scholarly journals The relationship between net GHG emissions and radiative forcing with an application to Article 4.1 of the Paris Agreement

2021 ◽  
Vol 169 (1-2) ◽  
Author(s):  
Tom M. L. Wigley
Keyword(s):  
Global Warming ◽  
Radiative Forcing ◽  
Ghg Emissions ◽  
Zero Point ◽  
Paris Agreement ◽  
Scaling Method ◽  
Net Zero ◽  
Global Warming Potentials ◽  
The Relationship

AbstractThis paper provides an assessment of Article 4.1 of the Paris Agreement on climate; the main goal of which is to provide guidance on how “to achieve the long-term temperature goal set out in Article 2”. Paraphrasing, Article 4.1 says that, to achieve this end, we should decrease greenhouse gas (GHG) emissions so that net anthropogenic GHG emissions fall to zero in the second half of this century. To aggregate net GHG emissions, 100-year global warming potentials (GWP-100) are commonly used to convert non-CO2 emissions to equivalent CO2 emissions. The GWP-scaling method is tested using methane as an example. The temperature projections using GWP-100 scaling are shown to be seriously in error. This throws doubt on the use of GWP-100 scaling to estimate net GHG emissions. An alternative method to determine the net-zero point for GHG emissions based on radiative forcing is derived, where the net-zero point is identified with the maximum of GHG forcing. This shows that, to meet the Article 2 warming goal, the net-zero point for GHG emissions needs to be reached as early as 2036, much sooner than in the Article 4.1 window. Other scientific problems in Article 4.1 that further undermine its purpose to guide efforts to achieve the Article 2 temperature targets are discussed.

scholarly journals The relationship between net GHG emissions and radiative forcing with an application to Article 4.1 of the Paris Agreement.

2021 ◽  
Author(s):  
Tom M. L. Wigley
Keyword(s):  
Global Warming ◽  
Radiative Forcing ◽  
Ghg Emissions ◽  
Zero Point ◽  
Paris Agreement ◽  
Test Case ◽  
Net Zero ◽  
Global Warming Potentials ◽  
The Relationship

Abstract This paper provides an assessment of Article 4.1 of the Paris Agreement on climate; the main goal of which is to provide guidance on how “to achieve the long-term temperature goal set out in Article 2”. Paraphrasing, Article 4.1 says that, to achieve this end, we should decrease greenhouse gas (GHG) emissions so that net anthropogenic GHG emissions fall to zero in the second half of this century. To aggregate net GHG emissions, 100-year Global Warming Potentials (GWP-100) are commonly used to convert non-CO2 emissions to equivalent CO2 emissions. As a test case using methane, temperature projections using GWP-100 scaling are shown to be seriously in error. This throws doubt on the use of GWP-100 scaling to estimate net GHG emissions. An alternative method to determine the net-zero point for GHG emissions based on radiative forcing is derived. This shows that the net-zero point needs to be reached as early as 2036, much sooner than in the Article 4.1 window. Other scientific flaws in Article 4.1 that further undermine its purpose to guide efforts to achieve the Article 2 temperature targets are discussed.

Greenhouse gas metrics for net zero targets in science and policy

2021 ◽  
Author(s):  
Alexander Nauels ◽  
Carl-Friedrich Schleussner ◽  
Joeri Rogelj
Keyword(s):  
Global Warming ◽  
Radiative Forcing ◽  
National Level ◽  
National Policy ◽  
Paris Agreement ◽  
Climate Effect ◽  
Science And Policy ◽  
Net Zero ◽  
Global Warming Potentials ◽  
Metric Selection

<p>The treatment of non-CO<sub>2</sub> greenhouse gases is central for scientific assessments of effective climate change mitigation and climate policy. Radiative forcing of a unit of emitted short-lived gases decays quickly; on the order of a decade for methane, as opposed to centuries for CO<sub>2</sub>. Metric selection for comparing the climate effect of these emissions with CO<sub>2</sub> thereby comes with choices regarding short- vs. long-term priorities to achieve mitigation. The global nature of the well-mixed atmosphere also has implications for the transferability of concepts such as global warming potentials from the global to the national scale.</p><p>Here we present the implications of metric choice on global emissions balance and net zero, with a particular emphasis on the consistency with the wider context of the Paris Agreement, both on the global as well as the national level. Stylized scenarios show that interpreting the Paris Agreement emissions goals with metrics different from the IPCC AR5 can lead to inconsistencies with the Agreement’s temperature goal. Furthermore, we illustrate that introducing metrics that depend on historical emissions in a national context raises profound questions of equity and fairness, thereby questioning the applicability of non-constant global warming potentials at any but the global level. We provide suggestions to adequately approach these issues in the context of the Paris Agreement and national policy making.</p>

Towards high-quality net-zero targets

2021 ◽  
Author(s):  
Joeri Rogelj ◽  
Andy Reisinger ◽  
Annette Cowie ◽  
Oliver Geden
Keyword(s):  
Global Warming ◽  
Greenhouse Gas ◽  
Paris Agreement ◽  
Emissions Reduction ◽  
Special Report ◽  
High Quality ◽  
Net Zero ◽  
The World ◽  
Global Goal

<p>With the adoption of the Paris Agreement in 2015 the world has decided that warming should be kept well below 2°C while pursuing a limit of 1.5°C above preindustrial levels. The Paris Agreement also sets a net emissions reduction goal: in the second half of the century, the balance of global anthropogenic greenhouse gas emissions and removals should become net zero. Since 2018, in response to the publication of the IPCC Special Report on Global Warming of 1.5°C, a flurry of net zero target announcements has ensued. Many countries, cities, regions, companies, or other organisations have come forward with targets to reach net zero, or become carbon or climate neutral. These labels describe a wide variety of targets, and rarely detailed. Lack of transparency renders it impossible to understand their ultimate contribution towards the global goal. Here we present a set of key criteria that high-quality net zero targets should address. These nine criteria cover emissions, removals, timing, fairness and a long-term vision. Unless net zero targets provide clarity on these nine criteria, we may not know until it is too late whether the collective promise of net zero targets is adequate to meet the global goal of the Paris Agreement.</p>

scholarly journals Atmospheric Lifetimes, Infrared Absorption Spectra, Radiative Forcings and Global Warming Potentials of NF<sub>3</sub> and CFC-115

2016 ◽  
Author(s):  
Anna Totterdill ◽  
Tamás Kovács ◽  
Wuhu Feng ◽  
Sandip Dhomse ◽  
Christopher J. Smith ◽  
...  
Keyword(s):  
Global Warming ◽  
Cross Sections ◽  
Infrared Absorption ◽  
Radiative Forcing ◽  
Climate Model ◽  
Radiative Forcings ◽  
Atmospheric Window ◽  
Infrared Absorption Spectra ◽  
Global Warming Potentials ◽  
Good Agreement

Abstract. Fluorinated compounds such as NF3 and C2F5Cl (CFC-115) are characterised by very large global warming potentials (GWPs) which result from extremely long atmospheric lifetimes and strong infrared absorptions in the atmospheric window. In this study we have experimentally determined the infrared absorption cross-sections of NF3 and CFC-115, calculated the radiative forcing and efficiency using two radiative transfer models and identified the effect of clouds and stratospheric adjustment. The infrared cross sections are in good agreement with previous measurements, whereas the resulting radiative forcings and efficiencies are, on average, around 10 % larger. A whole atmosphere chemistry-climate model was used to determine the atmospheric lifetimes of NF3 and CFC-115 to be (616 ± 34) years and (492 ± 22) years, respectively. The GWPs for NF3 are estimated to be 14 600, 19 400 and 21 400 over 20, 100 and 500 years, respectively. Similarly, the GWPs for CFC-115 are 6120, 8060 and 8630 over 20, 100 and 500 years, respectively.

scholarly journals A new scenario logic for the Paris Agreement long-term temperature goal

2020 ◽  
Author(s):  
Joeri Rogelj ◽  
Daniel Huppmann ◽  
Volker Krey ◽  
Keywan Riahi ◽  
Leon Clarke ◽  
...  
Keyword(s):  
Global Warming ◽  
Integrated Assessment ◽  
Transition Period ◽  
Paris Agreement ◽  
Climate Change Scenarios ◽  
Industrial System ◽  
Carbon Neutrality ◽  
Climate Action ◽  
Near Term

&lt;p&gt;To understand how global warming can be kept well-below 2&amp;#176;C and even 1.5&amp;#176;C, climate policy uses scenarios that describe how society could transform in order to reduce its greenhouse gas emissions. Such scenario are typically created with integrated assessment models that include a representation of the economy, and the energy, land-use, and industrial system. However, current climate change scenarios have a key weakness in that they typically focus on reaching specific climate goals in 2100 only. &lt;br&gt;&lt;br&gt;This choice results in risky pathways that delay action and seemingly inevitably rely on large quantities of carbon-dioxide removal after mid-century. Here we propose a framework that more closely reflects the intentions of the UN Paris Agreement. It focusses on reaching a peak in global warming with either stabilisation or reversal thereafter. This approach provides a critical extension of the widely used Shared Socioecononomic Pathways (SSP) framework and reveals a more diverse picture: an inevitable transition period of aggressive near-term climate action to reach carbon neutrality can be followed by a variety of long-term states. It allows policymakers to explicitly consider near-term climate strategies in the context of intergenerational equity and long-term sustainability.&lt;/p&gt;

LNG use will be crucial to nations’ energy transitions

2021 ◽  
Keyword(s):  
Fossil Fuels ◽  
Fossil Fuel ◽  
Developing Economies ◽  
Ghg Emissions ◽  
Energy Transition ◽  
Market Volatility ◽  
Content Type ◽  
Market Growth ◽  
Net Zero

Significance LNG is cleaner than most fossil fuels but still incompatible with net zero emissions. India, China and other Asian economies see LNG imports as a ready and economically viable means of displacing coal and oil use. Natural gas and then LNG demand will eventually peak as the energy transition accelerates over the next 20 years. Impacts LNG market growth will embed fossil fuel use and infrastructure in developing economies’ energy mixes. Recent market volatility and record spot LNG prices may reverse the trend of greater reliance on spot transactions than long-term contracts. Although the greenhouse gas (GHG) benefits of LNG use in transport are far from clear, it will gain market share in the next few years. LNG project developers will seek to cut GHG emissions from their projects to prolong LNG's attractiveness in the energy transition.

On the evaluation of halocarbon radiative forcing and global warming potentials

1995 ◽  
Vol 100 (D1) ◽  
pp. 1271-1285 ◽  
Author(s):  
John S. Daniel ◽  
Susan Solomon ◽  
Daniel L. Albritton
Keyword(s):  
Global Warming ◽  
Radiative Forcing ◽  
Global Warming Potentials

scholarly journals Technical note: On comparing greenhouse gas emission metrics

2021 ◽  
Vol 21 (6) ◽  
pp. 4699-4708
Author(s):  
Ian Enting ◽  
Nathan Clisby
Keyword(s):  
Global Warming ◽  
Greenhouse Gas ◽  
Global Warming Potential ◽  
Radiative Forcing ◽  
Greenhouse Gas Emission ◽  
Technical Note ◽  
Short Term ◽  
Rates Of Change

Abstract. Many metrics for comparing greenhouse gas emissions can be expressed as an instantaneous global warming potential multiplied by the ratio of airborne fractions calculated in various ways. The forcing equivalent index (FEI) provides a specification for equal radiative forcing at all times at the expense of generally precluding point-by-point equivalence over time. The FEI can be expressed in terms of asymptotic airborne fractions for exponentially growing emissions. This provides a reference against which other metrics can be compared. Four other equivalence metrics are evaluated in terms of how closely they match the timescale dependence of FEI, with methane referenced to carbon dioxide used as an example. The 100-year global warming potential overestimates the long-term role of methane, while metrics based on rates of change overestimate the short-term contribution. A recently proposed metric based on differences between methane emissions 20 years apart provides a good compromise. Analysis of the timescale dependence of metrics expressed as Laplace transforms leads to an alternative metric that gives closer agreement with FEI at the expense of considering methane over longer time periods. The short-term behaviour, which is important when metrics are used for emissions trading, is illustrated with simple examples for the four metrics.

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