Search

Agriculture is a significant contributor to anthropogenic global warming. In recent years, agricultural greenhouse gas (GHG) emissions in China, which is the largest emitter, has been decreasing. In order to identify whether or not Chinese agricultural development has affected GHG emission, we used the logarithmic mean Divisia index (LMDI) factor decomposition model to study the effect of productivity factors on GHG emission and their characteristics in four phases of Chinese agricultural development. The results indicate that land productivity is the most significantly promotion factor which contributes 1.12 Gt CO2e GHG emission growth. On the contrary, technological input intensity exerts an obvious mitigating effect with 1.57 Gt CO2e GHG emission reduction. The effects of productivity factors on GHG emission differ between household-based farming systems and large-scale management systems. A more nuanced perspective on the significant role of agricultural large-scale management in GHG emission could aid climate change mitigation. [ABSTRACT FROM AUTHOR]

Copyright of Agricultural Outlook (1673-3908) is the property of Institute of Agricultural Information, Chinese Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper assesses the effectiveness of the environmental-related commitments contained in preferential trade agreements (PTAs) on climate change mitigation. A novel and detailed database identifying nearly 300 different types of environmental provisions from more than 680 PTAs since 1947 allows us to distinguish the PTAs with climate-related provisions (PTAwCP) from those with provisions related to other environmental issues. Using panel data covering 165 countries over the period 1995 to 2012, controlling for endogeneity issues, our main result shows that PTAwCP statistically reduce the emissions while the effect of PTAs with provisions related to other environmental issues remains negative but does not significantly affect GHG emissions. Our results suggest that it is rather the specific climate-related provisions in PTAwEP that reduce emissions (carbon dioxide, methane and nitrous oxide). Thus, to be effective in terms of mitigating climate change, PTAwEP should contain climate-related commitments. [ABSTRACT FROM AUTHOR]

Copyright of Gestión y Ambiente is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Reducing the emissions of greenhouse gases (GHGs) is vital for mitigating climate change and meeting commitments to international agreements such as the COP 21 Paris Agreement of 2015. Agriculture is reported to account for approximately 11 percent of total global GHG emissions such that: the agricultural sector has an important role to play in meeting climate change mitigation objectives. However, there is currently little consensus on how farm management and interventions, along with interactions with in-field variability, such as soil type, affect the production and assimilation of GHGs in arable crop lands. Practical recommendations for farmers are often vague or generalised, and models (e.g. on the amount of nitrogen fertiliser applied) are used despite limited understanding of the influence of local conditions, such as the importance of soil type. Here, we report the findings of a systematic map of the evidence relating to the impact on GHG flux from the in-field management of arable land in temperate regions. Methods: We searched for, collated and catalogued research relating to the effects of in-field arable farming practices in temperate systems on GHG emissions. Results from 6 bibliographic databases, a web-based search engine and organisational websites were combined with evidence from stakeholders. Duplicates were removed and the results were then screened for relevance at title and abstract, and full-text levels according to a predefined set of eligibility criteria (following consistency checking). Relevant studies were then coded and their meta-data extracted and used to populate a systematic map database describing each study's settings, methods and measured outcomes. Results: The mapping process identified 538 relevant studies from 351 articles. Nearly all of these (96%) were found from traditional research papers, with 42% from European countries and nearly half (203 studies) lasting for 12 months or less. Over half of all studies (55%) investigated multiple interventions with chemical fertiliser (n = 100), tillage (n = 70), and organic fertiliser (n = 30) the most frequently studied single intervention types. When combining individually studied and multiple interventions, the top three intervention types most frequently studied were: chemical fertiliser (n = 312); organic fertiliser (n = 176) and tillage (n = 158). Nitrous oxide was the most commonly studied outcome, with over double the number of studies compared to carbon dioxide, the next most studied outcome. Sandy loam and silty loam were the most commonly studied soils but there was a good distribution of studies across other types. However, studies predominately focused on humid sub-tropical (Cfa) and temperate oceanic (Cfb) climates, with hot summer Mediterranean (CSa) and warm summer Mediterranean (Csb) climate zones less represented. Conclusions: The mapping process identified clusters of research for chemical and organic fertiliser especially in relation to nitrous oxide emissions and for both carbon dioxide and nitrous dioxide in relation to tillage. Therefore, there is potential for further synthesis for these interventions. The spread of research across soil textures and in the humid sub-tropical and temperate oceanic climates may enable further synthesis to provide tailored in-field advice for farmers and provide an evidence base to inform subsidies policy. However, smaller amounts of research relating to biochar, cover crops, crop rotation, and nitrogen inhibitors highlight gaps where further research would be beneficial. [ABSTRACT FROM AUTHOR]

Climate change is ravaging the whole world, but the poor vulnerable developing countries are the hardest hit even though they are not primarily responsible for the massive greenhouse gases emissions causing global warming and climate change. This is tantamount to climate injustice as they are being impacted severely and have limited capacity to mitigate or adapt to the changing climate. Consequently, there is a need to share the burdens of climate change equally and equitably without discrimination. This paper submits that the developed industrialized rich countries are primarily responsible for climate change due to their massive emissions of greenhouse gases because of their industrial activities. Of note, most of the equipment and machineries used for production and other activities in these countries, utilized fossil fuel and emit greenhouse gases in the process. As such, justice demands that they have to be responsible for providing adaptation and mitigation measures to the developed countries through the mechanisms provided and set out in all international law instruments and agreements reached at the various Conferences of the Parties (COPs). A proportion of the monies and revenue received from the activities resulting in the emission of greenhouse gases are to be allocated to developing countries for adaptation and mitigation of climate change for them to be able to have clean environment, wellbeing, and sustainable livelihood. More importantly, it is imperative to transit to zero emissions globally this can be made possible using renewable energy as an alternative to fossil fuel. The international communities should therefore improve their strategies and effectiveness regarding the implementation of all the treaty agreements on zero-emission to attain climate justice for all. [ABSTRACT FROM AUTHOR]

The International Panel on Climate Change (IPCC) recommended more stringent climate mitigation strategies compared to the updated nationally determined contributions (NDC) presented by nations at COP27 to keep global warming temperatures below 2 °C. Given the unique geographical, political, and socioeconomic factors in different regions, it is imperative to evaluate diverse mitigation scenarios required to achieve global climate objectives. This study focuses on the Latin America and Caribbean region due to its vulnerability to global climate adversities and deteriorating climate conditions, notwithstanding its minor contribution to global emissions. Despite facing distinct climate changes, Latin America remains significantly understudied in the broader context of global climate research. The deployment of negative emission technology (NET) is crucial for achieving the end-of-century global climate goal of limiting global mean temperature to 1.5 °C and realizing regional net-zero greenhouse gas (GHG) emission targets. Most countries in Latin America have established such targets for 2050. Among various NETs, Direct Air Carbon Capture and Storage (DACCS) has recently gained research interests. This study examines the strategic implementation of NETs across the five socio-economic pathways (SSPs) to provide a comprehensive understanding of the uncertainties in regional mitigation actions and impacts on the intricate climate-energy-land-food-water nexus. In the scenario where emissions decrease by 56 % by 2030 compared to 2020 levels (NDC-56 %) on a net-zero trajectory, energy consumption under DACCS deployment is 13.1–36.2 % higher than without DACCS (between 2040 and 2100, across all SSPs). The energy demands of DACCS, especially in the aggressive NDC-56 % scenario place significant strain on energy resources, which is offset by fossil fuels. Under a globally co-ordinated climate policy and co-deployment of DACCS and Bioenergy with Carbon Capture and Storage (BECCS), the NDC-56 % scenario restricts global warming temperatures to 1.81–1.96 °C by 2100. • IAM analysis is used in assessing scenarios of net-zero goal of Latin America. • The deployment of DACCS under aggressive decarbonization is analysed. • The deployment of DACCS reduces the demand on BECCS requirements. • DACCS deployment will reach 88 MtCO 2 /year in the NDC-SSP1 scenario by 2100. [ABSTRACT FROM AUTHOR]

With the growing need for residential buildings as a result of population growth, the building sector is a high-priority area in climate change due to its large share of CO 2 emissions, the significant energy saving opportunities it represents, and the increasing expectations for occupant comfort. This paper presents the results of climate change impact assessment on a typical mid-rise residential building in four representative cities with different climatic characteristics in Turkey. Three different scenarios that characterize different solutions towards space cooling are developed, from naturally ventilated to fully air-conditioned. The energy requirements and corresponding CO 2 emissions due to space conditioning as well as occupant thermal comfort are the investigated building performance metrics. The preliminary results based on energy simulations indicate that pronounced overheating will be experienced in the future, which will have a strong effect on cooling energy use and/or occupant comfort. The projected energy demand also points to the future need to explore measures for climate change adaptation of buildings and the importance of the decarbonization of the electricity industry for climate change mitigation. The analysis results presented in this paper provide a basis for future studies on building retrofit for climate change. • Evaluation of climate change impact on a typical residential building in Turkey. • Cooling is to dominate thermal loads due to increased temperatures. • Warmer climates to be influenced most by negative effects. • Severe overheating for poorly ventilated, highly insulated buildings. • Adaptation measures needed for climate-proofing existing buildings. [ABSTRACT FROM AUTHOR]

Excessive emissions of greenhouse gases, such as carbon dioxide, can cause severe global climatic changes, which may include an increase in the global temperature, rise of the sea level, increase in wildfire, floods, and storms, in addition to changes in the amount of rain and snow. The global mitigation strategies that can be envisioned to reduce the release of greenhouse gas emissions to the atmosphere include retrofitting buildings with more energy-efficient systems, increasing the dependency on renewable energy sources in lieu of fossil fuels, increasing the use of sustainable transportation systems that rely on electricity and biofuels, and adopting globally more sustainable uses of land and forests. To reduce global climatic changes, the excess amount of carbon dioxide in the environment needs to be captured and stored in deep underground sedimentary reservoirs. The sedimentary reservoirs that contain water in the rock matrix provide a more secure CO2 sequestration medium. The injection of carbon dioxide causes a huge increase in the reservoir pore pressure and provokes the subsequent ground uplift. The excessive increase in pore pressure may also cause leakage of carbon dioxide into the potable water layers and to the atmosphere, thus leading to severe global climatic changes. In order to maintain the integrity of the sequestration process, it is crucial to inject a safe quantity of carbon dioxide into the sequestration site. Accordingly, the injection period and the safe values of injection parameters, like flow rate and injection pressure, need to be calculated a priori to ensure that the stored carbon dioxide will not leak into the atmosphere and jeopardize the climate mitigation strategy. To model carbon dioxide injection in reservoirs having a base fluid, such as water, one has to perform a two-phase flow modeling for both the injected and base fluids. In the present investigation, carbon dioxide is injected into Biyadh reservoir, wherein the two-phase flow through the reservoir structure is taken into account. This investigation aims to estimate the safe parameter values for carbon dioxide injection into the Biyadh reservoir, in order to avoid leakage of carbon dioxide through the caprock. In this context, the two cases of a fractured and non-fractured caprock are considered. To ensure a safe sequestration mechanism, the coupled reservoir stability analysis is performed to estimate the safe values of the injection parameters, thus furnishing data for a reliable global climate change mitigation strategy. The obtained results demonstrated that the injection of carbon dioxide has caused a maximum pore pressure increase of 25 MPa and a ground uplift of 35 mm. [ABSTRACT FROM AUTHOR]

To what extent Climate Change policies adopted by the United States (US) and China are a consequence of their respective domestic and international milieu, is this article's subject of inquiry. It compares the Climate Change policies of the US and China and argues that domestic and international socio-economic and political contexts together have helped shape the manner in which China and the US are dealing with climate change. Both powers collectively contribute about forty-five percent of global Green House Gas (GHG) emissions. Therefore, they are not only the main stakeholders in the Climate Change actions but also the 'responsibility bearers' to deal with 'Global Warming'. Both are nevertheless, failing to comply with the changing climate needs owing to the interplay of domestic and international factors that hamper the creation of efficient climate change policies by both states. Under the current policy environment, prospects for a reasonable GHG emission reduction seem unlikely for the two states. [ABSTRACT FROM AUTHOR]

As the world's climate changes, largely due to the spade of industrial "progress" and increase in human number, the emission of Green House gases into the atmosphere has grave implications on human health globally Within this context, 'third world' countries, including Nigeria are the worst hit by the immediate impact of climate change, even though they contribute least to the cause of the problem - emission of Green House gases, in comparison with their counterparts in the global North. Greenhouse gases (GHGs) have been proven to be responsible for global warming with the consequent threat to climate change. This paper contends that climate change is a major threat facing human health and existence in Nigeria and attempts a critical analysis of the roles of both developed and developing countries in contributing to the problem. It raises empathetic tone for the world's less privileges and future generation. The paper focuses on the impacts of climate change on Nigeria's economy, agriculture, health, security as well as environmental impacts. The paper submits that for the effects of climate change to be effectively resolve or managed in Nigeria and indeed globally, there should be, among other things, a sustained commitment on the part of the developed economies towards assisting developing countries in tackling the problem; attitudinal change and reorientation on the part of the populace towards environmental security, and green-friendly initiatives, adaptation to climate change requires public health strategies and improves surveillances. The paper ends with way forward on how causes of climate change can be adapted as well as mitigated. [ABSTRACT FROM AUTHOR]

Anthropogenic global climate change has large and mounting negative economic impacts. Companies and nations responsible for greenhouse gas (GHG) emissions are thus acquiring considerable potential liabilities. If litigation becomes widespread, renewable energy technologies (RETs) potentially offer emitters reduced liability for climate change. This benefit has been ignored because of the lack of knowledge of potential liabilities. To overcome this information deficit, this paper reviews recent literature on the potential for climate change litigation and methods to quantify liability for climate change. Next, the top 10 emitters in the U.S. are identified and their potential liability is quantified using standard GHG emission costs. Potential liabilities are explored in depth with a single case study company comparing the results of the fractional liability from only natural disasters within the U.S. for a single year to a sensitivity of the future costs of carbon emissions from other sources of emission-related liability. Then classes of potential climate change litigants are identified and their capacity to bring such lawsuits is evaluated. The results show that the net income available to shareholders of large companies could see a significant reduction from the emissions liability related to only natural disasters in the U.S. from a single coal-fired power plant. Finally, a rough estimate of the economic risk associated with future scenarios and existing organized international potential litigants is quantified. The results show that potential liability for climate change for the Alliance of Small Island States is over $570 trillion. It is concluded that as emitters begin to be held liable for damages resulting from GHG emissions resulting in climate change, a high value for liability mitigation would provide additional powerful incentives for deployment of renewable energy technologies. [ABSTRACT FROM AUTHOR]

Climate change and global warming are two huge current threats due to continuous anthropogenic emissions of greenhouse gases (GHGs) in the Earth's atmosphere. Accurate measurements and reliable quantifications of GHG emissions in air are thus of primary importance to the study of climate change and for taking mitigation actions. Therefore, the detection of GHGs should be the first step when trying to reduce their concentration in the environment. Throughout recent decades, nanostructured metal oxide semiconductors have been found to be reliable and accurate for the detection of many different toxic gases in air. Thus, the aim of this article is to present a comprehensive review of the development of various metal oxide semiconductors, as well as to discuss their strong and weak points for GHG detection. [ABSTRACT FROM AUTHOR]

In multi-gas climate policies such as the Kyoto Protocol one has to decide how to compare the emissions of different greenhouse gases. The choice of metric could have significant implications for mitigation priorities considered under the prospective negotiations for climate mitigation agreements. Several metrics have been proposed for this task with the Global Warming Potential (GWP) being the most common. However, these metrics have not been systematically compared to each other in the context of the 2 °C climate stabilization target. Based on a single unified modeling framework, we demonstrate that metric values span a wide range, depending on the metric structure and the treatment of the time dimension. Our finding confirms the basic salient point that metrics designed to represent different aspects of the climate and socio-economic system behave differently. Our result also reflects a complex interface between science and policy surrounding metrics. Thus, it is important to select or design a metric suitable for climate stabilization based on an interaction among practitioners, policymakers, and scientists. [ABSTRACT FROM AUTHOR]

A favoured method of assimilating information from state-of-the-art climate models into integrated assessment models of climate impacts is to use the transient climate response (TCR) of the climate models as an input, sometimes accompanied by a pattern matching approach to provide spatial information. More recent approaches to the problem use TCR with another independent piece of climate model output: the land-sea surface warming ratio ( φ). In this paper we show why the use of φ in addition to TCR has such utility. Multiple linear regressions of surface temperature change onto TCR and φ in 22 climate models from the CMIP3 multi-model database show that the inclusion of φ explains a much greater fraction of the inter-model variance than using TCR alone. The improvement is particularly pronounced in North America and Eurasia in the boreal summer season, and in the Amazon all year round. The use of φ as the second metric is beneficial for three reasons: firstly it is uncorrelated with TCR in state-of-the-art climate models and can therefore be considered as an independent metric; secondly, because of its projected time-invariance, the magnitude of φ is better constrained than TCR in the immediate future; thirdly, the use of two variables is much simpler than approaches such as pattern scaling from climate models. Finally we show how using the latest estimates of φ from climate models with a mean value of 1.6-as opposed to previously reported values of 1.4-can significantly increase the mean time-integrated discounted damage projections in a state-of-the-art integrated assessment model by about 15 %. When compared to damages calculated without the inclusion of the land-sea warming ratio, this figure rises to 65 %, equivalent to almost 200 trillion dollars over 200 years. [ABSTRACT FROM AUTHOR]

Abstract: Individual household and travel behaviors represent a sizeable contribution to U.S. greenhouse gas emissions. This paper investigates people''s knowledge of these behaviors and perceptions of these behaviors'' impact in causing and mitigating climate change. In the present study, a sample of college students were asked to list the behaviors they perform that cause global warming (GW) and the behaviors they could perform to mitigate GW, to rate the impact of the behaviors in terms of their effect on causing or mitigating GW, and to rate their intention to perform each of the behaviors. Results revealed that this sample was well aware of the effect of driving on GW. However, participants underestimated the relative impact of adjusting the thermostat and eating meat on GW and overestimated the impact of littering on causing GW. Although knowledge about GW-mitigating behaviors was not consistently related to behavioral intention, belief that a behavior mitigated GW (whether accurate or not) was strongly related to intention to perform that behavior. Specifically, correlations between belief in the mitigating potential of a behavior and intention were relatively high for adjusting the thermostat, reducing meat consumption, and several behaviors that do not mitigate GW, but were relatively low for reducing driving and not littering. Practical implications and comparisons with previous literature are discussed. [Copyright &y& Elsevier]

Numerous policy options exist to reduce future greenhouse gas emissions. A single-basket approach, which controls aggregate emissions, was adopted by the Kyoto Protocol. Such an approach allows emissions reductions of one gas to be traded with those of other gases in the 'basket', with the trade 'price' determined by some weighting metric like the Global Warming Potential. To reduce stratospheric ozone depletion, the Montreal Protocol also dealt with controlling many compounds, but did so employing an alternative, multi-basket scheme. Trading was allowed within each basket, but not among baskets. While the Montreal Protocol has been highly successful using this approach, we show that if a single-basket approach had been adopted the short-term success could have been at risk due to the non-unique relationship between controls and environmental impacts when using a single basket. Using climate policy as an example, and without considering technological and economic constraints, we further show that the magnitude of the ambiguities in impacts associated with a single-basket approach depends on the rapidity of the emission phaseout. Fast phaseouts lead to less ambiguity than do slow ones. These results suggest that for each set of greenhouse gas control policies considered, the benefit of additional flexibility associated with a single-basket approach should be weighed against the associated increased uncertainties in the impacts to ascertain whether a single- or a multi-basket approach has the greater chance of successfully mitigating climate change. [ABSTRACT FROM AUTHOR]

Climate change may impact agricultural greenhouse gas emissions (GHGs) and yields under higher temperatures, higher atmospheric CO2 concentrations, and variable precipitations. This calls for adaptation strategies to optimize agricultural productions with minimal GHGs. This study aimed to identify these optimum agricultural managements in response to current and projected climatic scenarios for the Choctawhatchee Basin in Southeastern USA, an experimentally unexplored data-scarce region lacking validation data. This scenario-based modeling study analyzed a total of 1344 scenarios consisting of four major crops, eight managements (varying tillage, manuring, and residue), and forty climatic combinations under current as wells as two representative concentration pathways with process-based Denitrification and Decomposition (DNDC) model. The results indicated that the region's GHGs and yields were most affected by higher temperatures (≥+3 °C) and extreme precipitation changes (≥±40%), while high atmospheric CO2 concentrations exerted positive fertilization effects. The manure-related and higher residue incorporation scenarios were found to be better options in varying climates with minimal present global warming potentials (GWP) of 0.23 k to −29.1 k MT equivalent CO2. As such, the study presented climate change impacts and potential mitigation options in the study region while presenting a framework to design GHG mitigation in similar data-scarce regions. [ABSTRACT FROM AUTHOR]

Humanity has come to depend on synthetic, factory made gases that have extremely significant global warming potential. Fluorinated greenhouse gases, or F-gases, such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6), and nitrogen trifluoride (NF3) have been termed "super pollutants" and "super greenhouse gases" given their severe and powerful impact on the climate. They are the most potent greenhouse gases known to modern science, with global warming potentials far greater than carbon dioxide, some up to almost 24,000 times more so. Troublingly, they are also the fastest growing class of greenhouse gas emissions around the world, especially in developing countries. Research suggest that almost 40% of their emissions by 2050 will fall outside the scope of international agreements such as the Paris Accord, Montreal Protocol and Kigali Amendment. Without comprehensive and sustained interventions, uncontrolled growth in F-gas emissions could offset all of the gains made by the Clean Development Mechanism of the Kyoto Protocol, or the cornerstone of existing international climate governance, the Nationally Determined Contributions of the 2015 Paris Accord. This review asks: What options are available to mitigate the environmental impacts of F-gases and thus make their manufacturing or disposal far more sustainable? What technical solutions and innovations exist to make their industrial usage low to zero carbon? What benefits will accrue from F-gas mitigation, and what barriers will need addressed? It undertakes a comprehensive and critical review of more than 140,000 sources of evidence, and a short list of 855 studies on the topic. It utilizes a sociotechnical lens that examines the manufacturing and use of F-gases across multiple sectors (including refrigeration, electronics manufacturing, non-ferrous metals processing, and applications in consumer goods) and components of its lifecycle (including not only manufacturing, but also use, disposal and destruction). We find that there are several policies and regulations that can be employed to address this already serious and growing climate change challenge. • Humanity depends on F-gases for many industrial and commercial applications. • F-gases are "super pollutants" given their severe and powerful impact on the climate. • Uncontrolled growth in F-gas emissions could offset the Kyoto Protocol and the Paris Accord. • New innovations and processes can greatly reduce F-gas manufacturing and use. • There are several policies and regulations that can be employed to further abate F-gas emissions. [ABSTRACT FROM AUTHOR]

In order to assess the merits of national climate change mitigation policies, it is important to have a reasonable benchmark for how much human-caused global warming would occur over the coming century with "Business-As-Usual" (BAU) conditions. However, currently, policymakers are limited to making assessments by comparing the Global Climate Model (GCM) projections of future climate change under various different "scenarios", none of which are explicitly defined as BAU. Moreover, all of these estimates are ab initio computer model projections, and policymakers do not currently have equivalent empirically derived estimates for comparison. Therefore, estimates of the total future human-caused global warming from the three main greenhouse gases of concern (CO2, CH4, and N2O) up to 2100 are here derived for BAU conditions. A semi-empirical approach is used that allows direct comparisons between GCM-based estimates and empirically derived estimates. If the climate sensitivity to greenhouse gases implies a Transient Climate Response (TCR) of ≥ 2.5 °C or an Equilibrium Climate Sensitivity (ECS) of ≥ 5.0 °C then the 2015 Paris Agreement's target of keeping human-caused global warming below 2.0 °C will have been broken by the middle of the century under BAU. However, for a TCR < 1.5 °C or ECS < 2.0 °C, the target would not be broken under BAU until the 22nd century or later. Therefore, the current Intergovernmental Panel on Climate Change (IPCC) "likely" range estimates for TCR of 1.0 to 2.5 °C and ECS of 1.5 to 4.5 °C have not yet established if human-caused global warming is a 21st century problem. [ABSTRACT FROM AUTHOR]