• Energy Research

AbstractThe urban heat island (UHI) has a negative impact on the health of urban residents by increasing average temperatures. The intensity of the UHI effect is influenced by urban geometry and the amount of vegetation cover. This study investigated the impact of urban growth and loss of vegetation cover on the UHI in a subtropical city (Brisbane, Australia) during average and extreme conditions using the Conformal Cubic Atmospheric Model, run at a 1-km spatial resolution for 10 years. The average nighttime temperature increase was 0.7°C for the “Medium Density” urban growth scenario and 1.8°C for the “No Vegetation” scenario. During two widespread extreme heat events, the mean maximum increase in urban temperatures above the Control was between 2.2° and 3.8°C in the No Vegetation scenario and between 0.3° and 1.6°C in the Medium Density urban growth scenario. The results are similar to previous findings for temperate cities, with the intensity of the UHI effect higher at night and during winter than during the day and summer. Vegetation cover had the strongest impact on temperatures, more so than building height and height/width ratio. Maintaining and restoring vegetation, therefore, is a key consideration in mitigating the urban heat island. The large temperature increases found in this study, particularly during extreme heat events, shows the importance of reducing the UHI for protecting the health of urban residents, and this should be a priority in urban landscape planning and design.

AbstractProtecting biomass carbon stocks to mitigate climate change has direct implications for biodiversity conservation. Yet, evidence that a positive association exists between carbon density and species richness is contrasting. Here, we test how this association varies (1) across spatial extents and (2) as a function of how strongly carbon and species richness depend on environmental variables. We found the correlation weakens when moving from larger extents, e.g. realms, to narrower extents, e.g. ecoregions. For ecoregions, a positive correlation emerges when both species richness and carbon density vary as functions of the same environmental variables (climate, soil, elevation). In 20% of tropical ecoregions, there are opportunities to pursue carbon conservation with direct biodiversity co‐benefits, while other ecoregions require careful planning for both species and carbon to avoid potentially perverse outcomes. The broad assumption of a linear relationship between carbon and biodiversity can lead to undesired outcomes.

An increased understanding of the current and potential future impacts of climate change has significantly influenced conservation in practice in recent years. Climate change has necessitated a shift toward longer planning time horizons, moving baselines, and evolving conservation goals and targets. This shift has resulted in new perspectives on, and changes in, the basic approaches practitioners use to conserve biodiversity. Restoration, spatial planning and reserve selection, connectivity modelling, extinction risk assessment, and species translocations have all been reimagined in the face of climate change. Restoration is being conducted with a new acceptance of uncertainty and an understanding that goals will need to shift through time. New conservation targets, such as geophysical settings and climatic refugia, are being incorporated into conservation plans. Risk assessments have begun to consider the potentially synergistic impacts of climate change and other threats. Assisted colonization has gained acceptance in recent years as a viable and necessary conservation tool. This evolution has paralleled a larger trend in conservation—a shift toward conservation actions that benefit both people and nature. As we look forward, it is clear that more change is on the horizon. To protect biodiversity and essential ecosystem services, conservation will need to anticipate the human response to climate change and to focus not only on resistance and resilience but on transitions to new states and new ecosystems.

Understanding the scale, location and nature conservation values of the lands over which Indigenous Peoples exercise traditional rights is central to implementation of several global conservation and climate agreements. However, spatial information on Indigenous lands has never been aggregated globally. Here, using publicly available geospatial resources, we show that Indigenous Peoples manage or have tenure rights over at least ~38 million km2 in 87 countries or politically distinct areas on all inhabited continents. This represents over a quarter of the world’s land surface, and intersects about 40% of all terrestrial protected areas and ecologically intact landscapes (for example, boreal and tropical primary forests, savannas and marshes). Our results add to growing evidence that recognizing Indigenous Peoples’ rights to land, benefit sharing and institutions is essential to meeting local and global conservation goals. The geospatial analysis presented here indicates that collaborative partnerships involving conservation practitioners, Indigenous Peoples and governments would yield significant benefits for conservation of ecologically valuable landscapes, ecosystems and genes for future generations.

AbstractAimHuman activities are largely responsible for the processes that threaten biodiversity, yet potential changes in human behaviour as a response to climate change are ignored in most species and site‐based vulnerability assessments (VAs). Here we assess how incorporation of the potential impact of climate change on humans alters our view of vulnerability when using well‐established site and species VA methodologies.LocationSouthern Africa.MethodsOur baseline was two published studies that used accepted VA methodologies aimed at examining the direct impacts of climate changes on species and sites. The first identified potential shifts in the distributions of 164 restricted‐range avian species, the second forecasted species turnover in 331 Important Bird and Biodiversity Areas (IBAs). We used a published spatially explicit assessment of potential climate change impacts on people to evaluate which species and sites overlap with human populations most likely to be impacted. By doing this, we were able to assess how the integration of potential climate impacts on human populations changes our perception of which species and sites are most vulnerable to climate change.ResultsWe found no correlation between species and sites most likely to be impacted directly by climate change and those where the potential response of human populations could drive major indirect impacts. The relative vulnerability of individual species and sites shifted when potential impacts of climate change on human communities were considered, with more than one‐fifth of species and one‐tenth of sites moving from ‘low’ to ‘high’ risk.Main conclusionsStandard VA methodologies that fail to consider how people are likely to respond to climate change will result in systematically biased assessments. This may lead to the implementation of inappropriate management actions, and a failure to address those species or sites that may be uniquely, or additionally, imperilled by the impacts of human responses to climate change.

AbstractHabitat loss is the greatest threat to biodiversity and rapid, human-forced climate change is likely to exacerbate this. Here we present the first global assessment of current and potential future impacts on biodiversity of a habitat loss and fragmentation–climate change (HLF–CC) interaction. A recent meta-analysis demonstrated that the negative impacts of habitat loss and fragmentation have been disproportionately severe in areas with high temperatures in the warmest month and declining rainfall, although impacts also varied across vegetation types. We compiled an integrated global database of past, current and future climate variables and past vegetation loss to identify ecoregions where (i) past climate change is most likely to have exacerbated the impacts of HLF, and (ii) forecasted climate change is most likely to exacerbate the impacts of HLF in the future. We found that recent climate change is likely (probability >66%) to have exacerbated the impacts of HLF in 120 (18.5%) ecoregions. Impacted ecoregions are disproportionately biodiverse, containing over half (54.1%) of all known terrestrial amphibian, bird, mammal, and reptile species. Forecasts from the RCP8.5 emissions scenario suggest that nearly half of ecoregions globally (n=283, 43.5%) will become impacted during the 21st century. To minimize ongoing and future HLF–CC impacts on biodiversity, ecoregions where impacts are most likely must become priorities for proactive conservation actions that avoid loss of native vegetation (e.g., protected area establishment). Highly degraded ecoregions where impacts are most likely should be priorities for restoration and candidates for unconventional conservation actions (e.g. translocation of species).

A comprehensive summary of studies that simulate climate change impacts on agriculture are now reported in a meta-analysis. Findings suggest that, without measures to adapt to changing conditions, aggregate yield losses should be expected for wheat, rice and maize in temperate and tropical growing regions even under relatively moderate levels of local warming.