Hydrologic resilience of the terrestrial biosphere Gerten, Dieter; Lucht, Wolfgang; Schaphoff, Sibyll ...
Geophysical research letters,
November 2005, Letnik:
32, Številka:
21
Journal Article, Magazine Article
Recenzirano
Odprti dostop
We quantify the extent to which net primary production (NPP) of terrestrial ecosystems is water‐limited under future atmospheric CO2 enrichment and climate change. Analysis is based on spatially ...explicit simulations with a Dynamic Global Vegetation Model (DGVM) forced by climate projections from five different General Circulation Models (GCMs) under one emission scenario. We find for many but not all regions that NPP will be less water‐limited despite concurrent declines in soil moisture, owing to a frail balance of unfavorable climate effects on soil moisture, reduced transpiration by CO2‐induced lower stomatal aperture, and continuous acclimation of vegetation.
Observation‐based and modeling studies have identified the Eastern Mediterranean and Middle East (EMME) region as a prominent climate change hotspot. While several initiatives have addressed the ...impacts of climate change in parts of the EMME, here we present an updated assessment, covering a wide range of timescales, phenomena and future pathways. Our assessment is based on a revised analysis of recent observations and projections and an extensive overview of the recent scientific literature on the causes and effects of regional climate change. Greenhouse gas emissions in the EMME are growing rapidly, surpassing those of the European Union, hence contributing significantly to climate change. Over the past half‐century and especially during recent decades, the EMME has warmed significantly faster than other inhabited regions. At the same time, changes in the hydrological cycle have become evident. The observed recent temperature increase of about 0.45°C per decade is projected to continue, although strong global greenhouse gas emission reductions could moderate this trend. In addition to projected changes in mean climate conditions, we call attention to extreme weather events with potentially disruptive societal impacts. These include the strongly increasing severity and duration of heatwaves, droughts and dust storms, as well as torrential rain events that can trigger flash floods. Our review is complemented by a discussion of atmospheric pollution and land‐use change in the region, including urbanization, desertification and forest fires. Finally, we identify sectors that may be critically affected and formulate adaptation and research recommendations toward greater resilience of the EMME region to climate change.
Key Points
The Eastern Mediterranean and Middle East is warming almost two times faster than the global average and other inhabited parts of the world
Climate projections indicate a future warming, strongest in summers. Precipitation will likely decrease, particularly in the Mediterranean
Virtually all socio‐economic sectors will be critically affected by the projected changes
The coupled global carbon and water cycles are influenced by multiple factors of human activity such as fossil‐fuel emissions and land use change. We used the LPJmL Dynamic Global Vegetation Model ...(DGVM) to quantify the potential influences of human demography, diet, and land allocation, and compare these to the effects of fossil‐fuel emissions and corresponding climate change. For this purpose, we generate 12 land use patterns in which these factors are analyzed in a comparative static setting, providing information on their relative importance and the range of potential impacts on the terrestrial carbon and water balance. We show that these aspects of human interference are equally important to climate change and historic fossil‐fuel emissions for global carbon stocks but less important for net primary production (NPP). Demand for agricultural area and thus the magnitude of impacts on the carbon and water cycles are mainly determined by constraints on localizing agricultural production and modulated by total demand for agricultural products.
Display omitted
•All ecosystem services categories are relevant for the Aichi Targets and the SDGs.•There is an information bias towards the supply side of ecosystem services.•Information on social ...behaviour and governance is lacking for ecosystem services flows.•Trade-offs caused by unsustainable development will likely remain undetected.•IPBES and national statistical bureaus offer an opportunity to improve ecosystem services assessments.
Global sustainability policies, such as the Sustainable Development Goals (SDGs) or the Aichi Targets, aim to ensure sustainable development, including improved human well-being and the conservation of nature. Although not yet explicitly used to evaluate the progress towards sustainable development, the ecosystem service concept implies a direct link between biodiversity and human well-being. This study explores how and which ecosystem services are currently considered in the SDGs and the Aichi Targets. We also identify which information might be already available for monitoring the progress towards their goals by reviewing national ecosystem assessments. This allows the identification of the main knowledge gaps for monitoring progress towards these global sustainability targets.
There is a wealth of information on all major ecosystem services categories which is directly relevant for the Aichi Targets and the SDGs. The top 25% most cited ecosystem services across both policy documents are: Natural heritage and diversity, Capture fisheries, Aquaculture, Water purification, Crops, Cultural heritage & diversity and Livestock. Most monitoring information recommended for the global sustainability goals, as well as in the information available from national assessments, is biased towards supply related aspects of ecosystem services flows. In contrast, there is much less information on social behaviour, use, demand and governance measures. Indicators are rarely available for all aspects of a specific ecosystem service.
The national statistical bureaus currently in charge of providing observations for reporting on SDGs, could be well placed to address this bias, by integrating ecological observations with socio-economic statistics into socio-ecological indicators for ecosystem services flows. IPBES can potentially address the gaps identified in this paper by improving coverage of the different dimensions of ecosystem services flows.
•We present land change scenarios for the Mediterranean driven by global change.•Yield improvements influence the expansion of rainfed and irrigated cropland.•Limiting water resources significantly ...affects modeling land system change.•Improving the state of water resources while increasing food production is possible.•Expanding the network of protected areas does not impact food production.
The Mediterranean region faces significant challenges to supply its growing population with food and living space. The region’s potential to do so in the future is even more uncertain in the light of global change effects. Climate change will impact water availability in the region, which is already limited and often used at unsustainable rates. To investigate the effects of global change and explore alternative development pathways of Mediterranean land use, we simulated two future scenarios with different land, water and biodiversity management transitions. We adopted a land systems approach, where land use and land cover are combined with data on land management, irrigation and livestock density, taking into account the characteristics of Mediterranean multifunctional landscapes, specific agricultural products, such as permanent crops, and irrigation water demands. Future land system changes were explored using the CLUMondo model for different development pathways of the region. We constrained the withdrawal of irrigation water based on existing freshwater resources. In a ‘growth’ scenario, we simulated a hypothetical future without consideration of environmental constraints and where food production and urban expansion are main priorities. The ‘sustainability’ scenario represents a future where limited water resources are extracted in a sustainable way and where areas of high biodiversity value are protected. The growth scenario projected significant intensification of land management, and loss of agro-silvo-pastoral mosaic systems. To achieve this, we calculate that the region would need to increase water withdrawal for irrigation significantly, resulting in increased pressure on freshwater resources. The sustainability scenario presents a way of increasing food production and at the same time improving the state of water resources, wetlands and traditional landscapes. Achieving this future would require improvements of yields of rain-fed systems and efficiencies of irrigated systems. The results indicate that coordinated environmental policy together with appropriate market access are needed to steer the regions land management towards a more sustainable future while ensuring food production.
1. A major challenge of current ecological research is to determine the responses of plant and animal communities and ecosystem processes to fulture environmental conditions. Ecosystems respond to ...climate change in complex ways, and the outcome may significantly depend on biodiversity. 2. We studied the relative effects of enhanced drought and of plant species mixture on soil biota and on litter decomposition in a Mediterranean oak forest. We experimentally reduced precipitation, accounting for seasonal precipitation variability, and created a single-species litter (Quercus pubescens), a two-species litter mixture (Q. pubescens + Acer monspessulanum) and a three-species litter mixture (Q. pubescens + A. monspessulanum + Cotinus coggygria). 3. In general, drier conditions affected decomposers negatively, directly by reducing fungal biomass and detritivorous mesofauna, and also indirectly by increasing the predation pressure on detritivorous mesofauna by predatory mesofauna. This is reflected under drier conditions in that Collembola abundance decreased more strongly than Acari abundance. One Collembola group (i.e. Neelipleona) even disappeared completely. 4. Increased drought strongly decreased litter decomposition rates. Mixed litter with two and three plant species positively affected soil biota communities and led to a more efficient litter decomposition process, probably through a greater litter quality. Faster decomposition in mixed litter can thus compensate slower decomposition rates under drier condition. 5. Synthesis. Our results highlight that, within our study system, drier climate strongly impacts on soil biodiversity and hence litter decomposition. Species-rich litter may mitigate such a decline in decomposition rates. Diverse plant communities should hence be maintained to reduce shifts in ecosystem functioning under climate change.
•We assessed the impact of urbanisation on ES supply over the period 1990–2012.•The peri-urban area of 12 Mediterranean cities in Europe and North Africa was analysed.•Land cover data and an ...expert-based method were employed.•Overall urban area increased at the expenses of decreasing agricultural land.•Ecosystem service provided by the Mediterranean peri-urban areas was reduced.
Urbanization is an important driver of changes in land cover in the Mediterranean Basin and it is likely to impact the supply and demand of ecosystem services (ES). The most significant land cover changes occur in the peri-urban zone, but little is known about how these changes affect the ES supply. For eight European and four North African cities, we have quantified changes in peri-urban land cover, for periods of sixteen years (1990–2006) in the Northern African, and twenty-two years (1990–2012) in the European cities, respectively. Using an expert-based method, we derived quantitative estimates of the dynamics in the supply of twenty-seven ES. The nature of land cover changes slightly differed between European and North African Mediterranean cities, but overall it increased in urban areas and decreased in agricultural land. The capacity of the peri-urban areas of Mediterranean cities to supply ES generally reduced over the last 20–30 years. For nine ES the potential supply actually increased for all four North African cities and three out of the eight European cities. Across all cities, the ES timber, wood fuel and religious and spiritual experience increased.
Given the expected increase of urban population in the Mediterranean Basin and the current knowledge of ES deficits in urban areas, the overall decrease in ES supply capacity of peri-urban areas is a risk for human well-being in the Mediterranean and poses a serious challenge for the Sustainable Development Goals in the Mediterranean basin.
. Plant functional traits and types are useful concepts in relation to disturbance responses of natural and managed ecosystems. To explore their applicability in greater depth, a set of 12 papers ...presents a broad range of issues from methodologies to the results of particular trait studies in the field, and modelling approaches. So far, empirical studies have only allowed us to identify a few functional traits that are consistently associated with disturbance. To determine the trait variations associated with climate, disturbance history and current disturbance regime as well as the interactions between these factors, global‐scale comparisons of numerous individual studies are required. Significant advances toward this ambitious goal are presented in these papers, and include: (1) the articulation of experimental and analytical methodologies for individual studies that could usefully contribute to a global comparison; (2) the identification of core traits that can be used in the further search for disturbance‐related traits common to a range of environments; (3) further information on vegetation response to disturbance in terms of trait representation, and the identification of attribute syndromes; (4) the identification of issues for modelling disturbance dynamics using functional types.
PDF
