• Energy Research

The well-documented energy balance dynamics within forest ecosystems are poorly implemented in studies of the biophysical effects of forests. This results in limitations to the accurate quantification of forest cooling/warming on local air temperature. Taking into consideration the forest air space, this study proposes a three-layered (canopy, forest air space and soil [CAS]) land surface energy balance model to simulate air temperature within forest spaces (Taf) and subsequently to evaluate its biophysical effects on forest cooling/warming, i.e., the air temperature gradient (∆Ta) between the Taf and air temperature of open spaces (Tao) (∆Ta = Taf - Tao). We test the model using field data for 23 sites across 10 cities worldwide; the model shows satisfactory performance with the test data. High-latitude forests show greater seasonal dynamics of ∆Ta, generating considerable cooling of local air temperatures in warm seasons but minimal cooling or even warming effects during cool seasons, while low-latitude tropical forests always exert cooling effects with less interannual variability. The interannual dynamics of ∆Ta are significantly related to the seasonality of solar geometry and canopy leaf phenology. The differences between forest canopy temperature (Tc) and Tao, which are the two most important terms attributed by the CAS model in impacting Taf, explain a large part of forest cooling and warming (May-July: R2 = 0.35; November-January: R2 = 0.51). The novel CAS model provides a feasible way to represent the energy balance within forest ecosystems and to assess its impacts on local air temperatures globally.

Cultural heritage sites and landscapes are intuitively connected in urban systems. Based on available databases of cultural landmarks, we selected three pairs of cities that are currently dominated by three contrasting religions (Catholic, Buddhist and emerging culture) to compare the long-term changes in cultural landmarks, to quantify their spatial distribution in the current landscape, and to examine the potential influences these landmarks have on landscapes. The landmark database and landscapes were constructed from archived maps, satellite imagery and the UNESCO heritage sites for Barcelona, Bari, Beijing, Vientiane, Shenzhen, and Ulaanbaatar. Roads in Asian cities are mostly constructed in alignment with the four cardinal directions, forming a checkerboard-type landscape, whereas Bari and Barcelona in Europe have examples of roads radiating from major cultural landmarks. We found clear differences in the number of landmarks and surrounding landscape in these cities, supporting our hypothesis that current urban landscapes have been influenced similarly by cultural landmarks, although substantial differences exist among cities. Negative relationships between the number of cultural landmarks and major cover types were found, except with agricultural lands. Clearly, cultural landmarks need to be treated as “natural features” and considered as reference points in urban planning. Major efforts are needed to construct a global database before an overarching conclusion can be made for global cities.

Although it's well known that the carbon intensity from passenger transport of cities varies widely, few studies assessed the disparities of that in city-level and its underlying factors due to the limited availability of data, and thus developed effective strategies for different types of cities. This study is the first to present a comprehensive inventory of emissions from passenger transport on road for 360 cities in mainland China for 2018, based on the data from 5 transport modes and evaluated by combining distance-based and top-down fuel-based methods. In 2018, passenger transport on road in China emitted 1076 MtC. A large portion of CO2 emissions was identified in the southern and eastern coastal areas and capital cities. GDP, population, and policy were the major factors determining the total CO2 emissions, but not carbon intensity. Clustering analysis of carbon intensity and 9 socio-economic predictors, using a tree-based regression model, clustered the 360 cities into 6 groups and showed that higher carbon intensities occurred in both affluent city groups with a high active population share and less affluent city groups with a low population density but high density of trip destinations. Forward-and-backward stepwise multiple regression analysis indicated that constructing a compact city is more effective for city groups with a high income and high active population share. Enhancing land-use mixed degree is more critical for city groups with a high income and low active population share, while shortening travel distance by intensifying infrastructure construction is more important for the less affluent city groups.

The Mongolian Plateau hosts two different governments: the Mongolian People’s Republic and the Inner Mongolia Autonomous Region, a provincial-level government of the People’s Republic of China. The divergence between these governments has widened in the past century, mostly due to a series of institutional changes that generated different socioeconomic and demographic trajectories. Due to its high latitude and altitude, the Plateau has been highly sensitive to the rapid changes in global and regional climates that have altered the spatial and temporal distributions of energy and water. Based on a recent workshop to synthesize findings on the sustainability of the Plateau amidst socioeconomic and environmental change, we identify five critical issues facing the social-ecological systems (SES): (1) divergent and uncertain changes in social and ecological characteristics; (2) declining prevalence of nomadism; (3) consequences of rapid urbanization in transitional economies; (4) the unsustainability of large-scale afforestation efforts in the semi-arid and arid areas of Inner Mongolia; and (5) the role of institutional changes in shaping the SES on the Plateau. We emphasize that lessons learned in Inner Mongolia are valuable, but may not always apply to Mongolia. National land management policies and regulations have long-term effects on the sustainability of SES; climate change adaptation policies and practices must be tuned to local conditions and should be central to decision-making on natural resource management and socioeconomic development pathways.

In urban environments, green spaces have proven to act as ameliorating factors of some climatic features related to heat stress, reducing their effects and providing comfortable outdoor settings for people. In addition, green spaces have demonstrated greater capacity, compared with built-up areas, for promoting human health and well-being. In this paper, we present results of a study conducted in Italy with the general goal to contribute to the theoretical and empirical rationale for linking green spaces with well-being in urban environments. Specifically, the study focused on the physical and psychological benefits and the general well-being associated with the use of green spaces on people when heat stress episodes are more likely to occur. A questionnaire was set up and administered to users of selected green spaces in Italy (metropolitan area of Milan and Bari - n=400). Results indicate that longer and frequent visits of green spaces generate significant improvements of the perceived benefits and well-being among users. These results are consistent with the idea that the use of green spaces could alleviate the perception of thermal discomfort during periods of heat stress.

In recent decades, Mediterranean landscapes have been affected by human-induced drivers, such as land use and climate change. Forest ecosystems and landscapes have been particularly affected in mountainous regions due to limited management and stewardship, especially in remote areas. Therefore, there is a need to set up new strategies to enhance ecosystem services in forested areas which, in turn, will benefit local communities and economies. In this study, we implemented a new approach—Multiscale Mapping of Ecosystem Services (MIMOSE)—to assess ecosystem services in Mediterranean forests located in a mountainous region of Italy. We spatially assessed timber provision and carbon sequestration according to three forest management strategies: business-as-usual, maximizing economic values, and prioritizing conservation. Sustainable strategies for forest planning were identified at the landscape scale. We found that (i) timber provision is a conflicting service, especially when adaptation strategies are promoted; (ii) the most balanced set of forest ecosystem services is achieved through prioritizing conservation; and (iii) the ecosystem services availability is enhanced by optimizing the spatial allocation of different management strategies. Our approach is suitable to support landscape planning for balancing forest ecosystem potentialities while respecting local community needs and promoting sustainable development goals in the Mediterranean area.