2008, Archer, D., Brovkin, V.

The notion is pervasive in the climate science community and in the public at large that the climate impacts of fossil fuel CO2 release will only persist for a few centuries. This conclusion has no basis in theory or models of the atmosphere/ocean carbon cycle, which we review here. The largest fraction of the CO2 recovery will take place on time scales of centuries, as CO2 invades the ocean, but a significant fraction of the fossil fuel CO2, ranging in published models in the literature from 20-60%, remains airborne for a thousand years or longer. Ultimate recovery takes place on time scales of hundreds of thousands of years, a geologic longevity typically associated in public perceptions with nuclear waste. The glacial/interglacial climate cycles demonstrate that ice sheets and sea level respond dramatically to millennial-timescale changes in climate forcing. There are also potential positive feedbacks in the carbon cycle, including methane hydrates in the ocean, and peat frozen in permafrost, that are most sensitive to the long tail of the fossil fuel CO2 in the atmosphere. © 2008 The Author(s).

2009, Brovkin, V., Petoukhov, V., Claussen, M., Bauer, E., Archer, D., Jaeger, C.

We use a coupled climate-carbon cycle model of intermediate complexity to investigate scenarios of stratospheric sulfur injections as a measure to compensate for CO2-induced global warming. The baseline scenario includes the burning of 5,000 GtC of fossil fuels. A full compensation of CO2-induced warming requires a load of about 13 MtS in the stratosphere at the peak of atmospheric CO2 concentration. Keeping global warming below 2°C reduces this load to 9 MtS. Compensation of CO 2 forcing by stratospheric aerosols leads to a global reduction in precipitation, warmer winters in the high northern latitudes and cooler summers over northern hemisphere landmasses. The average surface ocean pH decreases by 0.7, reducing the calcifying ability of marine organisms. Because of the millennial persistence of the fossil fuel CO2 in the atmosphere, high levels of stratospheric aerosol loading would have to continue for thousands of years until CO2 was removed from the atmosphere. A termination of stratospheric aerosol loading results in abrupt global warming of up to 5°C within several decades, a vulnerability of the Earth system to technological failure. © 2008 The Author(s).

2014, O'Neill, B.C., Kriegler, E., Riahi, K., Ebi, K.L., Hallegatte, S., Carter, T.R., Mathur, R., van Vuuren, D.P.

The new scenario framework for climate change research envisions combining pathways of future radiative forcing and their associated climate changes with alternative pathways of socioeconomic development in order to carry out research on climate change impacts, adaptation, and mitigation. Here we propose a conceptual framework for how to define and develop a set of Shared Socioeconomic Pathways (SSPs) for use within the scenario framework. We define SSPs as reference pathways describing plausible alternative trends in the evolution of society and ecosystems over a century timescale, in the absence of climate change or climate policies. We introduce the concept of a space of challenges to adaptation and to mitigation that should be spanned by the SSPs, and discuss how particular trends in social, economic, and environmental development could be combined to produce such outcomes. A comparison to the narratives from the scenarios developed in the Special Report on Emissions Scenarios (SRES) illustrates how a starting point for developing SSPs can be defined. We suggest initial development of a set of basic SSPs that could then be extended to meet more specific purposes, and envision a process of application of basic and extended SSPs that would be iterative and potentially lead to modification of the original SSPs themselves.

2011, Meinshausen, M., Smith, S.J., Calvin, K., Daniel, J.S., Kainuma, M.L.T., Lamarque, J., Matsumoto, K., Montzka, S.A., Raper, S.C.B., Riahi, K., Thomson, A., Velders, G.J.M., van Vuuren, D.P.P.

We present the greenhouse gas concentrations for the Representative Concentration Pathways (RCPs) and their extensions beyond 2100, the Extended Concentration Pathways (ECPs). These projections include all major anthropogenic greenhouse gases and are a result of a multi-year effort to produce new scenarios for climate change research. We combine a suite of atmospheric concentration observations and emissions estimates for greenhouse gases (GHGs) through the historical period (1750-2005) with harmonized emissions projected by four different Integrated Assessment Models for 2005-2100. As concentrations are somewhat dependent on the future climate itself (due to climate feedbacks in the carbon and other gas cycles), we emulate median response characteristics of models assessed in the IPCC Fourth Assessment Report using the reduced-complexity carbon cycle climate model MAGICC6. Projected 'best-estimate' global-mean surface temperature increases (using inter alia a climate sensitivity of 3°C) range from 1.5°C by 2100 for the lowest of the four RCPs, called both RCP3-PD and RCP2. 6, to 4.5°C for the highest one, RCP8. 5, relative to pre-industrial levels. Beyond 2100, we present the ECPs that are simple extensions of the RCPs, based on the assumption of either smoothly stabilizing concentrations or constant emissions: For example, the lower RCP2. 6 pathway represents a strong mitigation scenario and is extended by assuming constant emissions after 2100 (including net negative CO2 emissions), leading to CO2 concentrations returning to 360 ppm by 2300. We also present the GHG concentrations for one supplementary extension, which illustrates the stringent emissions implications of attempting to go back to ECP4. 5 concentration levels by 2250 after emissions during the 21st century followed the higher RCP6 scenario. Corresponding radiative forcing values are presented for the RCP and ECPs.

2013, Held, H., Gerstengarbe, F.-W., Pardowitz, T., Pinto, J.G., Ulbrich, U., Born, K., Donat, M.G., Karremann, M.K., Leckebusch, G.C., Ludwig, P., Nissen, K.M., Österle, H., Prahl, B.F., Werner, P.C., Befort, D.J., Burghoff, O.

We present projections of winter storm-induced insured losses in the German residential building sector for the 21st century. With this aim, two structurally most independent downscaling methods and one hybrid downscaling method are applied to a 3-member ensemble of ECHAM5/MPI-OM1 A1B scenario simulations. One method uses dynamical downscaling of intense winter storm events in the global model, and a transfer function to relate regional wind speeds to losses. The second method is based on a reshuffling of present day weather situations and sequences taking into account the change of their frequencies according to the linear temperature trends of the global runs. The third method uses statistical-dynamical downscaling, considering frequency changes of the occurrence of storm-prone weather patterns, and translation into loss by using empirical statistical distributions. The A1B scenario ensemble was downscaled by all three methods until 2070, and by the (statistical-) dynamical methods until 2100. Furthermore, all methods assume a constant statistical relationship between meteorology and insured losses and no developments other than climate change, such as in constructions or claims management. The study utilizes data provided by the German Insurance Association encompassing 24 years and with district-scale resolution. Compared to 1971-2000, the downscaling methods indicate an increase of 10-year return values (i.e. loss ratios per return period) of 6-35 % for 2011-2040, of 20-30 % for 2041-2070, and of 40-55 % for 2071-2100, respectively. Convolving various sources of uncertainty in one confidence statement (data-, loss model-, storm realization-, and Pareto fit-uncertainty), the return-level confidence interval for a return period of 15 years expands by more than a factor of two. Finally, we suggest how practitioners can deal with alternative scenarios or possible natural excursions of observed losses.

2018, Vicedo-Cabrera, Ana Maria, Guo, Yuming, Sera, Francesco, Huber, Veronika, Schleussner, Carl-Friedrich, Mitchell, Dann, Tong, Shilu, de Sousa Zanotti Stagliorio Coelho, Micheline, Saldiva, Paulo Hilario Nascimento, Lavigne, Eric, Matus Correa, Patricia, Valdes Ortega, Nicolas, Kan, Haidong, Osorio, Samuel, Kyselý, Jan, Urban, Aleš, Jaakkola, Jouni J. K., Ryti, Niilo R. I., Pascal, Mathilde, Goodman, Patrick G., Zeka, Ariana, Michelozzi, Paola, Scortichini, Matteo, Hashizume, Masahiro, Honda, Yasushi, Hurtado-Diaz, Magali, Cruz, Julio, Seposo, Xerxes, Kim, Ho, Tobias, Aurelio, Íñiguez, Carmen, Forsberg, Bertil, Åström, Daniel Oudin, Ragettli, Martina S., Röösli, Martin, Guo, Yue Leon, Wu, Chang-fu, Zanobetti, Antonella, Schwartz, Joel, Bell, Michelle L., Dang, Tran Ngoc, Do Van, Dung, Heaviside, Clare, Vardoulakis, Sotiris, Hajat, Shakoor, Haines, Andy, Armstrong, Ben, Ebi, Kristie L., Gasparrini, Antonio

The Paris Agreement binds all nations to undertake ambitious efforts to combat climate change, with the commitment to “hold warming well below 2 °C in global mean temperature (GMT), relative to pre-industrial levels, and to pursue efforts to limit warming to 1.5 °C”. The 1.5 °C limit constitutes an ambitious goal for which greater evidence on its benefits for health would help guide policy and potentially increase the motivation for action. Here we contribute to this gap with an assessment on the potential health benefits, in terms of reductions in temperature-related mortality, derived from the compliance to the agreed temperature targets, compared to more extreme warming scenarios. We performed a multi-region analysis in 451 locations in 23 countries with different climate zones, and evaluated changes in heat and cold-related mortality under scenarios consistent with the Paris Agreement targets (1.5 and 2 °C) and more extreme GMT increases (3 and 4 °C), and under the assumption of no changes in demographic distribution and vulnerability. Our results suggest that limiting warming below 2 °C could prevent large increases in temperature-related mortality in most regions worldwide. The comparison between 1.5 and 2 °C is more complex and characterized by higher uncertainty, with geographical differences that indicate potential benefits limited to areas located in warmer climates, where direct climate change impacts will be more discernible.

2021, Hermann, Erik

The increasing humanization and emotional intelligence of AI applications have the potential to induce consumers’ attachment to AI and to transform human-to-AI interactions into human-to-human-like interactions. In turn, consumer behavior as well as consumers’ individual and social lives can be affected in various ways. Following this reasoning, I illustrate the implications and research opportunities related to consumers’ (potential) attachment to humanized AI applications along the stages of the consumption process.

2013, Stone, D., Auffhammer, M., Carey, M., Hansen, G., Huggel, C., Cramer, W., Lobell, D., Molau, U., Solow, A., Tibig, L., Yohe, G.

Anthropogenic climate change has triggered impacts on natural and human systems world-wide, yet the formal scientific method of detection and attribution has been only insufficiently described. Detection and attribution of impacts of climate change is a fundamentally cross-disciplinary issue, involving concepts, terms, and standards spanning the varied requirements of the various disciplines. Key problems for current assessments include the limited availability of long-term observations, the limited knowledge on processes and mechanisms involved in changing environmental systems, and the widely different concepts applied in the scientific literature. In order to facilitate current and future assessments, this paper describes the current conceptual framework of the field and outlines a number of conceptual challenges. Based on this, it proposes workable cross-disciplinary definitions, concepts, and standards. The paper is specifically intended to serve as a baseline for continued development of a consistent cross-disciplinary framework that will facilitate integrated assessment of the detection and attribution of climate change impacts.

2008, Jaeger, C., Schellnhuber, H.J., Brovkin, V.

The Stern Review has played an enormous role in making the world of business aware of the challenge of long-term climate change. In order to make real progress on the basis of this awareness, it is important to pay attention to the difference between human suffering and losses of gross domestic product (GDP). The Review has compared climate change to experiences of suffering like World War I. That war, however, hardly affected global GDP. The long-term damages to be expected from business-as-usual greenhouse gas emissions include loss of the coastal cities of the world over the next millennia. This would be an act of unprecedented barbarism, regardless of whether it would slow down economic growth or perhaps even accelerate it. Business leaders worried about climate change need to pay attention to the tensions between ethical and economic concerns. Otherwise, a credibility crisis threatens global climate policy. An important step to establish the credibility needed for effective climate policy will be to gradually move towards a regime where emission permits are auctioned, not handed out as hidden subsidies. The revenues generated by permit auctions should be used to establish a global system of regional climate funds. © 2008 The Author(s).

2014, Fytterer, T., Arras, C., Hoffmann, P., Jacobi, C.

Global Positioning System radio occultation measurements by FORMOsa SATellite mission-3/Constellation Observing System for Meteorology, Ionosphere and Climate satellites were used to analyse the characteristics of the 8-h oscillation in sporadic E (E S ) layers. Six-year averages based on the 3-monthly mean zonal means from December 2006 to November 2012 were constructed for the amplitude of the terdiurnal oscillation in the occurrence frequency of E S . A global distribution from 60° S to 60° N is given, revealing two peaks above 100 km during solstice with one maximum at low and midlatitudes (approximately 10° to 40°) in each hemisphere. During equinox, the global distribution is marked by two dominant peaks centred at midlatitudes, while an additional weak maximum is located at very low southern latitudes. The seasonal characteristics around 110 km reveal large values during equinox at low and midlatitudes (<40° N), while further peaks occur in April at >40° S and in July near 30° S. The pattern around 90 km is dominated by a broad peak between 20° and 30° S from March to September. Comparisons with the terdiurnal oscillation in the neutral atmosphere derived from zonal wind and vertical zonal wind shear simulated with a circulation model of the middle atmosphere, as well as with satellite observations of the terdiurnal tide in temperature, fit quite well for the results above 100 km, but do not show agreement for lower altitudes.