Evaluating climate change at the Croatian Adriatic from observations and regional climate models’ simulations

The 2m temperature (T2m) and precipitation from five regional climate models (RCMs), which participated in the ENSEMBLES project and were integrated at a 25-km horizontal resolution, are compared with observed climatological data from 13 stations located in the Croatian coastal zone. The twentieth century climate was simulated by forcing RCMs with identical boundary conditions from the ERA-40 reanalysis and the ECHAM5/MPI-OM global climate model (GCM); climate change in the twenty-first century is based on the A1B scenario and assessed from the GCM-forced RCMs’ integrations. When forced by ERA-40, most RCMs exhibit cold bias in winter which contributes to an overestimation of the T2m annual cycle amplitude and the errors in interannual variability are in all RCMs smaller than those in the climatological mean. All models underestimate observed warming trends in the period 1951–2010. The largest precipitation biases coincide with locations/seasons with small observed amounts but large precipitation amounts near high orography are relatively well reproduced. When forced by the same GCM all RCMs exhibit a warming in the cold half-year and a cooling (or weak warming) in the warm period, implying a strong impact of GCM boundary forcing. The future eastern Adriatic climate is characterised by a warming, up to +5 °C towards the end of the twenty-first century; for precipitation, no clear signal is evident in the first half of the twenty-first century, but a reduction in precipitation during summer prevails in the second half. It is argued that land-sea contrast and complex coastal configuration of the Croatian coast, i.e. multitude of island and well indented coastline, have a major impact on small-scale variability. Orography plays important role only at small number of coastal locations. We hypothesise that the parameterisations related to land surface processes and soil hydrology have relatively stronger impact on variability than orography at those locations that include a relatively large fraction of land (most coastal stations), but affecting less strongly locations at the Adriatic islands.     

The new national climate change documents of Mexico: what do the regional climate change scenarios represent?

This paper presents a review of the methodology applied for generating the regional climate change scenarios utilized in important National Documents of Mexico, such as the Fourth National Communication to the United Nations Framework Convention on Climate Change, the Fourth National Report to the Convention on Biological Diversity and The Economics of Climate Change in Mexico. It is shown that these regional climate change scenarios, which are one of the main inputs to support the assessments presented in these documents, are an example of the erroneous use of statistical downscaling techniques. The arguments presented here imply that the work based on such scenarios should be revised and therefore, these documents are inadequate for supporting national decision- making.     

Does the model regional bias affect the projected regional climate change? An analysis of global model projections

An analysis is presented of the dependence of the regional temperature and precipitation change signal on systematic regional biases in global climate change projections. The CMIP3 multi-model ensemble is analyzed over 26 land regions and for the A1B greenhouse gas emission scenario. For temperature, the model regional bias has a negligible effect on the projected regional change. For precipitation, a significant correlation between change and bias is found in about 30% of the seasonal/regional cases analyzed, covering a wide range of different climate regimes. For these cases, a performance-based selection of models in producing climate change scenarios can affect the resulting change estimate, and it is noted that a minimum of four to five models is needed to obtain robust precipitation change estimates. In a number of cases, models with largely different precipitation biases can still produce changes of consistent sign. Overall, it is assessed that in the present generation of models the regional bias does not appear to be a dominant factor in determining the simulated regional change in the majority of cases.     

Historicizing climate change—engaging new approaches to climate and history

This introduction to a special issue of Climatic Change argues that it is timely and welcome to intensify historical research into climate change and climate as factors of history. This is also already an ongoing trend in many disciplines. The article identifies two main strands in historical work on climate change, both multi-disciplinary: one that looks for it as a driver of historical change in human societies, the other that analyzes the intellectual and scientific roots of the climate system and its changes. In presenting the five papers in this special issue the introduction argues that it is becoming increasingly important to also situate “historicizing climate change” within the history of thought and practice in wider fields, as a matter of intellectual, political, and social history and theory. The five papers all serve as examples of intellectual, political, and social responses to climate-related phenomena and their consequences (ones that have manifested themselves relatively recently and are predominantly attributable to anthropogenic climate change). The historicizing work that these papers perform lies in the analysis of issues that are rising in societies related to climate change in its modern anthropogenic version. The history here is not so much about past climates, although climate change itself is always directly or indirectly present in the story, but rather about history as the social space where encounters take place and where new conditions for humans and societies and their companion species and their life worlds in natures and environments are unfolding and negotiated. With climate change as a growing phenomenon historicizing climate change in this version will become increasingly relevant.     

Hidden climate change – urban meteorology and the scales of real weather

This paper discusses the scale at which the weather is experienced and modified by human activities in urban environment. The climates of built-up areas differ from their non-urban counterparts in many aspect: wind-flows, radiation, humidity, precipitation and air quality all change in the presence of human settlement, transforming each city into a singularity within its regional weather system. Yet this pervasive category of anthropogenic climate change has always tended to be hidden and difficult to discern. The paper first describes the sequence of discovery of the urban heat island since the early nineteenth century, and the emergence and consolidation of a scientific field devoted to the climatology of cities. This is followed by a discussion of various attempts to apply knowledge of climatic factors to the design and management of settlement. We find that real-world application of urban climatology has met with limited success. However, the conclusion suggests that global climate change gives a new visibility and practical relevance to urban-scale climate science.     

Who feels the impacts of climate change?

Feeling affected by climate change related disasters has the potential to mobilize belief in climate change, concern about the issue, and support for mitigation policies – even when accounting for the effects of physically living through a disaster. In this study we use a two-wave survey design where respondents in the United States were interviewed before and after Hurricane Florence to better understand who feels affected by such disasters. First, we find that being worried about climate change increases the feeling of being affected by the hurricane among those who regularly discuss climate change. Second, we find that those who are high in perspective taking are more likely to feel affected. However, those who are high in empathic concern, but feel obligated to help victims of disasters, are less likely to feel affected. This suggests that hurricanes may cause a collapse of compassion, where those who are especially sensitive to the suffering of others down-regulate their emotional response to costly disasters.     

Institutions in conflict? the climate change flexibility mechanisms and the multinational trading system

In an attempt to combat climate change on a global scale, the Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) was adopted in conjunction with a wide range of policies both at national and international level. In particular, flexibility mechanisms-emissions trading system, joint implementation (JI) and clean development mechanism (CDM)-were incorporated in the Protocol to fulfil the commitment of the Parties by utilising a market system. Under the flexibility mechanisms, an artificial market is created in which the emission allowances or emission reduction units are traded. Not surprisingly, such measures might result in significant impacts on the trade of both goods and services, presumably creating the most complex and dynamic interaction with the Multilateral Trading System (MTS) which is overseen by the World Trade Organisation (WTO). If the implementation of flexibility mechanisms is identified as inconsistent with the requirements of the MTS, enforcement of such policies may prove difficult due to constraints imposed by GATT/WTO provisions.The purpose of this article is to scrutinise potential incompatibility between the implementation of flexibility mechanisms and GATT/WTO provisions. The rules governing the implementation of flexibility mechanisms have yet to be decided due to the divergent views of States regarding the design of the mechanisms. Thus, the analysis of the interaction will be undertaken based on hypothetical scenarios of each mechanism to account for all possible consequences of their implementation. Such an analysis will facilitate detection of any potential conflicts between the implementation of flexibility mechanisms and the trade regimes in advance, thus encompassing the potential incompatibility in designing the mechanisms and helping achieve increasingly effective implementation of flexibility mechanisms.     

Global climate change and variability and its influence on Alpine climate — concepts and observations

Summary The paper discusses annual to decadal climate variability and change in the European Alps by utilizing the procedure of synoptic downscaling, i.e. it investigates the influence of global to continental scale synoptic structures and processes on the regional climate of the Alps. The European Alps lie to the southeast and under the right exit zone of the southwest-northeast oriented axis of the polar front jet over the North Atlantic ocean, in a transition zone between the Azores high and Icelandic low, between oceanic and continental and between Mediterranean and North Atlantic climates. Together with complex topographically induced phenomena like lee cyclogenesis, orographic precipitation, strong downslope winds and thermotopographical circulation systems, this transitional position makes climate studies in the Alps even more interesting. Only a minor correlation can be observed between global climate variability and Alpine climate. In contrast, the Alpine climate is strongly related to processes over the North Atlantic ocean and its sea ice system (e.g. it has a high correlation with the North Atlantic Oscillation and the dynamics and position of the Icelandic low), an area with a rather low climate prediction potential.Since the early 1970's (or just after the Great Salinity Anomaly in the North Atlantic Ocean) the intensification of the wintertime westerly jet over the North Atlantic area led to a noticeable northwest-southeast mass transport in the exit area of the jet over Central Europe, leading to pressure and temperature rises and an increase in the amount of precipitation. There is a question over whether this phenomenon is a consequence of natural climate variability or the beginning of an anthropogenic climate change.With 16 Figures     

Meeting the EU 2°C climate target: global and regional emission implications

Abstract

This article presents a set of multi-gas emission pathways for different CO₂-equivalent concentration stabilization levels, i.e. 400, 450, 500 and 550 ppm CO₂-equivalent, along with an analysis of their global and regional reduction implications and implied probability of achieving the EU climate target of 2°C. For achieving the 2°C target with a probability of more than 60%, greenhouse gas concentrations need to be stabilized at 450 ppm CO₂-equivalent or below, if the 90% uncertainty range for climate sensitivity is believed to be 1.5–4.5°C. A stabilization at 450 ppm CO₂-equivalent or below (400 ppm) requires global emissions to peak around 2015, followed by substantial overall reductions of as much as 25% (45% for 400 ppm) compared to 1990 levels in 2050. In 2020, Annex I emissions need to be approximately 15% (30%) below 1990 levels, and non-Annex I emissions also need to be reduced by 15–20% compared to their baseline emissions. A further delay in peaking of global emissions by 10 years doubles maximum reduction rates to about 5% per year, and very probably leads to high costs. In order to keep the option open of stabilizing at 400 and 450 ppm CO₂-equivalent, the USA and major advanced non-Annex I countries will have to participate in the reductions within the next 10–15 years.     

Creating regional climate change scenarios over southern South America for the 2020’s and 2050’s using the pattern scaling technique: validity and limitations

Dynamical downscaling of global climate simulations is the most adequate tool to generate regional projections of climate change. This technique involves at least a present climate simulation and a simulation of a future scenario, usually at the end of the twenty first century. However, regional projections for a variety of scenarios and periods, the 2020s or the 2050s, are often required by the impact community. The pattern scaling technique is used to estimate information on climate change for periods and scenarios not simulated by the regional model. We based our study on regional simulations performed over southern South America for present climate conditions and two emission scenarios at the end of the twenty first century. We used the pattern scaling technique to estimate mean seasonal changes of temperature and precipitation for the 2020s and the 2050s. The validity of the scalability assumptions underlying the pattern scaling technique for estimating near future regional climate change scenarios over southern South America is assessed. The results show that the pattern scaling works well for estimating mean temperature changes for which the regional changes are linearly related to the global mean temperature changes. For precipitation changes, the validity of the scalability assumption is weaker. The errors of estimating precipitation changes are comparable to those inherent to the regional model and to the projected changes themselves.     

Radial growth change of temperate tree species in response to altered regional climate and air quality in the period 1901–2008

Both increasing and decreasing 20th century growth trends have been reported in forests throughout Europe, but only for few species and areas suitable modelling techniques have been used to distinguish individual tree growth (operating on a local scale) from growth change due to exogenous factors (operating on a broad geographical scale). This study relates for the first time observed growth changes, in terms of basal area increment (BAI) of dominant trees of pedunculate oak, common beech and Scots pine, in north-west European temperate lowland forests (Flanders) to climate, atmospheric CO₂ and tropospheric O₃ concentrations, N deposition, site quality and forest structure for more than a century (the period 1901?C2008), applying mixed models. Growth change during the 20th century is observed for oak (increasing growth) and beech (increasing growth until the 1960s, growth decline afterwards), but not for pine. It was possible to relate growth change of oak and beech to climate time series and N deposition trends. Adding time series for CO₂ and O₃ concentration did not significantly improve model results. For oak and beech a switch from positive to negative growth response with increasing nitrogen deposition throughout time is observed. Growth increase for oak is mainly determined by the interaction between growing season temperature and soil water recharge. It is reasonable to assume that the observed growth trend for oak will continue for as long as early season water availability is not compromised. The decreasing trend in summer relative air humidity observed since the 1960s in the study area can be a main cause of recent beech BAI decrease. A further growth decline of beech can be expected, independent of site quality.     

Unstoppable climate change? The influence of fatalistic beliefs about climate change on behavioural change and willingness to pay cross-nationally

Although climate change is an urgent problem, behavioural and policy responses have not yet been sufficient to either reduce the volume of greenhouse gas emissions or adapt to a disrupted climate system. Significant efforts have been made to raise public awareness of the dangers posed by climate change. One reason why these efforts might not be sufficient is rooted in people’s need to feel efficacy to solve complex problems; the belief that climate change is unstoppable might thwart action even among the concerned. This paper tests for the effect of fatalistic beliefs on behavioural change and willingness to pay to address climate change using two cross-national surveys representing over 50,000 people in 48 nations.

Key policy insights

• The perception that climate change poses a risk or danger increases the likelihood of behavioural change and willingness to pay to address climate change.

• The belief that climate change is unstoppable reduces the behavioural and policy response to climate change and moderates risk perception.

• Communicators and policy leaders should carefully frame climate change as a difficult, yet solvable, problem to circumvent fatalistic beliefs.

     

Mean, interannual variability and trends in a regional climate change experiment over Europe. I. Present-day climate (1961–1990)

We present an analysis of a multidecadal simulation of present-day climate (1961–1990) over Europe with the regional climate model RegCM nested within the global atmospheric model HadAMH. Climatic means, interannual variability and trends are examined, with focus on surface air temperature and precipitation. The RegCM driven by HadAMH fields is able to reproduce the basic features of the observed mean surface climate over Europe, its seasonal evolution and the regional detail due to topographic forcing. Surface air temperature biases are mostly less than 1–2 °C and precipitation biases mostly within 10–20%. The RegCM has more intense vertical transport of temperature and water vapor than HadAMH, which results in lower surface air temperatures and greater precipitation than found in the HadAMH simulation. In some cases this is in the direction of greater agreement with observations, while in others it is in the opposite direction. The simulation shows a tendency to overestimate interannual variability of temperature and precipitation compared to observations, particularly during summer and over the Mediterranean regions. It is shown that in DJF, MAM and SON the RegCM interannual variability is primarily determined by the boundary forcing from HadAMH, while in JJA the internal model physics and resolution effects dominate over many subregions of the domain, and the RegCM has higher interannual variability than HadAMH. The precipitation trends simulated by the nested modeling system for the period 1961–1990 capture some features of the observed trends, in particular the cold season drying over the Mediterranean regions. Ensembles of simulations are, however, needed for a more robust assessment of the models capability to simulate climatic trends. Overall, this simulation is of good quality compared with previous nested RegCM experiments and will constitute the basis for the generation of climate change scenarios over the European region to be reported in future work.     

Are homeowners willing to adapt to and mitigate the effects of climate change?

The need to adapt to climate change impacts, whilst simultaneously limiting greenhouse gas emissions, requires that the government’s efforts are joined by public action. In England and Wales, housing contributes significantly to the emissions and many properties are at risk of flooding. This paper investigates the preparedness of homeowners in England and Wales to make changes to their homes in response to the predicted effects of climate change. A telephone survey of 961 homeowners investigated their interest in purchasing mitigation and adaptation improvements against their concern about climate change, awareness of flood risk and attribution of responsibility for action. Whilst the majority of homes had some energy-saving improvements, few were found to have property-level flood protection. The high levels of awareness about climate change and flooding were coupled with the perception of risks as low. Whilst some respondents accepted personal responsibility for action, most believed that the authorities were responsible for flood protection, and would not pay the costs required to make their home more energy-efficient and better prepared for the eventuality of floods. The results suggest that there is scope for further improvement of energy-saving measures, and that the levels of adoption of flood-protection measures are very low. Multi-faceted strategies, including more effective communication of risks and responsibilities, incentives, and material support for the poorest, will need to be developed to overcome the current reluctance by homeowners to invest in flood-protection measures and further energy conservation solutions in the future.     

Bimodality and regime behavior in atmosphere–ocean interactions during the recent climate change

Maximum covariance analysis (MCA) and isometric feature mapping (Isomap) are applied to investigate the spatio-temporal atmosphere–ocean interactions otherwise hidden in observational data for the period of 1979–2010. Despite an established long-term surface warming trend for the whole northern hemisphere, sea surface temperatures (SST) in the East Pacific have remained relatively constant for the period of 2001–2010. Our analysis reveals that SST anomaly probability density function of the leading two Isomap components is bimodal. We conclude that Isomap shows the existence of two distinct regimes in surface ocean temperature, resembling the break and active phases of rainfall over equatorial land areas. These regimes occurred within two separated time windows during the past three decades. Strengthening of trade winds over Pacific was coincident with the cold phase of east equatorial Pacific. This pattern was reversed during the warm phase of east equatorial Pacific. The El Niño event of 1997/1998 happened within the transition mode between these two regimes and may be a trigger for the SST changes in the Pacific. Furthermore, we suggest that Isomap, compared with MCA, provides more information about the behavior and predictability of the inter-seasonal atmosphere–ocean interactions.     

“Grand Paris”: regional landscape change to adapt city to climate warming

“Grand Paris” is a study carried out by ten teams of researchers and city planners in the aim of putting forward general guidelines for Paris urban area’s evolution by 2030. All the teams suggest making the area “greener” in some way, to combat climate warming by CO₂ sequestration. Our team also shows that extending the nearby forests by 30 %, favouring short farm-to-consumer circuits and using lighter coloured building materials will decrease the urban heat island, reducing the mortality during heat waves as well as the need for air-conditioning. These results lead us to reverse the way of thinking urban planning: the geographic and natural aspects should replace the urban infrastructure as a driver for planning urban development. This new strategy allows city changes on quite a large scale, that will have a favourable impact in terms of economics, leisure activities, greenhouse gas emissions and the local microclimate.     

Enteric fermentation and ruminant eructation: the role (and control?) of methane in the climate change debate

Anthropogenic processes are responsible for between 55% and 70% of the estimated 600 Tg of methane that is released annually into the atmosphere, with enteric fermentation a major contributor to emissions in a number of countries. This paper therefore reviews current levels of CH₄ discharges by both animal type and country, and shows how the growth or decline in national herds over the last 20 years has significantly altered the global composition of enteric emissions. As developing countries are now responsible for almost three-quarters of such emissions, this has important implications in terms of mitigation strategies—particularly as such countries are presently outside the remit of the Kyoto Protocol.