice to help countries makes the shift. Overview Getting to zero net emissions and stabilizing climate change starts with planning for the long-term future and not stopping at short-term goals. It means getting prices right as part of a broad policy package that can trigger changes in both investments and behaviors, and it requires smoothing the transition for those most affected. A new World Bank report walks policymakers through those three steps with data, examples and policy advice to help put countries on a path to decarbonizing their development in a smooth and orderly way. The solutions exist, and they are affordable – if governments take action today, the report says

Optimal Taxation Rule Reversal in the Presence of Gentle Polluters and Greedy Cleaners

The literature on the micro-economics of the eco-industry often assumed interiority of pollutant net emissions. In a perfectly competitive final good market vertically integrated with an upstream monopoly supply this assumption implies that an optimal tax is always greater than its associated marginal social damage. In this short note we will relax this assumption and challenge that result. The market structure generates a unique threshold on the scale of the marginal social damage, whereby for any value above the threshold an optimal tax is strictly lower and net emissions are zero

Going for zero: state decarbonisation strategies for prosperity in a zero-emission world

This paper explains why states should have a decarbonisation strategy and explores some key policy elements. Abstract Across the world, governments at all levels are implementing policies to reduce carbon emissions, address local air pollution, improve energy productivity, grow new industries and address energy security concerns. While these initiatives are as yet insufficient to avoid dangerous climate change or achieve the internationally agreed goal of avoiding 2°C warming above pre-industrial levels, the trend is clear. What is also clear is the ultimate destination or strategic objective that these policies need to have: the progressive phase-out of emissions to reach net zero levels, or ‘decarbonisation’. The OECD, World Bank and latest IPCC report have warned that avoiding irreversible and severe climate change impacts will require the global economy to be decarbonised before the end of the century. This requires energy systems, particularly electricity, to decarbonise well before then. Private sector actors are also moving forward. Leading multinational business groups and corporate leaders have called for action to achieve net zero global emissions by 2050. The financial sector is increasingly aware of the risks of ‘stranded assets’ resulting from both global decarbonisation efforts and the physical impacts of climate change. In Australia recent political and policy turmoil saw state governments retreat from many past climate policy initiatives. However some governments are now reconsidering their position and the risks posed to their economies and communities should they be left behind by this global trend toward decarbonisation. This paper explains why states should have a decarbonisation strategy and explores these key policy elements: Setting binding emission limits on major emitting facilities Incorporating carbon considerations into policy and planning processes Using procurement and management policies to help build markets for lower emission goods and services Continuing to develop and link energy efficiency policy frameworks Providing assistance: funding, technical, regulatory, trainin

U.S. BIOMASS SUPPLY FOR ELECTRICITY GENERATION: CLIMATE POLICY IMPLICATIONS AND CARBON NEUTRALITY

This paper investigates three important energy and climate policy issues: (1) the availability of biomass for electricity generation (i.e., supply), (2) climate policy effects on this supply, and (3) the net greenhouse gas reduction when biomass is used for electricity generation. Using a detailed model of U.S. agriculture and forestry markets and land-use, that includes a broad and diverse set of biomass feedstocks, we evaluate competing potential sub-national and feedstock specific supplies of biomass for U.S. electricity generation. Our preliminary results suggest significant supply, with residues dominating at lower delivered energy prices, and dedicated crops significant at higher prices. Sub-national variation is dramatic and will affect generation siting and sustainability. We find displacement of food crops, but net forest land and cropland expansion. We also find that GHG policies could substantially increase the delivered cost of biomass; however, the implications for individual regions and feedstocks is non-uniform, with some supplies falling to zero and others increasing. Finally, we find that bioelectricity is not carbon neutral, but can be emissions reducing relative to coal generation, yield greater direct GHG benefits than biofuels, and even result in domestic indirect emissions reductions with incentives for forest based feedstocks.Agricultural and Food Policy, Environmental Economics and Policy, Land Economics/Use, Resource /Energy Economics and Policy,

Implications of possible interpretations of 'greenhouse gas balance' in the Paris Agreement

The main goal of the Paris Agreement as stated in Article 2 is ‘holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C’. Article 4 points to this long-term goal and the need to achieve ‘balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases'. This statement on ‘greenhouse gas balance’ is subject to interpretation, and clarifications are needed to make it operational for national and international climate policies. We study possible interpretations from a scientific perspective and analyse their climatic implications. We clarify how the implications for individual gases depend on the metrics used to relate them. We show that the way in which balance is interpreted, achieved and maintained influences temperature outcomes. Achieving and maintaining net-zero CO2-equivalent emissions conventionally calculated using GWP100 (100-year global warming potential) and including substantial positive contributions from short-lived climate-forcing agents such as methane would result in a sustained decline in global temperature. A modified approach to the use of GWP100 (that equates constant emissions of short-lived climate forcers with zero sustained emission of CO2) results in global temperatures remaining approximately constant once net-zero CO2-equivalent emissions are achieved and maintained. Our paper provides policymakers with an overview of issues and choices that are important to determine which approach is most appropriate in the context of the Paris Agreement. This article is part of the theme issue ‘The Paris Agreement: understanding the physical and social challenges for a warming world of 1.5°C above pre-industrial levels'

Methane Mitigation:Methods to Reduce Emissions, on the Path to the Paris Agreement

The atmospheric methane burden is increasing rapidly, contrary to pathways compatible with the goals of the 2015 United Nations Framework Convention on Climate Change Paris Agreement. Urgent action is required to bring methane back to a pathway more in line with the Paris goals. Emission reduction from “tractable” (easier to mitigate) anthropogenic sources such as the fossil fuel industries and landfills is being much facilitated by technical advances in the past decade, which have radically improved our ability to locate, identify, quantify, and reduce emissions. Measures to reduce emissions from “intractable” (harder to mitigate) anthropogenic sources such as agriculture and biomass burning have received less attention and are also becoming more feasible, including removal from elevated-methane ambient air near to sources. The wider effort to use microbiological and dietary intervention to reduce emissions from cattle (and humans) is not addressed in detail in this essentially geophysical review. Though they cannot replace the need to reach “net-zero” emissions of CO2, significant reductions in the methane burden will ease the timescales needed to reach required CO2 reduction targets for any particular future temperature limit. There is no single magic bullet, but implementation of a wide array of mitigation and emission reduction strategies could substantially cut the global methane burden, at a cost that is relatively low compared to the parallel and necessary measures to reduce CO2, and thereby reduce the atmospheric methane burden back toward pathways consistent with the goals of the Paris Agreement