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Limiting warming to 1.5 °C is expected to lessen the risk of extreme events, relative to 2 °C. Considering Australia, this work shows a decrease of about 25% in the likelihood of record heat, both air and sea surface, if warming is limited to 1.5 °C. To avoid more severe impacts from climate change, there is international agreement to strive to limit warming to below 1.5 °C. However, there is a lack of literature assessing climate change at 1.5 °C and the potential benefits in terms of reduced frequency of extreme events1,2,3. Here, we demonstrate that existing model simulations provide a basis for rapid and rigorous analysis of the effects of different levels of warming on large-scale climate extremes, using Australia as a case study. We show that limiting warming to 1.5 °C, relative to 2 °C, would perceptibly reduce the frequency of extreme heat events in Australia. The Australian continent experiences a variety of high-impact climate extremes that result in loss of life, and economic and environmental damage. Events similar to the record-hot summer of 2012–2013 and warm seas associated with bleaching of the Great Barrier Reef in 2016 would be substantially less likely, by about 25% in both cases, if warming is kept to lower levels. The benefits of limiting warming on hydrometeorological extremes are less clear. This study provides a framework for analysing climate extremes at 1.5 °C global warming.

Whether a cloud is predominantly water or ice strongly influences interactions between clouds and radiation coming down from the Sun or up from the Earth. Being able to simulate cloud phase transitions accurately in climate models based on observational data sets is critical in order to improve confidence in climate projections, because this uncertainty contributes greatly to the overall uncertainty associated with cloud-climate feedbacks. Ultimately, it translates into uncertainties in Earth's sensitivity to higher CO2 levels. While a lot of effort has recently been made toward constraining cloud phase in climate models, more remains to be done to document the radiative properties of clouds according to their phase. Here we discuss the added value of a new satellite data set that advances the field by providing estimates of the cloud radiative effect as a function of cloud phase and the implications for climate projections.

Summary The election of a ‘post-truth' US president raises important issues for scientists. If rational arguments and proven facts cannot compete against demagoguery and scapegoating, how can we establish evidence-based policies to avert catastrophic climate change and other environmental disasters? Michael Gross reports.

Global climate change is a key challenge to the global economy in the twenty-first century. To address it properly, a combination of mitigation and adaptation strategies is required. Although the responsibility for adaptation lies primarily with national governments (though, even here, poorer countries need international support), mitigation is one of the key fields of international cooperation. There is little chance that the fundamental objective of stopping global temperatures from rising more than 2 °С can be reached without a stable and comprehensive global governance system. The current international climate change regime based on the Paris Agreement is insufficient to prevent catastrophic climate change. Deeper cooperation between leading economies is especially necessary, including among those that are now reluctant to reduce greenhouse gas emissions.

This paper addresses the call for more action-based narratives of grassroot resistance to runaway climate change. At a time when deep changes in society are needed in order to respond to climate change and related sustainability issues, there are calls for greater connectivity between science and society, and for more inclusive and disruptive forms of knowledge creation and engagement. The contention of this paper is that the forces and structures that create a disconnect between science and society must be ‘transgressed’. This paper introduces a concept of Transgressive Action Research as a methodological innovation that enables the co-creation of counter hegemonic pathways towards sustainability. Through the method of the Living Spiral Framework, fieldwork reflexions from the Colombian case study of the international T-Learning project were elicited, uncovering and explicating the transgressive learning qualities needed to respond to climate change. As part of a larger action–research project, this paper combines the arts with the social sciences, demonstrating how the concept of ‘Transgressive Action Research’ can enable co-researchers to engage in disruptive and transformative processes, meeting the need for more radical approaches to addressing the urgent challenges of climate change.

This study discusses the role that States should play to limit dangerous effects of climate change which leads to human rights violations as it’s a problem that crosses the borders and it’s already a reality that many countries and islands are threatened to disappear. The State bears the responsibility to protect human rights, a responsibility that lies on international organizations as well. In part one, we discuss the insufficient measures taken by States at the international level, as many factors constitute obstacles: (1) The lack of internationally recognized human right to the environment linked to the absence of a legal status for climate refugees make the responsibility approach untenable. (2) The difficulty to establish legal responsibility based on a causal contribution to harm makes the responsibility approach insupportable. In fact, the 2001 International Law Commission draft articles on state responsibility for internationally wrongful acts are not binding. But the great difficulty concerns the distribution of the repair burden between States responsible for the emission of greenhouse gases. It is extremely difficult, if not impossible, to measure the share of each State in climate change. (3) The limits of United Nations Frame Convention on Climate Change of which the great bargain is to avert catastrophic climate change consequences by reducing the average global temperature increase to about 2* above pre-industrial levels. Part two, suggests solutions through an advisory opinion from the International Court of Justice, and analyzes the successful regulation of climate change effects by domestic courts, by focusing on the Urgenda case in Netherlands.

This article discusses the phenomenon and mechanisms of climate change and the models used to study climate dynamics and predict future climate change. It describes past climate variations on the geological timescales reconstructed using paleoclimatological methods and a more recent climate change derived from observations. The article presents the scientific basis and the spectrum of existing climate models. An overview of modeling predictions of future climate change is given and principal uncertainties associated with climate predictions are discussed. A possible impact of future climate change on natural ecosystems, food production, and human health is also discussed.

The Global Deal for Nature sets an ambitious agenda to protect our biosphere through ecosystem conservation and land restoration., The Global Deal for Nature (GDN) is a time-bound, science-driven plan to save the diversity and abundance of life on Earth. Pairing the GDN and the Paris Climate Agreement would avoid catastrophic climate change, conserve species, and secure essential ecosystem services. New findings give urgency to this union: Less than half of the terrestrial realm is intact, yet conserving all native ecosystems—coupled with energy transition measures—will be required to remain below a 1.5°C rise in average global temperature. The GDN targets 30% of Earth to be formally protected and an additional 20% designated as climate stabilization areas, by 2030, to stay below 1.5°C. We highlight the 67% of terrestrial ecoregions that can meet 30% protection, thereby reducing extinction threats and carbon emissions from natural reservoirs. Freshwater and marine targets included here extend the GDN to all realms and provide a pathway to ensuring a more livable biosphere.

The Anthropocene poses profound challenges to the conservation of the Amazon rainforest, a global carbon reservoir. The forest’s unsustainable model of development, based on severe land use changes, and the effects of anthropogenic climate change may result in irreversible damage. In addition, crossing tipping points for the survival of the Amazon rainforest may trigger catastrophic climate change (CCC), which reflects the urgent need for a new development paradigm for the region. However, the prospects of the dieback of the Amazon as well as of a CCC scenario are generally overlooked in the academic and political debates. This chapter aims to fill this gap by exploring the link between irreversible environmental changes in the forest and potential CCC and by analyzing the challenge of sustainable development in the Brazilian Amazon, demonstrating how close a climate catastrophe might be; it then presents a novel development paradigm for the region. The revolutionary technologies of the Fourth Industrial Revolution are proposed as central to this necessary paradigm shift. Because the Amazon rainforest is a global natural asset for avoiding CCC, Brazil is also advised to follow a diplomatic plan that upholds fundamental ecological principles for creating a safe space for humanity, thus attracting international investments to manage and preserve the forest.

This paper aims to consider the meaning of the dismal theorem, as presented by Martin Weitzman [(2009) On modeling and interpreting the economics of catastrophic climate change. Review of Economics and Statistics91, 1–19]. The theorem states that a standard cost–benefit analysis breaks down if there is a possibility of catastrophes occurring. This result has a significant influence on debates regarding the economics of climate change. In this study, we present an intuitive similarity between the dismal theorem and the St. Petersburg paradox using a simple discrete probability distribution.

PrefaceAbbreviations1. Climate in Context2. The Character of the Atmosphere3. The World Ocean4. The Carbon Cycle and How It Influences Climate5. A Scientific Framework for Thinking About Climate Change6. Learning from Climates Past7. A Century of Warming and Some Consequences8. More Consequences: The Sensitive Arctic and Sea-Level Rise9. Climate Models and the Future10. Energy and the FutureNotesGlossaryBibliographyIndex

The biogeophysical effect of forests in a climate with permanent high-latitude ice cover has already been investigated. We extend this analysis to warm, basically ice-free climates, and we choose the early Eocene, some 54 to 52 million years ago, as paradigm for such type of climate. We use the Max Planck Institute for Meteorology Earth System Model to evaluate the radiative forcing of forests and the feedbacks triggered by forests in early Eocene and pre-industrial climate, respectively. To isolate first-order effects, we compare idealised simulations in which all continents are covered either by dense forests or by deserts with either bright or dark soil. In comparison with desert continents covered by bright soil, forested continents warm the planet in the early Eocene climate and in the pre-industrial climate. The warming can be attributed to different feedback processes, though. The lapse-rate – water-vapour feedback is stronger in early Eocene climate than in pre-industrial climate, but strong and negative cloud-related feedbacks nearly outweigh the positive lapse-rate – water-vapour feedback in the early Eocene climate. Subsequently, global mean warming by forests is weaker in the early Eocene climate than in the pre-industrial climate. Sea-ice related feedbacks are weak in the almost ice-free climate of the early Eocene, thereby leading to a weaker high-latitude warming by forests than in the pre-industrial climate. When the land is covered with dark soils, forests cool the early Eocene climate stronger than the pre-industrial climate because the lapse-rate and water-vapour feedbacks are stronger in the early Eocene climate. Cloud-related feedbacks are equally strong in both climates. We conclude that radiative forcing by forests varies little with the climate state, while most subsequent feedbacks depend on the climate state.

Many have claimed that climate change is an imminent threat to humanity, but there is no way to verify such claims. This is concerning, especially given the prominence of some of these claims and the fact that they are confused with other well verified and settled aspects of climate science. This paper seeks to build an analytical framework to help explore climate change’s contribution to Global Catastrophic Risk (GCR), including the role of its indirect and systemic impacts. In doing so it evaluates the current state of knowledge about catastrophic climate change and integrates this with a suite of conceptual and evaluative tools that have recently been developed by scholars of GCR and Existential Risk. These tools connect GCR to planetary boundaries, classify its key features, and place it in a global policy context. While the goal of this paper is limited to producing a framework for assessment; we argue that applying this framework can yield new insights into how climate change could cause global catastrophes and how to manage this risk. We illustrate this by using our framework to describe the novel concept of possible’ global systems death spirals,’ involving reinforcing feedback between collapsing sociotechnological and ecological systems.

Global climate change caused by human activities has posed a huge threat to the environmental governance and sustainability of human-being. Fortunately, the carbon emission trading scheme, a powerful tool for reducing carbon emissions, has been established in many countries to slow catastrophic climate change thus promoting human well-being. The nexuses between energy and European carbon markets have been extensively studied due to the grim reality of global climate change. However, no literature to date has examined the multi-scale associations between China’s energy and regional CET markets. This paper aims to fill this gap by utilizing a proposed wavelet-based multi-scale investigation framework to explore the information spillovers and dynamic dependence over different time horizons. The original energy and carbon return series are decomposed by the MODWT method. The TVP-VAR-based connectedness and the DECO-FIGARCH model are then built at each selected wavelet component. The wavelet coherence method is also applied to depict the time-frequency dependence. The empirical results demonstrate that the information spillovers at multivariate time-scales are heterogeneous. Generally, GDEA and the crude oil markets act as the information spillover net-transmitters at the raw data level and all wavelet scales. The dynamic spillovers present significant time-varying features and a similar evaluation trajectory. Besides, we offer strong evidence of a low dynamic equicorrelation between China’s energy and regional CET markets, suggesting the portfolio diversification benefits. Furthermore, the information spillover and dependence are proved to be more significant at longer time horizons. Finally, the energy-carbon portfolios offer diversification opportunities, and the risk reduction effectiveness varies with wavelet scales. Moreover, the optimal-weighted portfolio exhibits the best risk management performance.

Future global warming from anthropogenic greenhouse gas emissions will depend on climate feedbacks, the effect of which is expressed by climate sensitivity, the warming for a doubling of atmospheric CO2 content. It is not clear how feedbacks, sensitivity, and temperature will evolve in our warming world, but past warming events may provide insight. Here we employ paleoreconstructions and new climate-carbon model simulations in a novel framework to explore a wide scenario range for the Paleocene-Eocene Thermal Maximum (PETM) carbon release and global warming event 55.8Ma ago, a possible future warming analogue. We obtain constrained estimates of CO2 and climate sensitivity before and during the PETM and of the PETM carbon input amount and nature. Sensitivity increased from 3.3-5.6 to 3.7-6.5K (Kelvin) into the PETM. When taken together with Last Glacial Maximum and modern estimates, this result indicates climate sensitivity increase with global warming.

We study how heterogeneous beliefs about the causes and extent of global warming affect local mitigation and adaptation strategies and therefore global climate dynamics. Local policies are determined by expectations of policy makers about future climate. There are three types of expectations: strong skeptic, weak skeptic and ‘science-based’. Strong skeptics deny human-induced climate change and a possibility of a climate catastrophe. Weak skeptics believe that industrial emissions cause global warming, but deny catastrophic climate change. Science-based policy makers, considering the warning of the scientific community, account for both: human influence on climate and possible catastrophic shifts. Aggregate behavior of policy makers determines the total emission level which influences global climate dynamics. The paper argues that even if there are only skeptical policy makers the climate catastrophe can still be avoided.

Changes to the large-scale oceanic circulation are thought to slow the pace of transient climate change due, in part, to their influence on radiative feedbacks. Here we evaluate the interactions between CO2-forced perturbations to the large-scale ocean circulation and the radiative cloud feedback in a climate model. Both the change of the ocean circulation and the radiative cloud feedback strongly influence the magnitude and spatial pattern of surface and ocean warming. Changes in the ocean circulation reduce the amount of transient global warming caused by the radiative cloud feedback by helping to maintain low cloud coverage in the face of global warming. The radiative cloud feedback is key in affecting atmospheric meridional heat transport changes and is the dominant radiative feedback mechanism that responds to ocean circulation change. Uncertainty in the simulated ocean circulation changes due to CO2 forcing may contribute a large share of the spread in the radiative cloud feedback among climate models.

Solar geoengineering has been proposed as a potential means to counteract anthropogenic climate change, yet it is unknown how such climate intervention might affect the Earth's climate on the millennial time scale. Here we use the HadCM3L model to conduct a 1000year sunshade geoengineering simulation in which solar irradiance is uniformly reduced by 4% to approximately offset global mean warming from an abrupt quadrupling of atmospheric CO2. During the 1000year period, modeled global climate, including temperature, hydrological cycle, and ocean circulation of the high-CO2 simulation departs substantially from that of the control preindustrial simulation, whereas the climate of the geoengineering simulation remains much closer to that of the preindustrial state with little drift. The results of our study do not support the hypothesis that nonlinearities in the climate system would cause substantial drift in the climate system if solar geoengineering was to be deployed on the timescale of a millennium.

Global mean surface air temperature has risen since pre-industrial times and is expected to increase further in the future due to anthropogenic emissions of greenhouse gases. Global warming and associated changes in climate and environment at global and regional scales have been received increasing attention in recent decades. The extent of global mean temperature increase in the 21st century is of great scientific and socio-economic interest. A central issue for scientific research is the value of equilibrium climate sensitivity—the equilibrium change in global mean 2-m air temperature that would result from a sustained doubling of the atmospheric carbon dioxide concentration. Following the discussion of equilibrium climate sensitivity published in the anniversary issue of Science in 2005, here we interpret this indicator with new insights from the scientific literature. In brief, the equilibrium climate sensitivity was suggested as being 1.5–4.5°C, on the basis of the earliest generation of atmosphere-slab ocean general circulation models in the late 1970s. These values were confirmed by a hierarchy of climate models ranging from atmosphere-slab ocean to atmosphere–ocean general circulation models in the 1990s and the early 2000s and were used in the Intergovernmental Panel on Climate Change (IPCC) First to Third Assessment Reports. That range was reduced to 2.0–4.5°C by the IPCC Fourth Assessment Report in 2007, but was estimated at 1.5–4.5°C again by state of the art climate and Earth system models in the IPCC Fifth Assessment Report in 2013. Much effort is needed to improve our understanding of clouds and aerosols—the biggest sources of uncertainty—in the real world and then in climate and Earth system models. Due to limitations concerning instrument records prior to the last century, attention should also be given to changes in climate during the distant past, either through the use of reconstructions or simulations, in order to reduce uncertainties in equilibrium climate sensitivity.

The major states, in which Earth's climate operates, i.e., icehouse, greenhouse and hothouse, are epochs of tens of millions of years. These states set long-term boundary conditions that need to be considered for climate and sea-level interpretations. This paper summarizes the conceptual models for hydrological cycling derived from the characteristics of these three climate states. While glacio-eustatic forcing of sea-level changes under icehouse climate conditions is fairly well understood, the drivers of eustatic sea-level fluctuations under greenhouse conditions remain enigmatic. This lack of understanding may be related to incoherencies in the current ideas about the impact of accelerated hydrological cycling on sea level under greenhouse climate conditions. As an example for a greenhouse climate, we review evidences that link proxies for climate and sea level for the intensely studied, but controversially discussed, mid-Cretaceous sea-level history. Based on sequence stratigraphy and a recently published high-precision timescale, we demonstrate that the late Middle Turonian Pewsey δ13C isotope maximum represents a major transgression, not a regression as previously stated, which conflicts with the interpretation of a co-occurring δ18O maximum to reflect a short glacial episode. This contradiction can be solved by the concept, presented here, that dominance of aquifer-eustasy characterized sea-level forcing during the Turonian greenhouse climate, despite a possible, though contentious, sporadic presence of minor ice sheets. The effects of temperature and ice volume both lead to a pronounced δ18Ocarb maximum during glacio-eustatic regressions. In contrast, the opposing effects of temperature and groundwater volume on oxygen-isotope fractionation lead to a δ18Ocarb maximum during aquifer-eustatic transgressions. We suggest that, throughout Earth history, both aquifer-eustatic and glacio-eustatic forcing formed a combined sea-level response, with dominance of aquifer-eustasy being typical for the greenhouse climate mode. During the icehouse mode, aquifer-eustasy apparently remains active as a background process, but is outpaced by the glacio-eustatic effect.

This study investigates the alteration of climate feedbacks due to overestimated wintertime low-level cloud amount bias over the Arctic region (60°N–90°N) in a climate model. The climate feedback was quantitatively examined through radiative kernels that are pre-calculated radiative responses of climate variables to doubling of carbon dioxide concentration in NCAR Community Atmosphere Model version 3 (CAM3). Climate models have various annual cycle of the Arctic cloud amount at the low-level particularly with large uncertainty in winter and CAM3 may tend to overestimate the Arctic low-level cloud. In this study, the seasonal variation of low-level cloud amount was modified by reducing the wintertime cloud amount by up to 35 %, and then compared with the original without seasonal variation. Thus, we investigate how that bias may affect climate feedbacks and the projections of future Arctic warming. The results show that the decrease in low-level cloud amount slightly affected the radiation budgets because of a small amount of incident solar insolation in winter, but considerably changed water vapor and temperature profiles. Consequently, the most distinctive was decreases in water vapor feedback and contribution of heat transport (by −0.20 and −0.55 W m−2 K−1, respectively) and increases in the lapse rate feedback and cloud feedback (by 0.13 and 0.58 W m−2 K−1, respectively) during winter in this model experiment. This study suggests that the change in Arctic cloud amount effectively reforms the contributions of individual climate feedbacks to Arctic climate system and leads to opposing effects on different feedbacks, which cancel out in the model.

Climate sensitivity is an important index that measures the relationship between the increase in greenhouse gases and the magnitude of global warming. Uncertainties in climate change projection and climate modeling are mostly related to the climate sensitivity. The climate sensitivities of coupled climate models determine the magnitudes of the projected global warming. In this paper, the authors thoroughly review the literature on climate sensitivity, and discuss issues related to climate feedback processes and the methods used in estimating the equilibrium climate sensitivity and transient climate response (TCR), including the TCR to cumulative CO2 emissions. After presenting a summary of the sources that affect the uncertainty of climate sensitivity, the impact of climate sensitivity on climate change projection is discussed by addressing the uncertainties in 2°C warming. Challenges that call for further investigation in the research community, in particular the Chinese community, are discussed.

Closure of the Earth’s energy budget relies on strong aerosol cooling since 1998, if the same feedbacks apply for anthropogenic and natural variability. An analysis of climate model simulations suggests that these feedbacks are instead distinct.

Two decades of international negotiations show that agreeing on emission levels for climate change mitigation is a hard challenge. However, if early warning signals were to show an upcoming tipping point with catastrophic damage, theory and experiments suggest this could simplify collective action to reduce greenhouse gas emissions. At the actual threshold, no country would have a free-ride incentive to increase emissions over the tipping point, but it remains for countries to negotiate their emission levels to reach these agreements. We model agents bargaining for emission levels using strategic reasoning to predict emission bids by others and ask how this affects the possibility of reaching agreements that avoid catastrophic damage. It is known that policy elites often use a higher degree of strategic reasoning, and in our model this increases the risk for climate catastrophe. Moreover, some forms of higher strategic reasoning make agreements to reduce greenhouse gases unstable. We use empirically informed levels of strategic reasoning when simulating the model.

We use both prescribed sea surface temperature and fully coupled versions of the Geophysical Fluid Dynamics Laboratory coupled climate model (CM3) to analyze the sensitivity of radiative forcing, ocean heat uptake, and climate feedback to changes in anthropogenic greenhouse gases and aerosols considered separately over the 1870 to 2005 period. The global anthropogenic aerosol climate feedback parameter (− α) of −1.13 ± 0.33 Wm−2 K−1 is indistinguishable from the greenhouse gas − α of −1.28 ± 0.23 Wm−2 K−1. However, this greenhouse gas climate feedback parameter is about 50% larger than that obtained for CM3 from a widely used linear extrapolation method of regressing Earth's top of atmosphere imbalance against surface air temperature change in idealized CO2 radiative forcing experiments. This implies that the global mean surface temperature change due to forcing over the 1870–2005 period is 50% smaller than that predicted using the climate feedback parameter obtained from idealized experiments. This difference results from time dependence in α, which makes the radiative forcing obtained by the fixed sea surface temperature method incompatible with that obtained by the linear extrapolation method fitted over the first 150 years after CO2 is quadrupled. On a regional scale, α varies greatly between the greenhouse gas and aerosol case. This suggests that the relationship between transient and equilibrium climate sensitivities obtained from idealized CO2 simulations, using techniques such as regional feedback analysis and heat uptake efficacy, may not hold for other forcing scenarios.

Ever since President George W. Bush withdrew the U.S. from the Kyoto Protocol in 2001, many have feared that it was simply too late to save the planet from catastrophic climate change. The election...

Urgent and ambitious climate action is required to avoid catastrophic climate change and consequent health impacts. Political will is a critical component of the ambitious climate action equation. The current level of political will observed for many national governments is considered inadequate, with numerous political leaders yet to commit to climate action commensurate with the projected risks and responsibilities for their respective jurisdictions. Under the leadership of the Obama administration, however, the United States of America arguably provided an example to the contrary. Strategically utilising an available legislative lever, the Obama administration pursued comparatively ambitious climate change mitigation policies, with health as a core motivation. Analysis of Obama-led climate policies and policy-making strategies provides valuable insight into the utility of health as a motivator for climate action. It also reaffirms that strong political leadership constitutes an essential element in the pursuit of increasingly ambitious climate change policies, particularly in the face of strong opposition.

The new age of trade wars could simultaneously affect the worldwide distribution pattern of the economy and environmental emissions. However, previous studies have focused on economic impacts, and on trade liberalization, while little is known about the equilibrium effects of trade barriers on the environment. Using a global computable general equilibrium model and taking the recent anti-trade policies of the Trump administration as an example, this study investigates the possible socio-economic and environmental effects of trade friction. Specifically, this study explores how the implemented six rounds of China–US trade friction and its different long-term development trends affect regional economic output, GHG and air pollutant emissions. Results show that trade barriers harm both countries’ economies and such losses have a certain permanence, while non-participants can benefit indirectly. Trade friction decreases participants’ GHG emissions, modifies global GHG emission distribution patterns, and leads to improved air quality in most countries. If governments continue to impose tariffs, global GHG emissions could counterfactually decrease by up to 5%. However, the change in trade patterns is not conducive to clean energy development in the less-developed regions, including the Middle East, Africa, and Latin America, and emission reductions from trade friction are insufficient to avoid catastrophic climate change.

Can science save humanity? In the face of runaway climate change and massive species extinction, some say that we already know all we need to know to fix these problems: Further research is a distraction and what we need now is action. Others anticipate a feat of technical ingenuity that will catapult us out of our current crisis. Into this fray comes Jurgen Renn, a polymath historian of science, whose research has careened from ancient Chinese mechanics to Einstein9s theory of gravitation to contemporary energy systems. What links these projects is Renn9s fascination with the dynamics by which science changes and changes hands. His new tour de force, The Evolution of Knowledge, addresses all those concerned with science9s fate.

Most countries have signed and ratified an agreement to limit global warming to no more than 2°C because of high risks of harmful effects of climate change above that level. The implications of the 2°C warming limit for limiting eventual CO 2 concentrations in the atmosphere depend on the sensitivity of climate to atmospheric CO 2 . Climate sensitivity can be derived from two fundamentally different and independent methods: from a consideration of physical first principles and from climate changes in the past. Both methods produce a consistent estimate of about 3°C of global average warming per doubling of atmospheric CO 2 . Some simple algebra shows that climate sensitivity provides a limit of about 455 ppm to remain within the internationally agreed warming limit.

The Anthropocene is commonly seen as a period of great potential to further improve human health and other aspects of human well-being, including food security, reflected, for example, by the Sustainable Development Goals. The Intergovernmental Panel on Climate Change (IPCC) is similarly generally optimistic, including with regard to its global food security outlook, apart from far in the future if global temperatures reach 5°C above preindustrial levels. Similarly, the Food and Agricultural Organization has reported falling hunger despite rising global food prices. We challenge this optimism, analyzing datasets and the wider literature. We may be flying blind toward a mountain.

These are my studies of Climate Change and events that are affecting the entire solar system. For decades more and more natural disasters have been occurring and the temperature on earth is increasing. After several studies, I developed a new theory for both Global Warming and many other unpublished matters.

The most extreme risk are those that threaten the entirety of human civilization, known as global catastrophic risks. The very extreme nature of global catastrophes makes them both challenging to analyze and important to address. They are challenging to analyze because they are largely unprecedented and because they involve the entire global human system. They are important to address because they threaten everyone around the world and future generations. Global catastrophic risks also pose some deep dilemmas. One dilemma occurs when actions to reduce global catastrophic risk could harm society in other ways, as in the case of geoengineering to reduce catastrophic climate change risk. Another dilemma occurs when reducing one global catastrophic risk could increase another, as in the case of nuclear power reducing climate change risk while increasing risks from nuclear weapons. The complex, interrelated nature of global catastrophic risk suggests a research agenda in which the full space of risks are assessed in an integrated fashion in consideration of the deep dilemmas and other challenges they pose. Such an agenda can help identify the best ways to manage these most extreme risks and keep human civilization safe.

Can human cooperation expand to the global scale in time to avert catastrophic climate change? Prospects for a sustainable future depend on binding commitments that respect biophysical limits, which in turn depend on political support and global/intergenerational levels of moral concern. Numerous studies in the social sciences indicate that transcending parochial, group-level cooperation to the global scale requires some form of unifying "superordinate goal". This research explores what this transformative humanitarian goal might consist of, and what factors most influence the dynamics of human cooperation. Two quantitative models of cooperative social dynamics are developed and analysed: 1) Historical - analysing the global growth of social insurance provision and the abolition of slavery, including their key structural (macro) predictors; 2) Experimental - analysing the dynamics of cooperation and the consideration of future generations in a multiplayer social dilemma game. Longitudinal growth curve modelling (LGCM) of these models’ data allows many variables to be simultaneously combined into a single group of path coefficients, represented as a network of relationships over time. Preliminary results in the historical model a) confirms the view that social complexity expands more rapidly than cooperation, b) The rate of acceleration of cooperation required to ensure sustainability within the available time greatly exceeds the historical trend. Keywords: cooperation, dynamics, sustainability indicators, co-conn ratio, social movements, cultural evolution, future generations

There is an urgent need for science to inform society about the cost of failure to address the global warming. The challenges offered by global climate change have not been fully recognized by the public and decision making bodies. The severity of climate change has not been taken seriously. It is limited to declarations and propagandas only. Time has come to act globally. The Himalayan Physics Vol. 5, No. 5, Nov. 2014 Page: 98-101

The present day global climate change is fueled by our use of fossil fuels and land use change. The already observed warming and other distinct changes in the climate system stem from these human influences and are ongoing. Due to climate system inertia, a part of the climate system's response to this historical forcing remains to manifest itself, which it will do over time. At the same time, socio-economic forces and trends imply some amount of additional emission and land use change, which compounds our commitment to even more substantial climate change. Cumulative carbon dioxide emissions are the basic determinant of the ultimate amount of anthropogenic climate change. Climate system properties, such as climate sensitivity and the carbon cycle, and also possible initiation of non-linear changes, further shape the amount and nature of the long-term change for any set amount of greenhouse gas emissions. While a changed climate is, in practice, now unavoidable, our commitment to continued climate change can be constrained by reductions of global carbon dioxide emissions, their cessation and/or negative emissions. These alternatives have different implications for the long-term unfolding of these changes, but can all considerably reduce the possibility of very large amounts of change, the need for adaptation and responses to negative impacts. (Less)

The transient climate response to cumulative CO2 emissions (TCRE) is a useful metric of climate warming that directly relates the cause of climate change (cumulative carbon emissions) to the most used index of climate change (global mean near-surface temperature change). In this paper, analytical reasoning is used to investigate why TCRE is near constant over a range of cumulative emissions up to 2000 Pg of carbon. In addition, a climate model of intermediate complexity, forced with a constant flux of CO2 emissions, is used to explore the effect of terrestrial carbon cycle feedback strength on TCRE. The analysis reveals that TCRE emerges from the diminishing radiative forcing from CO2 per unit mass being compensated for by the diminishing ability of the ocean to take up heat and carbon. The relationship is maintained as long as the ocean uptake of carbon, which is simulated to be a function of the CO2 emissions rate, dominates changes in the airborne fraction of carbon. Strong terrestrial carbon cycle feedbacks have a dependence on the rate of carbon emission and, when present, lead to TRCE becoming rate dependent. Despite these feedbacks, TCRE remains roughly constant over the range of the representative concentration pathways and therefore maintains its primary utility as a metric of climate change.

Why Now, Why Us? When I first learned about climate change 15 years ago, I was the medical director of a rural community health center in northern California. I was too busy to do anything more than click on climate change action alerts, but I assumed activists and experts would take care of the problem and we still had plenty of time. When our rivers started to dry up and wildfires filled the sky with smoke, I did more clicking, increased my donations to environmental groups, and waited for a leader to issue instructions. By the time dust storms raised valley fever rates 8-fold and Aedes aegypti mosquitoesdthe most effective vectors for dengue, yellow fever, and chikungunyadfound a new home in California, I realized we were running out of time and that leadership had to come from people like you and me. The window of opportunity to prevent catastrophic climate change is closing. The year 2015 will mark either a historic global accord aimed at dramatically lowering greenhouse gas emissions or our last, lost opportunity to preserve a livable planet for future generations. Our current emissions path, including the proffered international commitments to date, will cause average global temperature to rise more than 2 C above preindustrial temperatures, possibly as soon as mid-century. Health professionals have untapped power to influence what happens at this critical juncture: We are trusted messengers. We have experience translating scientific information into plain language for individuals and communities. We have a growing base of evidence documenting the negative

Large amounts of methane hydrate locked up within marine sediments are vulnerable to climate change. Changes in bottom water temperatures may lead to their destabilization and the release of methane into the water column or even the atmosphere. In a multimodel approach, the possible impact of destabilizing methane hydrates onto global climate within the next century is evaluated. The focus is set on changing bottom water temperatures to infer the response of the global methane hydrate inventory to future climate change. Present and future bottom water temperatures are evaluated by the combined use of hindcast high-resolution ocean circulation simulations and climate modeling for the next century. The changing global hydrate inventory is computed using the parameterized transfer function recently proposed by Wallmann et al. (2012). We find that the present-day world's total marine methane hydrate inventory is estimated to be 1146Gt of methane carbon. Within the next 100years this global inventory may be reduced by ∼0.03% (releasing ∼473Mt methane from the seafloor). Compared to the present-day annual emissions of anthropogenic methane, the amount of methane released from melting hydrates by 2100 is small and will not have a major impact on the global climate. On a regional scale, ocean bottom warming over the next 100years will result in a relatively large decrease in the methane hydrate deposits, with the Arctic and Blake Ridge region, offshore South Carolina, being most affected.

Economic theory has two difficulties to deal with catastrophic climate change events: 1) the impacts are so high that may damage the whole civilization, 2) the impact could only be realized in the far distant future. Discounted utilitarianism fail to explain why society would be willing to prevent catastrophes that could only happen in the far distant future. This paper proves that Chichilnisky’s social welfare criterion could be applied for the issue of catastrophic climate change. Applying this criterion to an “AK” economy with abatement technology, I examine the effects of catastrophic risk on growth and welfare.

Uncharacteristically strong storm activity in the UK during recent years has focused attention once again upon climatic impacts. Rapid climate change, which in turn affects sea surface temperatures (SST), ocean circulation, and wind speed patterns, is most likely contributing to these unprecedented and prolonged storm events. Previous studies focused on individual factors rather than cumulative effects of climate change; however, a knowledge gap exists. Consequently, this quantitative study analysed the current influence of climate change on UK sea surface and mean air temperatures, together with mean wind speeds. It also assessed whether climate change scenarios will create favourable conditions for the genesis of catastrophic hurricanes in the UK using a 2-path analysis (SST, wind speed, temperatures). Accordingly, in situ SST, mean wind speed, and mean temperatures for the period 2000–2014 are analysed. Primary results revealed that increasing trends in regional SST (0.1–0.7 °C), mean temperature (0.4–0.8 °C), and wind speed (0.5–2 m/s) patterns. It is expected that significant changes in climate will cause sea surface temperature increases between 1 and 4 °C, which will accelerate temperature and wind speed further. These adverse changes would negatively affect future UK weather patterns and create positive conditions for the formation of super storms and high winds in the near future, although not necessarily hurricanes.

Copenhagen, Cancun, Durban, Doha, Warsaw, Lima and Paris climate change summits are now lost in obscurity such was their impact. Save for two—Copenhagen and Paris. Copenhagen set out basic requirements for global action, yet it took a further six years of glacial negotiation before the basics could be agreed in Paris. Poor countries are concerned that money promised to them still will not be nearly enough to protect them. Not all of the agreement is legally binding, so future governments could yet renege on their commitments. In fact, the only legally binding part was that countries should report on their progress at a meeting in five years. This section looks at the reality of the climate change summits and what they really mean.

In this Government Initiatives contribution, we present policy recommendations made available to the Scottish Government on how to change Scottish consumers’ relationships with material goods and so contribute to its greenhouse gas emissions targets. Rather than focusing on the individual actions of consumers, we discuss how the underlying neoliberal political narrative must be addressed as it creates the conditions in which invidious materialism can occur. We then propose an alternative conceptualization of marketing that would harness marketing tools and concepts to help build connections between people and stimulate demand for pro-environmental, prosocial, consumption. This function stands in contrast to marketing acting in a way that contributes to the fragmentation of society and degradation of our planet. A series of controls on marketing are then outlined, which seek to facilitate changes to current dominant consumption narratives including using material input labelling as a mechanism to restrict unethical marketing practices. Overall, these ideas represent a more interventionist perspective, but one that we deem necessary when considered against the scale of the task now facing humanity in avoiding catastrophic climate change.

We propose a robust risk management approach to deal with the problem of catastrophic climate change that incorporates both risk and model uncertainty. Using an analytical model of abatement, we show how aversion to model uncertainty influences the optimal level of mitigation. We disentangle the role of preferences from the structure of model uncertainty, which we define by means of a simple measure of disagreement across models. With data from an expert elicitation about climate change catastrophes, we quantify the relative importance of these two effects and calibrate a numerical integrated assessment model of climate change. The results indicate that the structure of model uncertainty, and specifically how model disagreement varies in abatement, is the key driver of optimal abatement and that model uncertainty warrants a higher level of climate change mitigation. This paper was accepted by Manel Baucells, decision analysis.

Solar climate engineering—intentional modification of the planet’s reflectivity—is coming under increasing consideration as a means to counter climate change. At present, it offers the possibility of greatly reducing climate risks, but would pose physical and social risks of its own. This chapter offers an introduction to solar climate engineering, and explores its potential, risks, and legal and regulatory challenges. It also contextualizes these proposals with respect to other emerging technologies and the broader socio-political milieu. The chapter discusses the contours of existing and potential regulation, particularly at the international level. These aspects include regulatory rationales, diverse characteristics of proposed regulatory regimes, difficulties in defining the regulatory target, and the management of uncertainty through precaution. The chapter closes with suggested future research directions in the law and regulation of solar climate engineering.

IT HAS BECOME THE STUFF of daily headlines: the world is in overshoot, with humans wrecking the environment, destroying their own habitat, and undermining the functional integrity of the very biophysical systems upon which they are dependent. Strident warnings of ecological crisis and runaway climate change have gone virtually unheeded for decades. Indeed, the human ecological footprint has expanded exponentially with population and consumption since the early nineteenth century. Brief remissions in recent years are attributable not to deliberate policy correctives but rather to temporary economic setbacks.