Climatic Change

Hermansen, Erlend A. T.; Sundqvist, Göran

doi: 10.1007/s10584-022-03309-ypmid: N/A

It is widely accepted that the Paris Agreement implies a shift in global climate mitigation policy from a top-down approach focused on global distribution of emission cuts and international cost-effectiveness to a bottom-up approach based on national efforts. Less is known about how this shift at the global level trickles down and manifests in national climate mitigation policy. Norway is in this respect an interesting example, since it has long been portrayed as an important driver of an international top-down approach. In this paper, we demonstrate that Norwegian policy cannot be characterised as a ‘pure’ top-down regime; policy instruments and measures directed at specific technology investments and deployment to complement cost-effective (international) policy instruments have been an explicit government ambition for a long time. Second, by using the case of biofuels, we analyse how the two approaches have been combined in practice over the past decade. Using the notion of ‘hybrid management’, we demonstrate that the top-down approach has left a lasting imprint on Norwegian mitigation policy, but also that this approach has increasingly been challenged by bottom-up thinking, leaving Norwegian climate mitigation policy as a contested hybrid of policy approaches. We conclude that inadequate institutional arrangements for productively managing the tensions between the two approaches have hampered progress in Norwegian policy in curbing domestic emissions. We expect that Norwegian climate mitigation will become increasingly hybridised in the coming decades, and suggest that cultivating hybridisation can be a productive approach for policy progress.

Kouhi, Soroush; Hashemi, M. Reza; Spaulding, Malcolm; Hara, Tetsu

doi: 10.1007/s10584-022-03342-xpmid: N/A

Storm-surge models are commonly used to assess the impacts of hurricanes and coastal storms in coastal areas. Including the impact of the projected future sea level rise (SLR) in these models is a necessary step for a realistic flood risk assessment. Commonly, SLR is superimposed linearly on the simulated water elevation. This approach, while efficient, may lead to inaccuracies. Furthermore, developing a new model with updated data (e.g., boundary conditions, bathymetry) that include the effects of SLR (i.e., nonlinear approach) is time consuming. We compare the linear and nonlinear approaches to include the effect of SLR in predicting maximum water/flood elevations (MWE) as a result of storm surge. After a simplified theoretical analysis, a number of idealized cases based on the typical coastal bodies of water are modeled to assess the impact of SLR on MWE using the linear superposition and nonlinear approaches. Additionally, two case studies are carried out: Narragansett Bay, RI, and Long Island Sound, CT (USA). Results show that for the idealized cases with variable depth, in general, the linear superposition of SLR to MWE is conservative (i.e., predicts a larger flood elevation) relative to the nonlinear approach. However, if a constant depth is considered, results are not consistent (i.e., linear superposition can overestimate or underestimate MWE, and the results depended on the geometry). The simulated MWE from the Narragansett Bay simulation confirms the outcome of idealized cases showing that linear assumption is conservative up to 10% relative to the nonlinear approach. For this study, Hurricane Sandy and a synthetic storm from the US Army Corps of Engineers North Atlantic Comprehensive Coastal Study (NACCS) dataset are simulated. Long Island Sound model results are also consistent with the idealized case. In general, based on the results of the idealized and real case studies, a discrepancy of up to 10% between the linear and nonlinear approaches is expected in estimation of MWE which can be under- or over-estimation of flood elevation, depending on the geometry.

Alizadeh, Omid; Babaei, Morteza

doi: 10.1007/s10584-022-03316-zpmid: N/A

Quantifying seasonally varying temperature and precipitation changes is important, particularly in relatively dry regions that are highly vulnerable to climate change. The ERA5 dataset is used here to examine long-term (1979–2020) near-surface temperature and precipitation changes and to understand the driving mechanisms for precipitation changes over Southwest Asia in different seasons. Precipitation and its changes are also analysed based on the CRU dataset. Significant warming trends with strong seasonal and regional differences are identified over Southwest Asia, with the greatest warming trend in spring, followed in decreasing order by winter, summer, and autumn. Mountain temperatures have also increased much faster than other regions in Southwest Asia, particularly in winter and spring. Based on both ERA5 and CRU, precipitation has significantly decreased over parts of southwestern and eastern Iran and southwestern Pakistan in winter but has significantly increased over the Caucasus in spring. Precipitation has not changed significantly over Southwest Asia in summer, while it has significantly increased over parts of Saudi Arabia in autumn. As the CRU dataset only covers land areas, analysis based on ERA5 indicates that precipitation has significantly decreased and increased over the Oman Sea in winter and the Persian Gulf in autumn, respectively. Wind speeds between 400 and 100 hPa levels and mean sea level pressure (MSLP) are also analysed during the period 1979–2020. The subtropical jet has risen significantly over eastern parts of Southwest Asia (55–65∘E) in autumn. In winter, the jet has shifted poleward, which resulted in robust decreasing precipitation trends over most parts of Iran and southwestern Pakistan. Over northwestern Iran, however, precipitation has increased in winter in response to a significant decrease in MSLP. In autumn, an equatorward shift of the jet has been accompanied by a significant decrease in MSLP and an increase in precipitation at lower latitudes (20–37∘N) of Southwest Asia.

Kirilenko, Andrei; Dronin, Nikolai

doi: 10.1007/s10584-022-03332-zpmid: N/A

In recent years, Russia has established itself as the leading worldwide supplier of grain and continues to make ambitious plans for raising its grain production in the long term. Within the context of Russian agricultural history, the recent high growth in grain production is exceptional. This growth however is not fully replicated by the “weather-yield” crop models, which project only moderate yield increase in the twenty-first century and fail to predict the most recent record growth in grain yields. The difference between the projected climate-dependent yields and observations is especially high in two of the most important agricultural regions, the Central Black Earth and Northern Caucasus regions while the remaining agricultural zones show good agreement with the regression models. Similar differences were observed in the late 1960s, which we interpret in terms of the rapid changes in agricultural technology during the Union of Soviet Socialist Republic (USSR) agricultural reforms followed by periods of reversal. We also interpret the current period of high differentiation between weather-yield model results and collected yields as evidence of a higher than usual contribution of agricultural reforms in yield improvements, which, however, primarily benefit the large-scale producers located in the most productive areas of Russia.

Busch, K.C.; Ayala Chávez, Regina

doi: 10.1007/s10584-022-03349-4pmid: N/A

It is essential to understand how youth are framing climate change in order to develop effective educational opportunities and targeted communication. For this research, we asked 453 adolescent youth from the Western US to describe climate change, in their own words. Their open-ended responses were qualitatively analyzed to determine the frames employed and the level of psychological distance instantiated. Youth most frequently (n = 270) used frames associated with greater psychological distance: impacts on physical Earth systems, at a global spatial scale, and at a future time. Less frequently, youth (n = 60) used frames associated with nearer psychological distance: impacts on people, plants, and animals; at a local scale; and happening now. Additionally, this research employed correlational analysis to explore the relationship between youth’s psychological distancing to climate change (as represented in their open-ended responses) and their self-reported concern and mitigating behavior. Youth who used a psychologically near discourse reported more concern about climate change than those who used a psychologically distant discourse. However, there was not a statistically significant correlation between psychological distance and behavior. This research may imply the need to communicate climate change in ways to decrease youth’s psychological distancing, connecting climate change’s physical effects to people, social systems, local places, and to the present time. However, more research is required to establish a causal relationship between psychological distance, concern, and behavior.

Karam, Sara; Seidou, Ousmane; Nagabhatla, Nidhi; Perera, Duminda; Tshimanga, Raphael M.

doi: 10.1007/s10584-022-03351-wpmid: N/A

Amadu, Iddrisu; Adongo, Charles Atanga

doi: 10.1007/s10584-022-03333-ypmid: N/A

Empirical studies on the reasons for public support for climate action remain limited in Sub-Saharan Africa (SSA) despite the escalating climate crises and the urgent need to combat it. The current study addressed this evidentiary deficit by examining the influence of climate beliefs, national health security and tourism prioritisation on residents’ support for climate action. We used a dataset from a social survey among 20,258 climate-aware individuals in 30 SSA countries for the analyses. The findings confirm our hypotheses that believers of anthropogenic climate change are more supportive of climate action and increasing national health security decreases residents’ support for climate action. Counterintuitively, a nation’s prioritisation of travel and tourism undermined residents’ support for climate action. While no gendered differences existed in these relationships, sub-regional variations were observed. Our study is one of the most extensive and novel investigations on public support for climate action among underrepresented populations, allowing for cross-regional and gendered comparisons. For desired support, there is the need for clear and persuasive communication on the link between human behaviour and climate change to deal with the controversies and misconceptions on the cause of climate change. Highlighting the co-benefits of a good climate for tourism, health and wellbeing of residents in SSA could also illuminate urgency for climate action.

Knutson, Thomas R.; Sirutis, Joseph J.; Bender, Morris A.; Tuleya, Robert E.; Schenkel, Benjamin A.

doi: 10.1007/s10584-022-03346-7pmid: N/A

In this paper, U.S. landfalling tropical cyclone (TC) activity is projected for the late twenty-first century using a two-step dynamical downscaling framework. A regional atmospheric model, is run for 27 seasons, to generate tropical storm cases. Each storm case is -resimulated (up to 15 days) using the higher-resolution Geophysical Fluid Dynamics Laboratory hurricane model. Thirteen CMIP3 or CMIP5 climate change scenarios are explored. Robustness of projections is assessed using statistical significance tests and comparing changes across models. The proportion of TCs making U.S. landfall increases for the warming scenarios, due, in part, to an increases in the percentage of TC genesis near the U.S. coast and a change in climatological steering flows favoring more U.S. landfall events. The increases in U.S. landfall proportion leads to an increase in U.S. landfalling category 4–5 hurricane frequency, averaging about + 400% across the models; 10 of 13 models/ensembles project an increase (which is statistically significant in three of 13 models). We have only tentative confidence in this latter increase, which occurs despite a robust decrease in Atlantic basin category 1–5 hurricane frequency, no robust change in Atlantic basin category 4–5 and U.S. landfalling category 1–5 hurricane frequency, and no robust change in U.S. landfalling hurricane intensities. Rainfall rates, averaged within a 100-km radius of the storms, are projected to increase by about 18% for U.S. landfalling TCs. Important caveats to the study include low correlation (skill) for interannual variability of modeled vs. observed U.S. TC landfall frequency and model bias of excessive TC genesis near and east of the U.S. east coast in present-day simulations.

Bruine de Bruin, Wändi; Dugan, Andrew

doi: 10.1007/s10584-022-03353-8pmid: N/A

Global climate action will likely be motivated by public concerns about climate change and severe weather, to the extent that they are different. Public perception researchers have been debating whether or not people conflate climate and weather. If climate change concerns and severe weather concerns are different, then they should be formed in different ways. Here, we compare how climate change concerns and severe weather concerns around the world are correlated with key predictors of risk concerns: (1) higher education, which facilitates risk understanding, and (2) experiences and perceptions of severe weather, which increase feelings of concern. We analyze data from the 2019 Lloyd’s Register Foundation World Risk Poll, which was conducted in 142 countries. We find that people who have a college or high-school degree (vs. at most completed elementary school) are more concerned about climate change, but education is unrelated to severe weather concerns. People with experiences and perceptions of severe weather events are more likely to report climate change concerns and severe weather concerns, but the relationships with severe weather concerns are stronger. Thus, climate change concerns and severe weather concerns seem to be formed differently. Findings hold when controlling for household income, other individual characteristics, and country characteristics. They also hold in separate analyses for each World Bank country-income category and continent. These findings suggest that climate change communications should aim to be understandable to audiences at all educational levels and facilitate connections to personal experiences and perceptions of severe weather to climate change.

Noorazar, Hossein; Kalcsits, Lee; Jones, Vincent P.; Jones, Matthew S.; Rajagopalan, Kirti

doi: 10.1007/s10584-022-03339-6pmid: N/A

Winter chill accumulation is critical for the productivity and profitability of perennial tree fruit systems. Several studies have quantified the impacts of global warming on chill accumulation in the warmer production regions of the world, where insufficient chill events occur and their frequency is increasing. In contrast, we focus on a region with relatively cold winters–the Pacific Northwest United States (PNW)–where insufficient chill events are currently absent, and quantify the potential for introduction of these risks under climate change. Our results show spatial variation within the PNW, with chill accumulation projected to increase in some areas but decrease in others. There was also spatiotemporal variation in the driving factors of changes to chill accumulation. Even with decreases in chill accumulation, there are likely minimal issues with insufficient chill accumulation. However, delayed chill accumulation in combination with advances in the onset of heat accumulation can potentially shift the region from one where spring phenology is primarily forcing-driven to one where interaction between chilling and forcing processes become important. These interactions might create production risks for varieties with high chill requirements, post mid-21st century under high emissions scenarios. Future work should focus on understanding, modeling, and projecting responses across these overlapping chilling and forcing processes. Additionally, given significant spatial differences across a relatively small geographic range, it is also critical to understand and model these dynamics at a local landscape resolution for regions such as the PNW.