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Showing papers in "Nature Climate Change in 2013"


Journal ArticleDOI
TL;DR: In this paper, the authors look at observations and model projections from 1923 to 2010, to test the ability of models to predict future drought conditions, which inspires confidence in their projections of drought.
Abstract: Historical records show increased aridity over many land areas since 1950. This study looks at observations and model projections from 1923 to 2010, to test the ability of models to predict future drought conditions. Models are able to capture the greenhouse-gas forcing and El Nino–Southern Oscillation mode for historical periods, which inspires confidence in their projections of drought.

3,385 citations


Journal ArticleDOI
TL;DR: This article used several climate models to estimate the global risk of flooding at the end of the century and showed that vulnerability is dependent on the degree of warming and the interannual variability in precipitation.
Abstract: Flood risk is expected to increase as the climate warms. This study, for the first time, uses several climate models to estimate the global risk of flooding at the end of the century. Projections show a large increase in flood frequency in some areas, whereas other regions can expect a decrease. Vulnerability is dependent on the degree of warming and the interannual variability in precipitation.

1,812 citations


Journal ArticleDOI
TL;DR: In this paper, the authors provide a quantification of present and future flood losses in the 136 largest coastal cities, using a new database of urban protection and different assumptions on adaptation, and account for existing and future flooding defences.
Abstract: Flood losses in coastal cities will rise due to increasing populations and assets. Research now quantifies average losses in the 136 largest coastal cities. Estimated at approximately US$6 billion in 2005, average annual losses could increase to US$52 billion by 2050 on the basis of projected socio-economic change alone. If climate change and subsidence are also considered, current protection will need to be upgraded to avoid unacceptable losses. Flood exposure is increasing in coastal cities1,2 owing to growing populations and assets, the changing climate3, and subsidence4,5,6. Here we provide a quantification of present and future flood losses in the 136 largest coastal cities. Using a new database of urban protection and different assumptions on adaptation, we account for existing and future flood defences. Average global flood losses in 2005 are estimated to be approximately US$6 billion per year, increasing to US$52 billion by 2050 with projected socio-economic change alone. With climate change and subsidence, present protection will need to be upgraded to avoid unacceptable losses of US$1 trillion or more per year. Even if adaptation investments maintain constant flood probability, subsidence and sea-level rise will increase global flood losses to US$60–63 billion per year in 2050. To maintain present flood risk, adaptation will need to reduce flood probabilities below present values. In this case, the magnitude of losses when floods do occur would increase, often by more than 50%, making it critical to also prepare for larger disasters than we experience today. The analysis identifies the cities that seem most vulnerable to these trends, that is, where the largest increase in losses can be expected.

1,592 citations


Journal ArticleDOI
TL;DR: In this article, the authors derived a forest drought-stress index (FDSI) for the southwestern United States using a comprehensive tree-ring data set representing AD 1000-2007, which is approximately equally influenced by the warm-season vapour-pressure deficit (largely controlled by temperature) and cold-season precipitation, together explaining 82% of the FDSI variability.
Abstract: As the climate changes, drought may reduce tree productivity and survival across many forest ecosystems; however, the relative influence of specific climate parameters on forest decline is poorly understood. We derive a forest drought-stress index (FDSI) for the southwestern United States using a comprehensive tree-ring data set representing AD 1000–2007. The FDSI is approximately equally influenced by the warm-season vapour-pressure deficit (largely controlled by temperature) and cold-season precipitation, together explaining 82% of the FDSI variability. Correspondence between the FDSI and measures of forest productivity, mortality, bark-beetle outbreak and wildfire validate the FDSI as a holistic forest-vigour indicator. If the vapour-pressure deficit continues increasing as projected by climate models, the mean forest drought-stress by the 2050s will exceed that of the most severe droughts in the past 1,000 years. Collectively, the results foreshadow twenty-first-century changes in forest structures and compositions, with transition of forests in the southwestern United States, and perhaps water-limited forests globally, towards distributions unfamiliar to modern civilization. As the global climate changes, drought is expected to reduce productivity and tree survival across many forests; however, the relative influence of climate variables on forest decline remains poorly understood. A drought-stress index based on tree-ring data—newly developed for the southwestern United States—is found to be equally influenced by evaporation (primarily temperature driven) and precipitation and may serve as a holistic forest-vigour indicator in water-limited forests.

1,562 citations


Journal ArticleDOI
TL;DR: In this paper, the authors critically review recent research assessing the impacts of climate on ground water through natural and human-induced processes as well as through groundwater-driven feedbacks on the climate system, and highlight the possible opportunities and challenges of using and sustaining groundwater resources in climate adaptation strategies.
Abstract: As the world's largest distributed store of fresh water, ground water plays a central part in sustaining ecosystems and enabling human adaptation to climate variability and change. The strategic importance of ground water for global water and food security will probably intensify under climate change as more frequent and intense climate extremes (droughts and floods) increase variability in precipitation, soil moisture and surface water. Here we critically review recent research assessing the impacts of climate on ground water through natural and human-induced processes as well as through groundwater-driven feedbacks on the climate system. Furthermore, we examine the possible opportunities and challenges of using and sustaining groundwater resources in climate adaptation strategies, and highlight the lack of groundwater observations, which, at present, limits our understanding of the dynamic relationship between ground water and climate.

1,536 citations


Journal ArticleDOI
TL;DR: This article synthesized all available studies of the consistency of marine ecological observations with expectations under climate change This yielded a meta-database of 1,735 marine biological responses for which either regional or global climate change was considered as a driver.
Abstract: Research that combines all available studies of biological responses to regional and global climate change shows that 81–83% of all observations were consistent with the expected impacts of climate change These findings were replicated across taxa and oceanic basins Past meta-analyses of the response of marine organisms to climate change have examined a limited range of locations1,2, taxonomic groups2,3,4 and/or biological responses5,6 This has precluded a robust overview of the effect of climate change in the global ocean Here, we synthesized all available studies of the consistency of marine ecological observations with expectations under climate change This yielded a meta-database of 1,735 marine biological responses for which either regional or global climate change was considered as a driver Included were instances of marine taxa responding as expected, in a manner inconsistent with expectations, and taxa demonstrating no response From this database, 81–83% of all observations for distribution, phenology, community composition, abundance, demography and calcification across taxa and ocean basins were consistent with the expected impacts of climate change Of the species responding to climate change, rates of distribution shifts were, on average, consistent with those required to track ocean surface temperature changes Conversely, we did not find a relationship between regional shifts in spring phenology and the seasonality of temperature Rates of observed shifts in species’ distributions and phenology are comparable to, or greater, than those for terrestrial systems

1,504 citations


Journal ArticleDOI
TL;DR: In this article, the authors compare projections from the latest models with those from earlier versions and find that the spread of results has not changed significantly, and some of the spread will always remain due to the internal variability of the climate system.
Abstract: Updated models are being used for the new assessment report from the Intergovernmental Panel on Climate Change. This study compares projections from the latest models with those from earlier versions. The spread of results has not changed significantly, and some of the spread will always remain due to the internal variability of the climate system. As models improve, they are able to represent more processes in greater detail, allowing for greater confidence in their projections, in spite of model spread.

1,363 citations


Journal ArticleDOI
TL;DR: In this article, the potential benefits of conservation, restoration and use of marine vegetated habitats for coastal protection and climate change mitigation are assessed, and the potential benefit of using these habitats in eco-engineering solutions for coast protection is discussed.
Abstract: Marine vegetated habitats occupy a small fraction of the ocean surface, but contribute about 50% of the carbon that is buried in marine sediments. In this Review the potential benefits of conservation, restoration and use of these habitats for coastal protection and climate change mitigation are assessed. Marine vegetated habitats (seagrasses, salt-marshes, macroalgae and mangroves) occupy 0.2% of the ocean surface, but contribute 50% of carbon burial in marine sediments. Their canopies dissipate wave energy and high burial rates raise the seafloor, buffering the impacts of rising sea level and wave action that are associated with climate change. The loss of a third of the global cover of these ecosystems involves a loss of CO2 sinks and the emission of 1 Pg CO2 annually. The conservation, restoration and use of vegetated coastal habitats in eco-engineering solutions for coastal protection provide a promising strategy, delivering significant capacity for climate change mitigation and adaption.

1,239 citations


Journal ArticleDOI
TL;DR: In this article, the authors present the largest standardized model intercomparison for climate change impacts so far, finding that individual crop models are able to simulate measured wheat grain yields accurately under a range of environments, particularly if the input information is sufficient.
Abstract: Projections of climate change impacts on crop yields are inherently uncertain(1). Uncertainty is often quantified when projecting future greenhouse gas emissions and their influence on climate(2). However, multi-model uncertainty analysis of crop responses to climate change is rare because systematic and objective comparisons among process-based crop simulation models(1,3) are difficult(4). Here we present the largest standardized model intercomparison for climate change impacts so far. We found that individual crop models are able to simulate measured wheat grain yields accurately under a range of environments, particularly if the input information is sufficient. However, simulated climate change impacts vary across models owing to differences in model structures and parameter values. A greater proportion of the uncertainty in climate change impact projections was due to variations among crop models than to variations among downscaled general circulation models. Uncertainties in simulated impacts increased with CO2 concentrations and associated warming. These impact uncertainties can be reduced by improving temperature and CO2 relationships in models and better quantified through use of multi-model ensembles. Less uncertainty in describing how climate change may affect agricultural productivity will aid adaptation strategy development and policymaking.

1,049 citations


Journal ArticleDOI
TL;DR: In this article, the authors analyzed important new research from across the social sciences and found that climate change threatens important cultural dimensions of people's lives and livelihoods, including material and lived aspects of culture, identity, community cohesion and sense of place.
Abstract: Society's response to climate change is inevitably mediated by culture. In a Review Article that analyses important new research from across the social sciences, climate change is shown to threaten important cultural dimensions of people's lives and livelihoods — including material and lived aspects of culture, identity, community cohesion and sense of place.

992 citations


Journal ArticleDOI
TL;DR: In this article, the societal and ecological consequences of forest die-off are considered. But the authors do not consider the impact of forest mortality on terrestrial ecosystems, climate-ecosystem interactions, and carbon-cycle feedbacks.
Abstract: The multitude of forest die-off events within the last decade strongly suggests that forest mortality is an emerging global phenomenon, constituting a major uncertainty in projections of climate impacts on terrestrial ecosystems, climate-ecosystem interactions, and carbon-cycle feedbacks. This Review considers the societal and ecological consequences of dying forests.

Journal ArticleDOI
TL;DR: In 2011, the waters along the west coast of Australia experienced an unprecedented (in recorded times) warming event with warming anomalies of 2-4°C that persisted for more than ten weeks.
Abstract: In 2011 the waters along the west coast of Australia—a global hotspot of biodiversity—experienced an unprecedented (in recorded times) warming event with warming anomalies of 2–4 °C that persisted for more than ten weeks. Now research shows that biodiversity patterns of temperate seaweeds, invertebrates and fishes were significantly different following the warming event.

Journal ArticleDOI
TL;DR: The latest carbon dioxide emissions continue to track the high end of emission scenarios, making it even less likely global warming will stay below 2 °C as mentioned in this paper, with a probable reliance on net negative emissions in the longer term.
Abstract: The latest carbon dioxide emissions continue to track the high end of emission scenarios, making it even less likely global warming will stay below 2 °C A shift to a 2 °C pathway requires immediate significant and sustained global mitigation, with a probable reliance on net negative emissions in the longer term

Journal ArticleDOI
TL;DR: This paper showed that under forecasted changes in temperature and precipitation, there could be a decline of economically valuable species, which would lead to a loss in the value of European forest land.
Abstract: European forests are threatened by climate change with impacts on the distribution of tree species. Previous discussions on the consequences of biome shifts have concentrated only on ecological issues; however, research now shows that under forecasted changes in temperature and precipitation there could be a decline of economically valuable species, which would lead to a loss in the value of European forest land.

Journal ArticleDOI
TL;DR: In this paper, an Earth System Model (ESM) that explicitly represents microbial soil carbon cycling mechanisms is used to simulate carbon pools that closely match observations and produce a much wider range of soil carbon responses to climate change over the twenty-first century.
Abstract: Earth system models (ESMs) generally have crude representations of the responses of soil carbon responses to changing climate. Now an ESM that explicitly represents microbial soil carbon cycling mechanisms is able to simulate carbon pools that closely match observations. Projections from this model produce a much wider range of soil carbon responses to climate change over the twenty-first century than conventional ESMs.

Journal ArticleDOI
TL;DR: In this article, a process-based agricultural production system simulator (APSIM) is used to simulate the effects of extreme degree days (EDD) on maize yields in the United States.
Abstract: Statistical studies of rainfed maize yields in the United States(1) and elsewhere(2) have indicated two clear features: a strong negative yield response to accumulation of temperatures above 30 degrees C (or extreme degree days (EDD)), and a relatively weak response to seasonal rainfall. Here we show that the process-based Agricultural Production Systems Simulator (APSIM) is able to reproduce both of these relationships in the Midwestern United States and provide insight into underlying mechanisms. The predominant effects of EDD in APSIM are associated with increased vapour pressure deficit, which contributes to water stress in two ways: by increasing demand for soil water to sustain a given rate of carbon assimilation, and by reducing future supply of soil water by raising transpiration rates. APSIM computes daily water stress as the ratio of water supply to demand, and during the critical month of July this ratio is three times more responsive to 2 degrees C warming than to a 20% precipitation reduction. The results suggest a relatively minor role for direct heat stress on reproductive organs at present temperatures in this region. Effects of elevated CO2 on transpiration efficiency should reduce yield sensitivity to EDD in the coming decades, but at most by 25%.

Journal ArticleDOI
TL;DR: Observations of hundreds of pests and pathogens reveal an average poleward shift of 2.7±0.8 km yr−1 since 1960, supporting the hypothesis of climate-driven pest movement.
Abstract: The extent to which crop pests and pathogens have altered their latitudinal ranges in response to climate change remains largely unknown. Now observations of hundreds of pests and pathogens reveal an average poleward shift of 2.7±0.8 km yr−1 since 1960, supporting the hypothesis of climate-driven pest movement.

Journal ArticleDOI
TL;DR: The authors showed that climate change could lead to a major redistribution of vegetation across the Arctic, with important implications for biosphere-atmosphere interactions, as well as for biodiversity conservation and ecosystem services.
Abstract: This study shows that climate change could lead to a major redistribution of vegetation across the Arctic, with important implications for biosphere–atmosphere interactions, as well as for biodiversity conservation and ecosystem services. Woody vegetation is predicted to expand substantially over coming decades, causing more Arctic warming through positive climate feedbacks than previously thought.

Journal ArticleDOI
TL;DR: In this article, the authors calculate a hazard index for every 1 km 2 of the United States coastline and use this index to identify the most vulnerable people and property as indicated by being in the upper quartile of hazard for the nation's coastline.
Abstract: Extreme weather, sea-level rise and degraded coastal ecosystems are placing people and property at greater risk of damage from coastal hazards 1‐5 . The likelihood and magnitude of losses may be reduced by intact reefs and coastal vegetation 1 , especially when those habitats fringe vulnerable communities and infrastructure. Using five sea-level-rise scenarios, we calculate a hazard index for every 1 km 2 of the United States coastline. We use this index to identify the most vulnerable people and property as indicated by being in the upper quartile of hazard for the nation’s coastline. The number of people, poor families, elderly and total value of residential property that are most exposed to hazards can be reduced by half if existing coastal habitats remain fully intact. Coastal habitats defend the greatest number of people and total property value in Florida, New York and California. Our analyses deliver the first national map of risk reduction owing to natural habitats and indicates where conservation and restoration of reefs and vegetation have the greatest potential to protect coastal communities. Globally, coastal flooding and sea level are expected to increase significantly by mid-century, with potentially severe consequences for coastal populations around the world 6 . In the United States

Journal ArticleDOI
TL;DR: In this paper, the authors measured the temperature response of microbial efficiency in soils amended with substrates varying in lability, and found that the efficiency with which soil microorganisms use organic matter is dependent on both temperature and substrate quality, with efficiency declining with increasing temperatures for more recalcitrant substrates.
Abstract: Soils are the largest repository of organic carbon in the terrestrial biosphere. Nevertheless, relatively little is known about the factors controlling the efficiency with which microbial communities utilize carbon, and its effect on soil–atmosphere CO2 exchange. Now research using long-term experimental plots suggests that climate warming could alter the decay dynamics of more stable organic-matter compounds with implications for carbon storage in soils and ultimately climate warming. Soils are the largest repository of organic carbon (C) in the terrestrial biosphere and represent an important source of carbon dioxide (CO2) to the atmosphere, releasing 60–75 Pg C annually through microbial decomposition of organic materials1,2. A primary control on soil CO2 flux is the efficiency with which the microbial community uses C. Despite its critical importance to soil–atmosphere CO2 exchange, relatively few studies have examined the factors controlling soil microbial efficiency. Here, we measured the temperature response of microbial efficiency in soils amended with substrates varying in lability. We also examined the temperature sensitivity of microbial efficiency in response to chronic soil warming in situ. We find that the efficiency with which soil microorganisms use organic matter is dependent on both temperature and substrate quality, with efficiency declining with increasing temperatures for more recalcitrant substrates. However, the utilization efficiency of a more recalcitrant substrate increased at higher temperatures in soils exposed to almost two decades of warming 5 °C above ambient. Our work suggests that climate warming could alter the decay dynamics of more stable organic matter compounds, thereby having a positive feedback to climate that is attenuated by a shift towards a more efficient microbial community in the longer term.

Journal ArticleDOI
TL;DR: A modelling study into the integrated effects of these various changes on fish body size suggests that averaged maximum body weight could fall by 14–24% globally by 2050.
Abstract: In the ocean, biological responses to climate change include altered distribution, phenology and productivity. A modelling study into the integrated effects of these various changes on fish body size suggests that averaged maximum body weight could fall by 14–24% globally by 2050. About half of the decline is accounted for by changes in distribution and abundance, with the remainder being physiological.

Journal ArticleDOI
TL;DR: Research now indicates that temperature and vegetation seasonality in northern ecosystems have diminished to an extent equivalent to a southerly shift of 4°– 7° in latitude, and may reach the equivalent of up to 20° over the twenty-first century.
Abstract: Pronounced increases in winter temperature result in lower seasonal temperature differences, with implications for vegetation seasonality and productivity. Research now indicates that temperature and vegetation seasonality in northern ecosystems have diminished to an extent equivalent to a southerly shift of 4°– 7° in latitude, and may reach the equivalent of up to 20° over the twenty-first century.

Journal ArticleDOI
TL;DR: In this paper, the authors present a new paradigm for resource assessment called CLEWs (climate, land-use, energy and water strategies), which can help to remedy some of these shortcomings.
Abstract: Land, energy and water are our most precious resources, but the manner and extent to which they are exploited contributes to climate change. Meanwhile, the systems that provide these resources are themselves highly vulnerable to changes in climate. Efficient resource management is therefore of great importance, both for mitigation and for adaptation purposes. We postulate that the lack of integration in resource assessments and policy-making leads to inconsistent strategies and inefficient use of resources. We present CLEWs (climate, land-use, energy and water strategies), a new paradigm for resource assessments that we believe can help to remedy some of these shortcomings.

Journal ArticleDOI
TL;DR: A conceptual model that links unfavourable ratios of dissolved inorganic nutrients in the water column with established mechanisms of coral bleaching improves the understanding of the detrimental effects of coastal nutrient enrichment on coral reefs, which is urgently required to support knowledge-based management strategies to mitigate the effects of climate change.
Abstract: Mass coral bleaching, resulting from the breakdown of coral-algal symbiosis has been identified as the most severe threat to coral reef survival on a global scale. Regionally, nutrient enrichment of reef waters is often associated with a significant loss of coral cover and diversity. Recently, increased dissolved inorganic nitrogen concentrations have been linked to a reduction of the temperature threshold of coral bleaching, a phenomenon for which no mechanistic explanation is available. Here we show that increased levels of dissolved inorganic nitrogen in combination with limited phosphate concentrations result in an increased susceptibility of corals to temperature-and light-induced bleaching. Mass spectrometric analyses of the algal lipidome revealed a marked accumulation of sulpholipids under these conditions. Together with increased phosphatase activities, this change indicates that the imbalanced supply of dissolved inorganic nitrogen results in phosphate starvation of the symbiotic algae. Based on these findings we introduce a conceptual model that links unfavourable ratios of dissolved inorganic nutrients in the water column with established mechanisms of coral bleaching. Notably, this model improves the understanding of the detrimental effects of coastal nutrient enrichment on coral reefs, which is urgently required to support knowledge-based management strategies to mitigate the effects of climate change. © 2013 Macmillan Publishers Limited. All rights reserved.

Journal ArticleDOI
TL;DR: In this paper, the first community-derived multi-model ensemble of wind-wave climate projections show agreement over extended regions of the global ocean and large uncertainty in available wave-climate projections is found to be due to downscaling methods.
Abstract: Changing wind-wave climate has the potential to exacerbate, or negate, the impacts of sea-level rise in coastal zones. Results from the first community-derived multi-model ensemble of wind-wave climate projections show agreement over extended regions of the global ocean. Large uncertainty in available wave-climate projections is found to be due to downscaling methods.

Journal ArticleDOI
TL;DR: In this article, the extent of land-cover change caused by people is analyzed. But the authors focus on the terrestrial water cycle and do not consider the effects of human impacts on it.
Abstract: Human impacts on the terrestrial water cycle have the potential to influence hazards such as flooding and drought, so understanding the extent of our influence is an important research goal. A study utilizing estimates of evapotranspiration for different types of land cover and a database of changes in use now shows that the extent of land-cover change caused by people is already an important factor affecting the terrestrial water cycle.

Journal ArticleDOI
TL;DR: Analysis of the sensitivities of five animal groups to a wide range of CO2 concentrations finds a variety of responses within and between taxa, indicating that acidification will drive substantial changes in ocean ecosystems this century.
Abstract: The severity of the ecological threat posed by ocean acidification remains poorly understood. Now analysis of the sensitivities of five animal groups to a wide range of CO2 concentrations finds a variety of responses within and between taxa, indicating that acidification will drive substantial changes in ocean ecosystems this century.

Journal ArticleDOI
TL;DR: Air quality and health co-benefits, especially as they are mainly local and near-term, provide strong additional motivation for transitioning to a low-carbon future.
Abstract: Actions to reduce greenhouse gas (GHG) emissions often reduce co-emitted air pollutants, bringing co-benefits for air quality and human health. Past studies1-6 typically evaluated near-term and local co-benefits, neglecting the long-range transport of air pollutants7-9, long-term demographic changes, and the influence of climate change on air quality10-12. Here we simulate the co-benefits of global GHG reductions on air quality and human health using a global atmospheric model and consistent future scenarios, via two mechanisms: a) reducing co-emitted air pollutants, and b) slowing climate change and its effect on air quality. We use new relationships between chronic mortality and exposure to fine particulate matter13 and ozone14, global modeling methods15, and new future scenarios16. Relative to a reference scenario, global GHG mitigation avoids 0.5±0.2, 1.3±0.5, and 2.2±0.8 million premature deaths in 2030, 2050, and 2100. Global average marginal co-benefits of avoided mortality are $50-380 (ton CO2)-1, which exceed previous estimates, exceed marginal abatement costs in 2030 and 2050, and are within the low range of costs in 2100. East Asian co-benefits are 10-70 times the marginal cost in 2030. Air quality and health co-benefits, especially as they are mainly local and near-term, provide strong additional motivation for transitioning to a low-carbon future.

Journal ArticleDOI
TL;DR: This article showed that the uncertainties associated with the projection of climate extremes are mainly due to internal climate variability and that model projections are consistent when averaged across regions, allowing robust projection of future extremes.
Abstract: There are large uncertainties associated with the projection of climate extremes. This study shows that the uncertainties are mainly due to internal climate variability. However, model projections are consistent when averaged across regions, allowing robust projection of future extremes.

Journal ArticleDOI
TL;DR: In this paper, a new global measure of precipitation seasonality is proposed, and application of this method to observations from the tropics shows that increases in variability were accompanied by shifts in seasonal magnitude, timing and duration.
Abstract: Climate change is altering the seasonal distribution, interannual variability and overall magnitude of precipitation. A new global measure of precipitation seasonality is proposed, and application of this method to observations from the tropics shows that increases in variability were accompanied by shifts in seasonal magnitude, timing and duration.