scholarly journals Influence of Anthropogenic Climate Change on Planetary Wave Resonance and Extreme Weather Events

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Michael E. Mann ◽  
Stefan Rahmstorf ◽  
Kai Kornhuber ◽  
Byron A. Steinman ◽  
Sonya K. Miller ◽  
...  
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Climate Model ◽  
High Amplitude ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
Weather Events ◽  
Zonal Wavenumber ◽  
Climate Model Simulations ◽  
Favorable Conditions

Abstract Persistent episodes of extreme weather in the Northern Hemisphere summer have been shown to be associated with the presence of high-amplitude quasi-stationary atmospheric Rossby waves within a particular wavelength range (zonal wavenumber 6–8). The underlying mechanistic relationship involves the phenomenon of quasi-resonant amplification (QRA) of synoptic-scale waves with that wavenumber range becoming trapped within an effective mid-latitude atmospheric waveguide. Recent work suggests an increase in recent decades in the occurrence of QRA-favorable conditions and associated extreme weather, possibly linked to amplified Arctic warming and thus a climate change influence. Here, we isolate a specific fingerprint in the zonal mean surface temperature profile that is associated with QRA-favorable conditions. State-of-the-art (“CMIP5”) historical climate model simulations subject to anthropogenic forcing display an increase in the projection of this fingerprint that is mirrored in multiple observational surface temperature datasets. Both the models and observations suggest this signal has only recently emerged from the background noise of natural variability.

scholarly journals On the attribution of the impacts of extreme weather events to anthropogenic climate change

2021 ◽  
Author(s):  
Sarah E Perkins-Kirkpatrick ◽  
Daithi Stone ◽  
Dann M. Mitchell ◽  
Suzanne M. Rosier ◽  
Andrew David King ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Model ◽  
Anthropogenic Impacts ◽  
Extreme Weather ◽  
Anthropogenic Climate Change ◽  
Extreme Weather Events ◽  
Climate Change Signal ◽  
Care Needs ◽  
Weather Events ◽  
The Impact

Abstract Investigations into the role of anthropogenic climate change in extreme weather events are now starting to extend into analysis of anthropogenic impacts on non-climate (e.g. socio-economic) systems. However, care needs to be taken when making this extension, because methodological choices regarding extreme weather attribution can become crucial when considering the events’ impacts. The fraction of attributable risk (FAR) method, useful in extreme weather attribution research, has a very specific interpretation concerning a class of events, and there is potential to misinterpret results from weather event analyses as being applicable to specific events and their impact outcomes. Using two case studies of meteorological extremes and their impacts, we argue that FAR is not generally appropriate when estimating the magnitude of the anthropogenic signal behind a specific impact. Attribution assessments on impacts should always be carried out in addition to assessment of the associated meteorological event, since it cannot be assumed that the anthropogenic signal behind the weather is equivalent to the signal behind the impact because of lags and nonlinearities in the processes through which the impact system reacts to weather. Whilst there are situations where employing FAR to understand the climate change signal behind a class of impacts is useful (e.g. “system breaking” events), more useful results will generally be produced if attribution questions on specific impacts are reframed to focus on changes in the impact return value and magnitude across large samples of factual and counterfactual climate model and impact simulations. We advocate for constant interdisciplinary collaboration as essential for effective and robust impact attribution assessments.

scholarly journals Projected changes in persistent extreme summer weather events: The role of quasi-resonant amplification

2018 ◽  
Vol 4 (10) ◽  
pp. eaat3272 ◽  
Author(s):  
Michael E. Mann ◽  
Stefan Rahmstorf ◽  
Kai Kornhuber ◽  
Byron A. Steinman ◽  
Sonya K. Miller ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Climate Models ◽  
Climate Model ◽  
Coupled Model ◽  
High Amplitude ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
Anthropogenic Aerosols ◽  
Pronounced Increase ◽  
Weather Events

Persistent episodes of extreme weather in the Northern Hemisphere summer have been associated with high-amplitude quasi-stationary atmospheric Rossby waves, with zonal wave numbers 6 to 8 resulting from the phenomenon of quasi-resonant amplification (QRA). A fingerprint for the occurrence of QRA can be defined in terms of the zonally averaged surface temperature field. Examining state-of-the-art [Coupled Model Intercomparison Project Phase 5 (CMIP5)] climate model projections, we find that QRA events are likely to increase by ~50% this century under business-as-usual carbon emissions, but there is considerable variation among climate models. Some predict a near tripling of QRA events by the end of the century, while others predict a potential decrease. Models with amplified Arctic warming yield the most pronounced increase in QRA events. The projections are strongly dependent on assumptions regarding the nature of changes in radiative forcing associated with anthropogenic aerosols over the next century. One implication of our findings is that a reduction in midlatitude aerosol loading could actually lead to Arctic de-amplification this century, ameliorating potential increases in persistent extreme weather events.

Forecast-based attribution of a winter heatwave within the limit of predictability

2021 ◽  
Vol 118 (49) ◽  
pp. e2112087118
Author(s):  
Nicholas J. Leach ◽  
Antje Weisheimer ◽  
Myles R. Allen ◽  
Tim Palmer
Keyword(s):  
Climate Change ◽  
Climate Model ◽  
Extreme Event ◽  
False Negative ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
Climate Change Signal ◽  
Weather Events ◽  
Medium Range ◽  
The Impact

Attribution of extreme weather events has expanded rapidly as a field over the past decade. However, deficiencies in climate model representation of key dynamical drivers of extreme events have led to some concerns over the robustness of climate model–based attribution studies. It has also been suggested that the unconditioned risk-based approach to event attribution may result in false negative results due to dynamical noise overwhelming any climate change signal. The “storyline” attribution framework, in which the impact of climate change on individual drivers of an extreme event is examined, aims to mitigate these concerns. Here we propose a methodology for attribution of extreme weather events using the operational European Centre for Medium-Range Weather Forecasts (ECMWF) medium-range forecast model that successfully predicted the event. The use of a successful forecast ensures not only that the model is able to accurately represent the event in question, but also that the analysis is unequivocally an attribution of this specific event, rather than a mixture of multiple different events that share some characteristic. Since this attribution methodology is conditioned on the component of the event that was predictable at forecast initialization, we show how adjusting the lead time of the forecast can flexibly set the level of conditioning desired. This flexible adjustment of the conditioning allows us to synthesize between a storyline (highly conditioned) and a risk-based (relatively unconditioned) approach. We demonstrate this forecast-based methodology through a partial attribution of the direct radiative effect of increased CO2 concentrations on the exceptional European winter heatwave of February 2019.

scholarly journals Weather Literacy in Times of Climate Change

2020 ◽  
Vol 12 (3) ◽  
pp. 435-452 ◽  
Author(s):  
Nadine Fleischhut ◽  
Stefan M. Herzog ◽  
Ralph Hertwig
Keyword(s):  
Climate Change ◽  
Weather Conditions ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
The Public ◽  
Weather Events ◽  
The Future ◽  
Nationally Representative ◽  
And Migration ◽  
Weather Risks

AbstractAs climate change unfolds, extreme weather events are on the rise worldwide. According to experts, extreme weather risks already outrank those of terrorism and migration in likelihood and impact. But how well does the public understand weather risks and forecast uncertainty and thus grasp the amplified weather risks that climate change poses for the future? In a nationally representative survey (N = 1004; Germany), we tested the public’s weather literacy and awareness of climate change using 62 factual questions. Many respondents misjudged important weather risks (e.g., they were unaware that UV radiation can be higher under patchy cloud cover than on a cloudless day) and struggled to connect weather conditions to their impacts (e.g., they overestimated the distance to a thunderstorm). Most misinterpreted a probabilistic forecast deterministically, yet they strongly underestimated the uncertainty of deterministic forecasts. Respondents with higher weather literacy obtained weather information more often and spent more time outside but were not more educated. Those better informed about climate change were only slightly more weather literate. Overall, the public does not seem well equipped to anticipate weather risks in the here and now and may thus also fail to fully grasp what climate change implies for the future. These deficits in weather literacy highlight the need for impact forecasts that translate what the weather may be into what the weather may do and for transparent communication of uncertainty to the public. Boosting weather literacy may help to improve the public’s understanding of weather and climate change risks, thereby fostering informed decisions and mitigation support.

scholarly journals Policy options for addressing climate change, with a focus on ecosystem based adaptation: a case study of Guyana

2021 ◽  
Author(s):  
Ramesh Lilwah
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Public Awareness ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
Weather Events ◽  
Resource Sector ◽  
Adaptation Method ◽  
Impacts Of Climate Change

Close to ninety percent of Guyana‟s population live along a low lying coastal plain, which is below sea level and very vulnerable to the impacts of climate change. While the national government has not yet developed a comprehensive climate policy, the potential impacts of climate change is considered in several sectoral policies, much of which emphasize mitigation, with little focus on adaptation. This research examined the current priorities for adaptation by a review of the policies within the natural resource sector to identify opportunities for adaptation, especially ecosystem based adaptation. A Diagnostic Adaptation Framework (DAF) was used to help identify approaches to address a given adaptation challenge with regards to needs, measures and options. A survey questionnaire was used to support the policy reviews and identified four key vulnerabilities: coastal floods; sea level rise; drought and extreme weather events. The application of the DAF in selecting an adaptation method suggests the need for more data on drought and extreme weather events. Coastal flooding is addressed, with recognized need for more data and public awareness for ecosystem based adaptation

scholarly journals Projecting Climate Change Impacts on Mediterranean Finfish Production: A Case Study in Greece.

2021 ◽  
Author(s):  
Orestis Stavrakidis-Zachou ◽  
Konstadia Lika ◽  
Panagiotis Anastasiadis ◽  
Nikos Papandroulakis
Keyword(s):  
Climate Change ◽  
Climate Change Impacts ◽  
Population Level ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
Mediterranean Country ◽  
Farm Level ◽  
Weather Events ◽  
The Future ◽  
The Individual

Abstract Finfish aquaculture in the Mediterranean Sea faces increasing challenges due to climate change while potential adaptation requires a robust assessment of the arising threats and opportunities. This paper presents an approach developed to investigate effects of climate drivers on Greek aquaculture, a representative Mediterranean country with a leading role in the sector. Using a farm level approach, Dynamic Energy Budget models for European seabass and meagre were developed and environmental forcing was used to simulate changes in production and farm profitability under IPCC scenarios RCP45 and RCP85. The effects of temperature and extreme weather events at the individual and farm level were considered along with that of husbandry parameters such as stocking timing, market size, and farm location (inshore, offshore) for nine regions. The simulations suggest that at the individual level fish may benefit from warmer temperatures in the future in terms of growth, thus reaching commercial sizes faster, while the husbandry parameters may have as large an effect on growth as the projected shifts in climatic cues. However, this benefit will be largely offset by the adverse effects of extreme weather events at the population level. Such events will be more frequent in the future and, depending on the intensity one assigns to them, they could cause losses in biomass and farm profits that range from mild to detrimental for the industry. Overall, these results provide quantification of some of the potential threats for an important aquaculture sector while suggesting possibilities to benefit from emerging opportunities. Therefore, they could contribute to improving the sector’s readiness for tackling important challenges in the future.

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