Marine heatwaves have been shown to be increasing in frequency, duration and intensity over the past several decades. Are these changes related to rising mean temperatures, changes to temperature ...variability, or a combination of the two? Here we investigate this question using satellite observations of sea surface temperature (SST) covering 36 years (1982–2017). A statistical climate model is used to simulate SST time series, including realistic variability based on an autoregressive model fit to observations, with specified trends in mean and variance. These simulated SST time series are then used to test whether observed trends in marine heatwave properties can be explained by changes in either mean or variability in SST, or both. We find changes in mean SST to be the dominant driver of the increasing frequency of marine heatwave days over approximately 2/3 of the ocean; while it is the dominant driver of changes in marine heatwave intensity (temperature anomaly) over approximately 1/3 of the ocean. We also find that changes in mean SST explain changes in both MHW properties over a significantly larger proportion of the world’s ocean than changes in SST variance. The implication is that given the high confidence of continued mean warming throughout the twenty-first century due to anthropogenic climate change we can expect the historical trends in marine heatwave properties to continue over the coming decades.
Local government is the hidden leviathan of American politics: it accounts for nearly a tenth of gross domestic product, it collects nearly as much in taxes as the federal government, and its ...decisions have an enormous impact on Americans' daily lives. Yet political scientists have few explanations for how people vote in local elections, particularly in the smaller cities, towns, and suburbs where most Americans live. Drawing on a wide variety of data sources and case studies, this book offers the first comprehensive analysis of electoral politics in America's municipalities.
Arguing that current explanations of voting behavior are ill suited for most local contests, Eric Oliver puts forward a new theory that highlights the crucial differences between local, state, and national democracies. Being small in size, limited in power, and largely unbiased in distributing their resources, local governments are "managerial democracies" with a distinct style of electoral politics. Instead of hinging on the partisanship, ideology, and group appeals that define national and state elections, local elections are based on the custodial performance of civic-oriented leaders and on their personal connections to voters with similarly deep community ties. Explaining not only the dynamics of local elections, Oliver's findings also upend many long-held assumptions about community power and local governance, including the importance of voter turnout and the possibilities for grassroots political change.
Marine Heatwaves Oliver, Eric C J; Benthuysen, Jessica A; Darmaraki, Sofia ...
Annual review of marine science,
01/2021, Volume:
13
Journal Article
Peer reviewed
Ocean temperature variability is a fundamental component of the Earth's climate system, and extremes in this variability affect the health of marine ecosystems around the world. The study of marine ...heatwaves has emerged as a rapidly growing field of research, given notable extreme warm-water events that have occurred against a background trend of global ocean warming. This review summarizes the latest physical and statistical understanding of marine heatwaves based on how they are identified, defined, characterized, and monitored through remotely sensed and in situ data sets. We describe the physical mechanisms that cause marine heatwaves, along with their global distribution, variability, and trends. Finally, we discuss current issues in this developing research area, including considerations related to thechoice of climatological baseline periods in defining extremes and how to communicate findings in the context of societal needs.
Categorizing and Naming MARINE HEATWAVES Hobday, Alistair J.; Oliver, Eric C. J.; Gupta, Alex Sen ...
Oceanography (Washington, D.C.),
06/2018, Volume:
31, Issue:
2
Journal Article
Peer reviewed
Open access
Considerable attention has been directed at understanding the consequences and impacts of long-term anthropogenic climate change. Discrete, climatically extreme events such as cyclones, floods, and ...heatwaves can also significantly affect regional environments and species, including humans. Climate change is expected to intensify these events and thus exacerbate their effects. Climatic extremes also occur in the ocean, and recent decades have seen many high-impact marine heatwaves (MHWs)—anomalously warm water events that may last many months and extend over thousands of square kilometers. A range of biological, economic, and political impacts have been associated with the more intense MHWs, and measuring the severity of these phenomena is becoming more important. Progress in understanding and public awareness will be facilitated by consistent description of these events. Here, we propose a detailed categorization scheme for MHWs that builds on a recently published classification, combining elements from schemes that describe atmospheric heatwaves and hurricanes. Category I, II, III, and IV MHWs are defined based on the degree to which temperatures exceed the local climatology and illustrated for 10 MHWs. While there is a long-term increase in the occurrence frequency of all MHW categories, the largest trend is a 24% increase in the area of the ocean where strong (Category II) MHWs occur. Use of this scheme can help explain why biological impacts associated with different MHWs can vary widely and provides a consistent way to compare events. We also propose a simple naming convention based on geography and year that would further enhance scientific and public awareness of these marine events.
Although conspiracy theories have long been a staple of American political culture, no research has systematically examined the nature of their support in the mass public. Using four nationally ...representative surveys, sampled between 2006 and 2011, we find that half of the American public consistently endorses at least one conspiracy theory and that many popular conspiracy theories are differentiated along ideological and anomic dimensions. In contrast with many theoretical speculations, we do not find conspiracism to be a product of greater authoritarianism, ignorance, or political conservatism. Rather, the likelihood of supporting conspiracy theories is strongly predicted by a willingness to believe in other unseen, intentional forces and an attraction to Manichean narratives. These findings both demonstrate the widespread allure of conspiracy theories as political explanations and offer new perspectives on the forces that shape mass opinion and American political culture.
Heatwaves are important climatic extremes in atmospheric and oceanic systems that can have devastating and long-term impacts on ecosystems, with subsequent socioeconomic consequences. Recent ...prominent marine heatwaves have attracted considerable scientific and public interest. Despite this, a comprehensive assessment of how these ocean temperature extremes have been changing globally is missing. Using a range of ocean temperature data including global records of daily satellite observations, daily in situ measurements and gridded monthly in situ-based data sets, we identify significant increases in marine heatwaves over the past century. We find that from 1925 to 2016, global average marine heatwave frequency and duration increased by 34% and 17%, respectively, resulting in a 54% increase in annual marine heatwave days globally. Importantly, these trends can largely be explained by increases in mean ocean temperatures, suggesting that we can expect further increases in marine heatwave days under continued global warming.
The Tasman Sea off southeast Australia exhibited its longest and most intense marine heatwave ever recorded in 2015/16. Here we report on several inter-related aspects of this event: observed ...characteristics, physical drivers, ecological impacts and the role of climate change. This marine heatwave lasted for 251 days reaching a maximum intensity of 2.9 °C above climatology. The anomalous warming is dominated by anomalous convergence of heat linked to the southward flowing East Australian Current. Ecosystem impacts range from new disease outbreaks in farmed shellfish, mortality of wild molluscs and out-of-range species observations. Global climate models indicate it is very likely to be that the occurrence of an extreme warming event of this duration or intensity in this region is respectively ≥330 times and ≥6.8 times as likely to be due to the influence of anthropogenic climate change. Climate projections indicate that event likelihoods will increase in the future, due to increasing anthropogenic influences.
Despite the wide application of the label "populist" in the 2016 election cycle, there has been little systematic evidence that this election is distinctive in its populist appeal. Looking at ...historical trends, contemporary rhetoric, and public opinion data, we find that populism is an appropriate descriptor of the 2016 election and that Donald Trump stands out in particular as the populist par excellence. Historical data reveal a large "representation gap" that typically accompanies populist candidates. Content analysis of campaign speeches shows that Trump, more so than any other candidate, employs a rhetoric that is distinctive in its simplicity, anti-elitism, and collectivism. Original survey data show that Trump's supporters are distinctive in their unique combination of anti-expertise, anti-elitism, and pronationalist sentiments. Together, these findings highlight the distinctiveness of populism as a mechanism of political mobilization and the unusual character of the 2016 race.
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