Effects Of Climate Trends Research Articles

Effects of climate trends and variability on tree health responses in the Black Sea and Mediterranean forests of Türkiye

To adapt forest ecosystems and forest management to climate change, it is essential to know which forest regions and which tree species are resilient to climate variability and which ones are possibly affected most by past and anticipated future changes. In this contribution, for the main forest regions of Türkiye and six tree species, recent climate variability and trends were quantified and statistically correlated to record tree defoliation and vitality. Climate variables considered are maximum temperature (Tmax), minimum temperature (Tmin), mean temperature (Tmean), and total precipitation (Prcp), which are compared to forest health responses recorded as part of the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) on 277 plots across forests along the Black Sea and Mediterranean regions. In addition, long-term data on satellite measurements of the normalized difference vegetation index (NDVI) were extracted for the same 277 plots for the period 2008–2020. Firstly, 30 years (1991–2020) of reanalysis of climate variables from ECMWF were extracted for all plots; secondly, individual correlations and cross-correlations of climate variables and tree health and vitality were computed for the period 2008–2020 (significance level of 95%) for the four most dominant species from the Black Sea forests (F. orientalis, Q. cerris, P. sylvestris, P. orientalis) and two species from Mediterranean forests (P. brutia and C. libani). Temperature showed a stronger effect on most species than precipitation. Finally, time-lagged correlations were analyzed for seven-time lags (significance level of 95%) to evaluate legacy effect. The analysis revealed that different tree species from the two regions show different responses to climate variables. Species in the Mediterranean region are more resistant to droughts and climatic variations. Legacy effects of defoliation and NDVI have lasted for at least 2 years.

Insights into the Drivers and Spatiotemporal Trends of Extreme Mediterranean Wildfires with Statistical Deep Learning

Abstract Extreme wildfires continue to be a significant cause of human death and biodiversity destruction within countries that encompass the Mediterranean Basin. Recent worrying trends in wildfire activity (i.e., occurrence and spread) suggest that wildfires are likely to be highly impacted by climate change. To facilitate appropriate risk mitigation, it is imperative to identify the main drivers of extreme wildfires and assess their spatiotemporal trends, with a view to understanding the impacts of the changing climate on fire activity. To this end, we analyze the monthly burnt area due to wildfires over a region encompassing most of Europe and the Mediterranean Basin from 2001 to 2020 and identify high fire activity during this period in eastern Europe, Algeria, Italy, and Portugal. We build an extreme quantile regression model with a high-dimensional predictor set describing meteorological conditions, land-cover usage, and orography, for the domain. To model the complex relationships between the predictor variables and wildfires, we make use of a hybrid statistical deep learning framework that allows us to disentangle the effects of vapor pressure deficit (VPD), air temperature, and drought on wildfire activity. Our results highlight that while VPD, air temperature, and drought significantly affect wildfire occurrence, only VPD affects wildfire spread. Furthermore, to gain insights into the effect of climate trends on wildfires in the near future, we focus on the extreme wildfires in August 2001 and perturb VPD and temperature according to their observed trends. We find that, on average over Europe, trends in temperature (median over Europe: +0.04 K yr−1) lead to a relative increase of 17.1% and 1.6% in the expected frequency and severity, respectively, of wildfires in August 2001; similar analyses using VPD (median over Europe: +4.82 Pa yr−1) give respective increases of 1.2% and 3.6%. Our analysis finds evidence suggesting that global warming can lead to spatially nonuniform changes in wildfire activity.

The effects of climatic trends on agriculture in Western Uzbekistan

The effects of climatic trends on agriculture in Western Uzbekistan

A More Comprehensive Climate Vulnerability Assessment Framework for Fisheries Social-Ecological Systems

Understanding and anticipating the effects of climate change on fisheries social-ecological systems (FSESs) is central to proactive fisheries management in a changing global climate. With fisheries management increasingly striving to consider interactions and feedbacks among people, targeted species, and the broader ecological and human communities, fisheries managers and participants need tools to help them assess these complex systems. We developed a new climate vulnerability assessment framework for analyzing the impacts of a climate-induced trend or event on a FSES. The framework divides the FSES into four interrelated and interacting domains: Ecological Community, Fished Species, Fishery, and Human Community. The framework provides a systematic approach to account for indirect as well as direct effects, links among subsystems, and multiple climate change-induced stressors. We demonstrate the framework’s utility by applying it to three case studies: the effects of a marine heatwave on the Dungeness crab FSES, the effects of a marine heatwave on the red sea urchin FSES, and the effects of long-term climate trends on North Pacific albacore. We found that the effects of a climatic trend or event on a FSES are often indirect and can trigger diverse and important feedbacks. These examples also showed that the climatic trend or event may cause changes in the temporal and spatial distribution of fishing effort and fished species that have a more significant impact on the FSES than changes to species abundance per se. Unlike other climate vulnerability assessment frameworks and applications, ours is designed to enable consideration of the range of feedbacks within and among both the ecological and human communities. As such, it is a valuable tool to guide the holistic examination and assessment of potential impacts to FSESs.

On the effect of climate trends in coastal density on deep water renewal frequency in sill fjords—A statistical approach

The basin water of a sill fjord is renewed intermittently, when the density of the water at sill level in the ocean outside the fjord is high enough for it to sink down to the bottom of the fjord. How often the basin water is renewed, the renewal frequency, depends on how fast diffusion and mixing cause the density in the basin to decrease and on the variability of the density in the ambient ocean. Here, we suggest a statistical approach to investigate how a trend – e.g. imposed by global warming – in the ambient ocean density will affect the renewal frequency of a sill fjord. Negative ambient trends that are large compared to the rate at which density decreases the fjord will have large impact on the renewal frequency. It is shown that the observed negative trend in the annual maximum density at a hydrographical station near the Norwegian fjord Masfjorden, is very likely to have reduced the renewal frequency and increased the length of the stagnation period compared to pre-trend conditions. Negative trends in the annual maximum density since 1990 are observed at six out of eight longterm hydrographical stations along the Atlantic Norwegian coast, suggesting that the deep water renewal frequency in many Norwegian fjords has been reduced during the last 30 years.

Effects of climate trends and drought events on urban tree growth in Santiago de Chile

Urban trees and the services they provide (e.g., evapotranspirational cooling, shading, recreation, carbon storage, air pollution filtering) can have major effects on the microclimate of a city, although the growth conditions are often inadequate to ensure tree vitality and growth, negatively affecting their beneficial effects. In a worldwide dendrochronological study on ten urban tree species in four climatic zones, the growth and impacts of common urban tree species were assessed. This paper focuses on the results for Robinia pseudoacacia L. in the Mediterranean climate city of Santiago de Chile, highlighting the faster growth of the studied black locust trees since 1960 than its growth in the years before 1960. Furthermore, black locust displayed the best growth when situated closer to the city center than the city periphery and when in the northern and western parts of Santiago de Chile. The species characteristics of black locust also revealed an immediate negative growth reaction to drought events, followed by a rapid recovery, which was similarly influenced by the direction from and distance to the city center of the growing site. The results underline the overall worldwide findings on urban tree growth that indicate that a city climate with an extended growing season and increased temperatures can lead to improved growth of urban trees in the Mediterranean climatic zone. However, with increased growth, more rapid ageing and tree death might follow, leading to increased costs for new plantings and tree management.

Effects of climate trends and variability on wheat yield variability in eastern Australia

Effects of climate trends and variability on wheat yield variability in eastern Australia

Investigating the effects of long-term hydro-climatic trends on Midwest ice jam events

Ice freezeup, breakup and jamming events on northern rivers can cause extensive flooding, damage infrastructure, impede navigation, and impact stream stability and the environment. Under a changing climate the ice regime will change as well, meaning increased risk and uncertainty for affected areas. The layman's perception is that climate change is causing warming that is reducing the length of the ice season, so there will be less ice and less damaging impacts from river ice. The concept of ‘less ice’ is supported by studies showing shorter ice-affected seasons. However several studies have found that in temperate regions, the effects of climate trends – increasing temperatures and precipitation – may actually exacerbate problems. In recent years, communities in the Midwest U.S. have experienced long duration ice jam events that have resulted in flooding, damages and evacuations. This study presents a first step in identifying trends in damaging ice events in the Midwest. We analyzed the ice regime of three rivers in the region to determine if trends in the hydro-climatic data support the increasing number of damaging freezeup jams observed in recent years, but no regional pattern in trends related to breakup jams were found. We found statistically increasing trends in discharge and precipitation, with no corresponding increase in winter period temperature, which provide evidence for the change in the ice regime for this region. A hindcasting analysis was used to construct a more complete record of historical ice events. This analysis revealed a statistically significant increase in frequency of freezeup jams for most sites and no regional trend in the frequency of midwinter or spring breakup jams. Some increase in the freezeup jam strength was indicated by an increasing trend in the number of freezing degree days (FDD) in the freezeup jam formation period. Communities need to shift their emergency preparedness for river ice problems from the existing focus on relatively regular, short-acting spring breakups. Future emergency management plans need to prepare to respond to the risk and impact of freezeup jams that, according to this analysis, are increasing in frequency and strength while occurring with less predictability and having longer term effects if they freeze in place.

Marine mammal and seabird summer distribution and abundance in the fjords of northeast Cumberland Sound of Baffin Island, Nunavut, Canada

Critical baseline population knowledge is required to properly assess the status of marine mammal and bird populations in the Canadian Arctic and the effects of climate trends on them. To address this need for one significant Arctic region, a boat-based marine mammal and seabird transect survey was conducted in Cumberland Sound fjords during summer 2008. During 173 km effort (20 h), 959 birds were recorded representing at least nine species which were dominated by Common Eiders (Somateria mollissima borealis), Iceland or Glaucous Gulls (Larus glaucoides or Larus hyperboreus), and Black Guillemots (Cepphus grylle), in addition to less common birds including Red-throated and Common Loons (Gavia stellata and Gavia immer), Northern Fulmars (Fulmarus glacialis), and Great or Lesser Black-backed Gulls (Larus marinus or Larus fuscus). Of these, 480 birds were observed on the water in one event consisting of eiders and gulls which may have biased encounter rates. Of 101 marine mammal sightings, four species were represented: 73 harp seals (Pagophilus groenlandicus), 13 beluga whales (Delphinapterus leucas), nine bowhead whales (Balaena mysticetus), five ringed seals (Pusa hispida), and one unidentified pinniped. A pod of four killer whales (Orcinus orca) was observed off-effort in Pangnirtung Fjord during the survey period. This pilot study provided the first estimates of relative abundance for marine mammals and seabirds in the study area to aid in developing future surveys.

Increase in summer European ozone amounts due to climate change

The local and regional distribution of pollutants is significantly influenced by weather patterns and variability along with the spatial patterns of emissions. Therefore, climatic changes which affect local meteorological conditions can alter air quality. We use the regional air quality model CHIMERE driven by meteorological fields from regional climate change simulations to investigate changes in summer ozone mixing ratios over Europe under increased greenhouse gas (GHG) forcing. Using three 30-year simulation periods, we find that daily peak ozone amounts as well as average ozone concentrations substantially increase during summer in future climate conditions. This is mostly due to higher temperatures and reduced cloudiness and precipitation over Europe and it leads to a higher number of ozone events exceeding information and warning thresholds. Our results show a pronounced regional variability, with the largest effects of climate change on ozone concentrations occurring over England, Belgium, Germany and France. The temperature-driven increase in biogenic emissions appears to enhance the ozone production and isoprene was identified as the most important chemical factor in the ozone sensitivity. We also find that summer ozone levels in future climate projections are similar to those found during the exceptionally warm and dry European summer of 2003. Our simulations suggest that in future climate conditions summer ozone might pose a much more serious threat to human health, agriculture and natural ecosystems in Europe, so that the effects of climate trends on pollutant amounts should be considered in future emission control measures.

Water Scarcity Under Scenarios for Global Climate Change and Regional Development in Semiarid Northeastern Brazil

The state of Ceará, located in semiarid northeastern Brazil, suffers under irregularly recurring droughts that go along with water scarcity. Structural policies to control and reduce water scarcity, as water supply and demand management, should be seen as long-term planning, and thus must consider climate change and regional development. To this end, the present research proposes a model-based global change scenario. Water stress is assessed for 184 municipalities in Ceará between 2001 and 2025. For this purpose, four global change scenarios are developed, considering both global climate change and the effects of development policies. Climatic, hydrological, and water use models are applied and a proposed index computed for identification of long-term water stress. Application of the methodology in the focus area shows that, if no effective intervention measures are taken, up to almost 60 percent of the municipalities of the state may suffer under long-term water scarcity by 2025. On average, municipalities in the state of Ceará have a water shortage probability for the next 25 years ranging from 9 percent to 20 percent annually, depending on the scenario. The 10 percent most stressed municipalities have a probability of over 80 percent annually of facing water scarcity in the scenario period (25 years). Results also show that a decentralized development policy can compensate for the possible severe effects of climatic trends on future water availability over the scenario period.

Increased Australian wheat yield due to recent climate trends

The possibility that future climate change may affect agriculture has attracted considerable attention1,2. As a step towards evaluating such influences, the effect of climate trends over the past few decades3 needs to be assessed. Here I estimate the contribution of climate trends in Australia4,5 to the substantial increase in Australian wheat yields since 1952. Non-climatic influences— such as new cultivars and changes in crop management practices—are removed by detrending the wheat yield and climate variables and using the residuals to calculate quantitative relationships between variations in climate and yield. Climate trends appear to be responsible for 30–50% of the observed increase in wheat yields, with increases in minimum temperatures being the dominant influence. This approach should be applicable in other regions for which sufficient data exist.

Colourful migratory birds: evidence for a mechanism other than parasite resistance for the maintenance of ‘good genes’ sexual selection

The evolution of adaptive mate choice and sexual selection for traits indicating the genetic quality of prospective mates depends upon processes maintaining heritable variation for these traits. A new mechanism for the maintenance of \`good genes' is proposed: in migratory birds, variation in the genes influencing migration is maintained in the population by fluctuating directional selection caused by the effects of climatic trends on the suitability of overwintering environments. The suitability of a surviving migrant's overwintering area affects its spring condition and is reflected in its breeding plumage; environmentally influenced phenotypic condition is thereby associated with migratory genes and condition-dependent traits available for sexual selection. This hypothesis predicts that migratory birds should be more colourful than residents, whereas, because in migrants the correlation and hence coevolution between parasitism and coloration is lower than in residents, the Hamilton-Zuk hypothesis of parasite resistance \`good genes' predicts the opposite. Comparison of 37 phylogenetically independent intrageneric pairs of species showed migrants to have significantly more contrasting and colourful plumage and bare parts than residents: the `good migrations' mechanism rather than the Hamilton-Zuk hypothesis is thus supported for migrant bird coloration.