Suchergebnisse

A simple question about climate change, with one choice designed to match consensus statements by scientists, was asked on 35 US nationwide, single-state or regional surveys from 2010 to 2015. Analysis of these data (over 28,000 interviews) yields robust and exceptionally well replicated findings on public beliefs about anthropogenic climate change, including regional variations, change over time, demographic bases, and the interacting effects of respondent education and political views. We find that more than half of the US public accepts the scientific consensus that climate change is happening now, caused mainly by human activities. A sizable, politically opposite minority (about 30 to 40%) concede the fact of climate change, but believe it has mainly natural causes. Few (about 10 to 15%) say they believe climate is not changing, or express no opinion. The overall proportions appear relatively stable nationwide, but exhibit place-to-place variations. Detailed analysis of 21 consecutive surveys within one fairly representative state (New Hampshire) finds a mild but statistically significant rise in agreement with the scientific consensus over 2010-2015. Effects from daily temperature are detectable but minor. Hurricane Sandy, which brushed New Hampshire but caused no disaster there, shows no lasting impact on that state's time series-suggesting that non-immediate weather disasters have limited effects. In all datasets political orientation dominates among individual-level predictors of climate beliefs, moderating the otherwise positive effects from education. Acceptance of anthropogenic climate change rises with education among Democrats and Independents, but not so among Republicans. The continuing series of surveys provides a baseline for tracking how future scientific, political, socioeconomic or climate developments impact public acceptance of the scientific consensus.

This paper studies the effects of global warming in a descriptive model of endogenous growth. It is assumed that deviations from the pre-industrial global surface temperature negatively affect aggregate output. The paper studies the effects of varying the tax rate and of different abatement activities on the emission of greenhouse gases and on the growth rate. We study both effects for the long-run balanced growth rate and for the growth rate of GDP on the transition path. Using simulations, it is demonstrated that higher abatement activities may both reduce greenhouse gas emissions and lead to higher growth. Further, the second-best abatement share is computed and the corresponding growth rate as well as the social optimum.

Abstract. On 19 May 2016 the afternoon temperature reached 51.0 °C in Phalodi in the northwest of India – a new record for the highest observed maximum temperature in India. The previous year, a widely reported very lethal heat wave occurred in the southeast, in Andhra Pradesh and Telangana, killing thousands of people. In both cases it was widely assumed that the probability and severity of heat waves in India are increasing due to global warming, as they do in other parts of the world. However, we do not find positive trends in the highest maximum temperature of the year in most of India since the 1970s (except spurious trends due to missing data). Decadal variability cannot explain this, but both increased air pollution with aerosols blocking sunlight and increased irrigation leading to evaporative cooling have counteracted the effect of greenhouse gases up to now. Current climate models do not represent these processes well and hence cannot be used to attribute heat waves in this area. The health effects of heat are often described better by a combination of temperature and humidity, such as a heat index or wet bulb temperature. Due to the increase in humidity from irrigation and higher sea surface temperatures (SSTs), these indices have increased over the last decades even when extreme temperatures have not. The extreme air pollution also exacerbates the health impacts of heat. From these factors it follows that, from a health impact point of view, the severity of heat waves has increased in India. For the next decades we expect the trend due to global warming to continue but the surface cooling effect of aerosols to diminish as air quality controls are implemented. The expansion of irrigation will likely continue, though at a slower pace, mitigating this trend somewhat. Humidity will probably continue to rise. The combination will result in a strong rise in the temperature of heat waves. The high humidity will make health effects worse, whereas decreased air pollution would decrease the impacts.

Extreme weather events such as heat waves, droughts and floods pose risks to the environment and human societies. In East Africa, these events are well-known, reoccurring climate phenomena; however, their impacts and intensity vary across the region and require further study. The East African country of Somalia is highly vulnerable to climatic variability due to its geographic location, which in turn often leads to devastating droughts and floods. The climate impact on human wellbeing and livelihoods is further exacerbated by the absence of a central government coupled with poverty and civil conflict that can escalate – as currently seen – to famine-level situations and large-scale involuntary human mobility. Yet, the extent to which human mobility (measured by internal displacement) can be attributed to extreme weather events and in turn, whether and to what extent extreme weather events and consequently human mobility can be attributed to anthropogenic climate change, has been largely unexplored. Applying a framework based on probabilistic event attribution of extreme weather events, this paper, for the first time, investigates human mobility responses attributed to anthropogenic climate change, exemplifying the state of the art of this method in the context of the East African region. The study shows no attributable link of the April 2020 flood in Somalia (our case study) to anthropogenic climate change. Sparcity of climate observations reveal one of many reasons for a lack of a climate change signal.

Extreme weather events such as heat waves, droughts and floods pose risks to the environment and human societies. In East Africa, these events are well-known, reoccurring climate phenomena; however, their impacts and intensity vary across the region and require further study. The East African country of Somalia is highly vulnerable to climatic variability due to its geographic location, which in turn often leads to devastating droughts and floods. The climate impact on human wellbeing and livelihoods is further exacerbated by the absence of a central government coupled with poverty and civil conflict that can escalate – as currently seen – to famine-level situations and large-scale involuntary human mobility. Yet, the extent to which human mobility (measured by internal displacement) can be attributed to extreme weather events and in turn, whether and to what extent extreme weather events and consequently human mobility can be attributed to anthropogenic climate change, has been largely unexplored. Applying a framework based on probabilistic event attribution of extreme weather events, this paper, for the first time, investigates human mobility responses attributed to anthropogenic climate change, exemplifying the state of the art of this method in the context of the East African region. The study shows no attributable link of the April 2020 flood in Somalia (our case study) to anthropogenic climate change. Sparcity of climate observations reveal one of many reasons for a lack of a climate change signal.

Future scenarios with significant anthropogenic climate change also display large increases in world production of fossil fuels, the principal CO2 emission source. Meanwhile, fossil fuel depletion has also been identified as a future challenge. This chapter reviews the connection between these two issues and concludes that limits to availability of fossil fuels will set a limit for mankind's ability to affect the climate. However, this limit is unclear as various studies have reached quite different conclusions regarding future atmospheric CO2 concentrations caused by fossil fuel limitations. It is concluded that the current set of emission scenarios used by the IPCC and others is perforated by optimistic expectations on future fossil fuel production that are improbable or even unrealistic. The current situation, where climate models largely rely on emission scenarios detached from the reality of supply and its inherent problems is problematic. In fact, it may even mislead planners and politicians into making decisions that mitigate one problem but make the other one worse. It is important to understand that the fossil energy problem and the anthropogenic climate change problem are tightly connected and need to be treated as two interwoven challenges necessitating a holistic solution.

Abstract:
This paper argues that climate change throws down a challenge for the social sciences. They can no longer rely on exclusively social indicators and relative ones, but must include absolute biophysical indicators in their investigations. Accurate analyses of the social causes and consequences of anthropogenic climate change require that they capture the complexity of lay and scientific knowledge, and the nuances of uncertainty, of nature, and of language rather than relying on oversimplified notions. The paper examines whether resilience is a protective strategy under uncertainty and whether disasters are likely to impel mitigation of global warming. It assesses lofty post-carbon utopia discourse and suggests instead the comparative analysis of successful and unsuccessful societies in preventing anthropogenic global warming. To illustrate such an analysis, the paper sketches a study of the different developmental channels of Northern Europe and North America.