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Background Human activities have changed the environment so profoundly over the past two centuries that human-induced climate change is now posing serious health-related threats to current and future generations. Rapid action from all scientific fields, including behavioral medicine, is needed to contribute to both mitigation of, and adaption to, climate change. Purpose This article aims to identify potential bi-directional associations between climate change impacts and health-related behaviors, as well as a set of key actions for the behavioral medicine community. Methods We synthesized the existing literature about (i) the impacts of rising temperatures, extreme weather events, air pollution, and rising sea level on individual behaviors (e.g. eating behaviors, physical activity, sleep, substance use, and preventive care) as well as the structural factors related to these behaviors (e.g. the food system); and (ii) the concurrent positive and negative roles that health-related behaviors can play in mitigation and adaptation to climate change. Results Based on this literature review, we propose a first conceptual model of climate change and health-related behavior feedback loops. Key actions are proposed, with particular consideration for health equity implications of future behavioral interventions. Actions to bridge the fields of behavioral medicine and climate sciences are also discussed. Conclusions We contend that climate change is among the most urgent issues facing all scientists and should become a central priority for the behavioral medicine community. [ABSTRACT FROM AUTHOR]

This editorial introduces the journal Climate Action to its audience and defines its aims and scope. It first calls for the need to understand climate action as the choices and behavior of international organizations, governments, civil society, businesses, and individuals. Next, it discusses both the facilitators and impacts of climate action. The editorial concludes with a research agenda for climate action to be studied from a transdisciplinary perspective with practitioners for triggering widespread societal transformation. [ABSTRACT FROM AUTHOR]

Following a previous 2014 review of perceived personal experience of climate change, the authors review relevant research published or reported between January 2014 and mid‐year 2019. The review findings suggest that the nature, significance, and influence of perceived personal experience of natural environment changes, conditions, and events deemed to be likely consequences of global climate change have been problematically conceptualized, researched, reported, and understood by many climate change scientists and by reporters of climate change science and their audiences. The nature, psychological significance, and psychological adaptation and issue engagement influence of personal experience of perceived environmental manifestations of climate change are arguably central considerations with respect to the human dimensions of climate change. These matters encompass public understanding of climate change science, both internal and external adaptation processes, and the psychological impacts of the ongoing stressor of climate change. They also affect issue engagement and behavioral change. It is increasingly necessary that existing issues with discipline‐based assumptive worlds, constructs and measures—and often unclear research and policy questions and objectives—be identified, clarified, and addressed. This particularly matters when researchers and policy makers are addressing public risk perceptions, understandings, and responses to global climate change, ideally to inform and enhance policies directed at climate change mitigation and adaptation, or, alternatively framed, directed towards public issue engagement and 'psychologically significant' as well as 'environmentally significant' behavioral change. This article is categorized under: Perceptions, Behavior, and Communication of Climate Change > Perceptions of Climate Change [ABSTRACT FROM AUTHOR]

Four associations filed l'affaire du siècle, a climate legal action against the French State before the Administrative Court of Paris in May 2019. This lawsuit questions the State's actions and inactions in matters of climate change mitigation and adaptation. Even though the complaint is mainly based on legal constructions and theories that are well-known to French Courts, this paper focuses on three ground-breaking legal innovations brought by the plaintiffs: a pre-existing general State obligation to combat climate change, a pre-existing right to live in a sustainable climate system, and, eventually, the remediation of the pure ecological damage (préjudice écologique) linked to climate change through a formal demand for monetary compensation of one symbolic euro and an injunctive relief to take all measures to limit global warming under the 1.5 °C threshold. [ABSTRACT FROM AUTHOR]

For aiming to keep global warming well-below 2 °C and pursue efforts to limit it to 1.5 °C, as set out in the Paris Agreement, a full-fledged assessment of negative emission technologies (NETs) that remove carbon dioxide from the atmosphere is crucial to inform science-based policy making. With the Paris Agreement in mind, we re-analyse available scenario evidence to understand the roles of NETs in 1.5 °C and 2 °C scenarios and, for the first time, link this to a systematic review of findings in the underlying literature. In line with previous research, we find that keeping warming below 1.5 °C requires a rapid large-scale deployment of NETs, while for 2 °C, we can still limit NET deployment substantially by ratcheting up near-term mitigation ambition. Most recent evidence stresses the importance of future socio-economic conditions in determining the flexibility of NET deployment and suggests opportunities for hedging technology risks by adopting portfolios of NETs. Importantly, our thematic review highlights that there is a much richer set of findings on NETs than commonly reflected upon both in scientific assessments and available reviews. In particular, beyond the common findings on NETs underpinned by dozens of studies around early scale-up, the changing shape of net emission pathways or greater flexibility in the timing of climate policies, there is a suite of "niche and emerging findings", e.g. around innovation needs and rapid technological change, termination of NETs at the end of the twenty-first century or the impacts of climate change on the effectiveness of NETs that have not been widely appreciated. Future research needs to explore the role of climate damages on NET uptake, better understand the geophysical constraints of NET deployment (e.g. water, geological storage, climate feedbacks), and provide a more systematic assessment of NET portfolios in the context of sustainable development goals. [ABSTRACT FROM AUTHOR]

This article reflects on the merits and shortfalls of bilateral research programmes aimed at strengthening climate change research capabilities, using the experience from two programmes, the PACC and IHCAP in Peru and India, respectively. The study highlights key aspects of these types of bilateral programmes, namely: capacity; performance, salary and appreciation; funding; bureaucracy and hierarchy; publishing; and data sharing. Furthermore, it emerged that these programmes would benefit from a more extensive consolidation phase of the research activities and partnership rather than rapidly transferring into out- and up-scaling phases. [ABSTRACT FROM AUTHOR]

The international literature on public attitudes finds that attitudes to climate change are closely related to attitudes to environmental protection. We ask whether this conclusion also holds for Norway. Our starting point is the political science literature on "old" versus "new" politics, old politics being defined in socio‐economic left or right terms and new politics being defined in accordance with an authoritarian or libertarian dimension in which environmental protection plays an important role. Based on these two axes, Herbert Kitschelt finds a new axis—a diagonal—combining old and new divides. According to Kitschelt, voters with traditional environmental attitudes have leftist and libertarian values, while voters favouring economic growth have rightist and authoritarian values. Using Norwegian data, we compare voters who favour traditional environmental protection and take climate change seriously with voters who only take climate change seriously. We expect that if climate change is perceived as one of many environmental threats, then the two voter groups are similar. We find that half of the voters see climate change as a big problem. Two thirds of these voters are in favour of environmental protection. However, the last third of these voters who take climate change seriously do not want greater environmental protection. Moreover, we find interesting differences between these groups. Those in the latter group have leftist and libertarian values, whereas climate‐only voters have rightist and authoritarian values. Thus the two groups of voters are dissimilar. Interestingly, this pattern corresponds to alignments along Kitschelt's new diagonal axis for party competition. [ABSTRACT FROM AUTHOR]

Evidence shows the global climate will continue to change over this century and beyond. A clear understanding of the climate change risk is suggested to be the foundation of the human adaptation. The plausible climate risk index reported by Germanwatch may be criticized as the fully compensatory assumption among underlying indicators, and the risk performance of each country in absolute terms cannot be assessed as the information on indicator level lost. We formulate an enhanced non-compensatory assessment scheme to reassess country's risk performance under climate change by means of penalizing underlying indicators that fail to satisfy certain criteria. Based on the new scheme, we can genuinely restrict the compensability among underlying indicators and provide informative decision aiding. A case study is performed to illustrate the effectiveness of our analysis by constructing a new climate risk index for 119 countries in terms of death toll, deaths per 100,000 inhabitants, absolute losses in PPP and losses per GDP unit. [ABSTRACT FROM AUTHOR]

The Advisory Opinion of the Inter-American (IA) Court of Human Rights on Environment and Human Rights , released in February 2018, has the potential to usher in a new era for the relationship between climate law and international human rights law. This article begins with the Inuit Petition submitted to the IA Commission on Human Rights in 2005 to identify three legal challenges which it brought to light on the application of the international human rights framework to climate change: enforceability, causality, and extraterritoriality. By relying on examples from the Human Rights Council and the Paris Agreement negotiations, we show that these three issues continue to have an impact on the relationship between climate law and human rights. We then draw attention to the groundbreaking character of the IA Court's Advisory Opinion, and in particular to the finding that the American Convention on Human Rights gives rise to an autonomous right to a healthy environment and to state duties that are both preventive and extraterritorial in nature. We suggest that the IA Court's revisiting of the three legal hurdles provides an opportunity to close the gap between the disciplines of international human rights and climate law. [ABSTRACT FROM AUTHOR]

Climate change has multifaceted aesthetic dimensions of legal significance. Global warming alters the aesthetic properties of nature, and further aesthetic changes are precipitated by climate mitigation and adaptation responses of impacted societies. The social and political struggles to influence climate change law are also influenced by aesthetics, as environmental activists and artists collaborate to influence public opinion, while conversely the business sector through its marketing and other aesthetic communications tries to persuade consumers of its climate-friendly practices to forestall serious action on global warming. This article distils and analyses these patterns in forging a novel account of the role of aesthetics in climate change law and policy, and it makes conclusions on how this field of law should consider aesthetic values through 'curatorial' guidance. [ABSTRACT FROM AUTHOR]

Purpose This study was conducted to analyse the extent at which Tanzanian newspapers paid attention to climate change information over the period of 10 years between January 2006 and December 2015.Design/methodology/approach Six Tanzanian newspapers were quantitatively content analysed for frequencies of coverage to climate change information.Findings The results indicate that of total six Tanzanian newspapers had very few (684; 0.84 per cent) articles on climate change which is an average of 68.4 articles per year. Much attention was given to entertainment (24,331; 30 per cent) followed by miscellaneous (19,413; 24.0 per cent) and advertisements (18,112; 22.3 per cent). The Pearson’s chi-square test indicates that there was a significant difference in χ2 = 21,765, p-value < 2.2e −16 between the level of coverage of climate change articles on other topics in the selected newspapers.Research limitations/implications Scanning the sampled six newspapers for climate change information and recording the results in the code sheet for the period of 10 years was a tedious and time-consuming exercise which demanded researchers and coders to be extremely careful. Also it is possible that the sampling strategy used led to missing some data that would have resulted into different conclusions about each newspaper’s coverage on climate change. However, the systematic sampling strategy was applied for a long period, that is, 40 months for each newspaper that increased the reliability and accuracy of the results and conclusions about the overall trends in each newspaper’s coverage of climate change information.Practical implications These findings imply that, as the disseminators of information, Tanzanian newspapers did not pay adequate attention to climate change issues. The study concludes that contrary to the fact that climate change is among the threatening phenomena in Tanzania that would commensurate a significant attention in the media, the findings of this study indicate that the volume of coverage devoted to climate change by the newspapers in Tanzania is very low and disproportionate to the level of threat. This leaves a question on the Tanzanian newspapers’ dedication to reporting climate change information. It is therefore recommended that newspapers’ media owners, editors and journalists should be environmental nationalistic enough to frequently report climate change information, and the scope of the government-owned newspapers should be revisited to ensure more coverage of climate change information in their publication which can be done by having a section specifically dedicated for climate change issue.Originality/value This study has therefore contributed to the growing body of analytical research knowledge on the role of newspapers in the dissemination of climate change information in Tanzania. This study has also highlighted the importance of taking into account newspapers coverage of climate change information which can further be used for policy recommendations to improve the climate change information communication system through the use of newspapers and show the credibility of the newspapers in creating awareness of climate change in Tanzania. [ABSTRACT FROM AUTHOR]

In an Editorial discussing the Special Issue on Climate Change and Health, guest editors Jonathan Patz and Madeleine Thompson summarize key issues in the field and describe the significance of research studies included in the issue. [ABSTRACT FROM AUTHOR]

This study examined the first- and third-person effects of emotional and informational messages, particularly relating to the critical issue areas of energy, the environment, and global warming. Due to intense political polarization on such issues, it also explored the role of political party identification. The results of an experiment indicated that informational messages about the environment produced third-person effects, while environmental advertisements meant to evoke emotion caused first-person effects. Moreover, emotional environmental advertisements appealed more to Republicans and those who did not support a political party. As such, indirect, emotional messages appear to represent an opportunity for strategic environmental communicators to design campaigns that resonate with potentially unreceptive audiences. [ABSTRACT FROM PUBLISHER]

Several studies have been using quantified consensus within climate science as an argument to foster climate policy. Recent efforts to communicate such scientific consensus attained a high public profile but it is doubtful if they can be regarded successful. We argue that repeated efforts to shore up the scientific consensus on minimalist claims such as “humans cause global warming” are distractions from more urgent matters of knowledge, values, policy framing and public engagement. Such efforts to force policy progress through communicating scientific consensus misunderstand the relationship between scientific knowledge, publics and policymakers. More important is to focus on genuinely controversial issues within climate policy debates where expertise might play a facilitating role. Mobilizing expertise in policy debates calls for judgment, context and attention to diversity, rather than deferring to formal quantifications of narrowly scientific claims. [ABSTRACT FROM PUBLISHER]

Although there is increasing public awareness of global warming, there is a gap between such perception and relevant actions to combat the problem. In order to develop effective strategies for facilitating public actions, in this paper we draw upon framing theory and a dual processing model. Based on an experiment involving 261 participants from a large public university in Taiwan, this study found that by framing global warming as a local issue, communication messages can trigger both analytic (issue relevance) and affective (negative emotions) appraisals, which, in turn, will increase people's intentions to take actions. This study provides important insights for government and environmental groups when designing communication campaigns on this issue. [ABSTRACT FROM PUBLISHER]

Misinformation can undermine a well-functioning democracy. For example, public misconceptions about climate change can lead to lowered acceptance of the reality of climate change and lowered support for mitigation policies. This study experimentally explored the impact of misinformation about climate change and tested several pre-emptive interventions designed to reduce the influence of misinformation. We found that false-balance media coverage (giving contrarian views equal voice with climate scientists) lowered perceived consensus overall, although the effect was greater among free-market supporters. Likewise, misinformation that confuses people about the level of scientific agreement regarding anthropogenic global warming (AGW) had a polarizing effect, with free-market supporters reducing their acceptance of AGW and those with low free-market support increasing their acceptance of AGW. However, we found that inoculating messages that (1) explain the flawed argumentation technique used in the misinformation or that (2) highlight the scientific consensus on climate change were effective in neutralizing those adverse effects of misinformation. We recommend that climate communication messages should take into account ways in which scientific content can be distorted, and include pre-emptive inoculation messages. [ABSTRACT FROM AUTHOR]

It is time to move past the concept of sustainability. The realities of the Anthropocene warrant this conclusion. They include unprecedented and irreversible rates of human-induced biodiversity loss, exponential increases in per-capita resource consumption, and global climate change. These factors combine to create an increasing likelihood of rapid, nonlinear, social and ecological regime changes. The recent failure of the Rio + 20 provides an opportunity to collectively reexamine—and ultimately move past—the concept of sustainability as an environmental goal. We must face the impossibility of defining—let alone pursuing—a goal of “sustainability” in a world characterized by such extreme complexity, radical uncertainty and lack of stationarity. After briefly examining sustainability's failure, we propose resilience thinking as one possible new orientation and point to the challenges associated with translating resilience theory into policy application. [ABSTRACT FROM AUTHOR]

This article addresses the uneven impacts of climate change on women. To date, there has been a significant emphasis on climate science and technological solutions to aid mitigation and adaptation strategies. This has led to a form of global managerialism that presupposes that all people can adapt with the right resources and knowledge. In this article, it is argued that the differential impacts of climate change on women demand that climate actions and strategies require gender sensitivity and that further research on climate change, adaptations, and actions includes a gendered analysis. WIREs Clim Change 2013, 4:351-358. doi: 10.1002/wcc.232 For further resources related to this article, please visit the WIREs website. [ABSTRACT FROM AUTHOR]

We present results from multiple comprehensive models used to simulate an aggressive mitigation scenario based on detailed results of an Integrated Assessment Model. The experiment employs ten global climate and Earth System models (GCMs and ESMs) and pioneers elements of the long-term experimental design for the forthcoming 5th Intergovernmental Panel on Climate Change assessment. Atmospheric carbon-dioxide concentrations pathways rather than carbon emissions are specified in all models, including five ESMs that contain interactive carbon cycles. Specified forcings also include minor greenhouse gas concentration pathways, ozone concentration, aerosols (via concentrations or precursor emissions) and land use change (in five models). The new aggressive mitigation scenario (E1), constructed using an integrated assessment model (IMAGE 2.4) with reduced fossil fuel use for energy production aimed at stabilizing global warming below 2 K, is studied alongside the medium-high non-mitigation scenario SRES A1B. Resulting twenty-first century global mean warming and precipitation changes for A1B are broadly consistent with previous studies. In E1 twenty-first century global warming remains below 2 K in most models, but global mean precipitation changes are higher than in A1B up to 2065 and consistently higher per degree of warming. The spread in global temperature and precipitation responses is partly attributable to inter-model variations in aerosol loading and representations of aerosol-related radiative forcing effects. Our study illustrates that the benefits of mitigation will not be realised in temperature terms until several decades after emissions reductions begin, and may vary considerably between regions. A subset of the models containing integrated carbon cycles agree that land and ocean sinks remove roughly half of present day anthropogenic carbon emissions from the atmosphere, and that anthropogenic carbon emissions must decrease by at least 50% by 2050 relative to 1990, with further large reductions needed beyond that to achieve the E1 concentrations pathway. Negative allowable anthropogenic carbon emissions at and beyond 2100 cannot be ruled out for the E1 scenario. There is self-consistency between the multi-model ensemble of allowable anthropogenic carbon emissions and the E1 scenario emissions from IMAGE 2.4. [ABSTRACT FROM AUTHOR]

Lynne Cherry Brandwein Lecture March 2010 National Science Teachers Association (NSTA) Conference, Philadelphia, PA. Young Voices on Climate Change: Inspired and Empowered Youth Tackle Climate Science and Find Climate Solutions. As a child, Lynne Cherry was profoundly connected to the natural world and a special place. She watched the destruction of her world. Now, through her Young Voices on Climate Change project, she is trying to give teachers and young people the tools to prevent planetary meltdown on a greater scale. Global climate change is upon us and the need for education and action is immediate. Outreach, visual storytelling, and scientific understanding are especially necessary in light of the recent polls that show that the public is becoming more confused and less concerned about climate change. Cherry's climate book, co-authored with photojournalist Gary Braasch, and her Young Voices on Climate Change films feature climate solutions. They're about win-win-save the environment, protect human health, reduce global warming gases, demonstrate youth making a difference with practical tools, motivate engagement in climate science, take pride in increased science literacy, reach young people through their hearts as well as their minds, and save money. Although young people can help their parents, peers and communities understand climate science, they can also show them that reducing CO is in their economic interest, and spur them to take action. School carbon reduction initiatives are spilling over into communities yielding measurable results in both global warming gas reductions and significant monetary savings. [ABSTRACT FROM AUTHOR]

Soil respiration, RS, the flux of microbially and plant-respired carbon dioxide (CO2) from the soil surface to the atmosphere, is the second-largest terrestrial carbon flux. However, the dynamics of RS are not well understood and the global flux remains poorly constrained. Ecosystem warming experiments, modelling analyses and fundamental biokinetics all suggest that RS should change with climate. This has been difficult to confirm observationally because of the high spatial variability of RS, inaccessibility of the soil medium and the inability of remote-sensing instruments to measure RS on large scales. Despite these constraints, it may be possible to discern climate-driven changes in regional or global RS values in the extant four-decade record of RS chamber measurements. Here we construct a database of worldwide RS observations matched with high-resolution historical climate data and find a previously unknown temporal trend in the RS record after accounting for mean annual climate, leaf area, nitrogen deposition and changes in CO2 measurement technique. We find that the air temperature anomaly (the deviation from the 1961–1990 mean) is significantly and positively correlated with changes in RS. We estimate that the global RS in 2008 (that is, the flux integrated over the Earth’s land surface over 2008) was 98 ± 12 Pg C and that it increased by 0.1 Pg C yr-1 between 1989 and 2008, implying a global RS response to air temperature (Q10) of 1.5. An increasing global RS value does not necessarily constitute a positive feedback to the atmosphere, as it could be driven by higher carbon inputs to soil rather than by mobilization of stored older carbon. The available data are, however, consistent with an acceleration of the terrestrial carbon cycle in response to global climate change. [ABSTRACT FROM AUTHOR]

Climate change mitigation poses significant challenges for South Africa and its energy development, historically highly energy intensive. At the same time, the country faces a host of daunting development challenges, exacerbated by the legacy of apartheid. Examining both challenges, this paper considers how alternative conceptions of a development path can be achieved. In the short term, energy efficiency provides large potential for mitigation - and energy savings at the same time. Changing South Africa's fuel mix, dependent to three-quarters on coal, is at least a medium-term challenge. The minerals-energy complex is so central to the economy that it is likely to take decades to change dramatically. The most transformative change is to an alteration in economic structure, likely to take long to achieve. The article examines specific policy instruments that might be implemented to achieve such a transformation. A transition to a low-carbon economy will require a paradigm shift in industrial policy. It will require considered provision for sectors sensitive to changes in energy prices. Building up new, climate-friendly industries will be needed to sustain employment and investment. To enable a just transition, provision will have to be made for emissions-intensive sectors, if they are to be phased out over time. South African government has adopted a vision, strategic direction and framework for climate policy. Policymakers have begun to understand that the future will be carbon constrained and that South Africa's emission will have to stop growing, stabilize and decline before mid-century. The challenge of climate change is a long-term challenge, requiring immediate action. This article examines actions at near-, medium- and long-term timescales. Its focus is on the most transformative change, that of seeking to shift development paths. [ABSTRACT FROM AUTHOR]

• Climate change is a threat for the sustainability of European small ruminants. • There are available adaptation measures to climate change. • Small ruminants are key species to keep livestock activity in harsh environments. • Small ruminants are key for upcycling underutilized feed resources. Projected climate change will involve an additional threat for the sustainability of small ruminant production systems in Europe. Aiming to understand its implications, we conducted a literature review on climate change interactions with sheep and goat systems. The review first identifies the main potential impacts on productivity at the animal level (heat stress effects) and at the forage level (quantity and quality). Results from analysed studies suggest that heat stress thresholds for small ruminants could be higher than previously indicated, although they still will be affected during projected heatwaves. At the forage level, the potential positive effect of CO 2 fertilisation will probably be counteracted in most of the cases due to extreme weather events and other limitations. Based on that findings, the review analyses the most suitable adaptation strategies on animal heat stress and pasture production. Particular attention is paid to integrated approaches, providing co-benefits at different levels. Finally, structural and practical challenges affecting small ruminants' sustainability in a climate change context are discussed, together with potential synergies and trade-offs among different policies and/or strategies. According to the information reviewed, small ruminant systems could be particularly vulnerable to environmental changes, as they are often produced in harsh areas under already severe circumstances. At the same time, they have particular features that could involve advantages against other livestock systems to cope with –and fight against- future climatic conditions. Consequently, they should play a important role for the climate change adaptation and mitigation options within the livestock sector. [ABSTRACT FROM AUTHOR]

• Climate worry raises personal responsibility and, thereby, diverse climate actions. • Individuals who strongly endorse biospheric values worry more about climate change. • Personal responsibility to reduce climate change relates to various climate actions. • Biospheric values primarily relate to personal climate mitigation behaviours. • Worry about climate change is primarily associated with climate policy support. The IPCC's report on Global Warming of 1.5°C positioned climate change as one of the most worrying issues mankind has ever faced. Although many people worry about climate change, there is still much unknown about the origins and outcomes of worry about climate change; particularly, whether and how it can motivate specific and personal climate actions. The current paper investigates this critical relationship with data from the European Social Survey Round 8 (44,387 respondents from 23 countries). As expected, the more individuals worried about climate change, the more likely they were to take and support climate action. Yet, the process through which this association occurred differed between actions. Specifically, worry was both directly and indirectly, via feelings of personal responsibility to reduce climate change, associated with climate policy support; whereas worry was mostly indirectly associated with personal climate mitigation behaviours, via personal responsibility. In addition, worry about climate change appears partly rooted in biospheric values (i.e., caring about nature and the environment), and biospheric values were also clearly, directly and positively related to personal climate mitigation behaviours. The relationships were highly consistent across countries but varied somewhat in size. The results show how generic feelings about climate change can directly and indirectly affect both climate policy support and personal climate mitigation behaviours, thereby providing critical insights for science and policy making. [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]