Showing papers in "Nature Climate Change in 2015"
University of Massachusetts Amherst1, National Oceanic and Atmospheric Administration2, Université du Québec à Montréal3, Newcastle University4, University of Bern5, Chinese Academy of Sciences6, Rutgers University7, École Polytechnique Fédérale de Lausanne8, University of Graz9, University of Reading10, Shanxi University11, University of Alberta12, Environment Canada13
TL;DR: In this paper, the authors review important mechanisms that contribute towards elevation-dependent warming, such as snow albedo and surface-based feedbacks, water vapour changes and latent heat release, surface water vapours and radiative flux changes, surface heat loss and temperature change; and aerosols.
Abstract: There is growing evidence that the rate of warming is amplified with elevation, such that high-mountain environments experience more rapid changes in temperature than environments at lower elevations. Elevation-dependent warming (EDW) can accelerate the rate of change in mountain ecosystems, cryospheric systems, hydrological regimes and biodiversity. Here we review important mechanisms that contribute towards EDW: snow albedo and surface-based feedbacks; water vapour changes and latent heat release; surface water vapour and radiative flux changes; surface heat loss and temperature change; and aerosols. All lead to enhanced warming with elevation (or at a critical elevation), and it is believed that combinations of these mechanisms may account for contrasting regional patterns of EDW. We discuss future needs to increase knowledge of mountain temperature trends and their controlling mechanisms through improved observations, satellite-based remote sensing and model simulations.
1,628 citations
TL;DR: In this article, a systematic analysis reveals a steep decline in the costs of battery packs for electric vehicles, with market-leading manufacturers setting the pace with market leader Tesla and its suppliers.
Abstract: A systematic analysis reveals a steep decline in the costs of battery packs for electric vehicles, with market-leading manufacturers setting the pace.
1,578 citations
University of Florida1, University of Bonn2, Blaise Pascal University3, Institut national de la recherche agronomique4, Stanford University5, Prince of Songkla University6, Agricultural Research Service7, University of Arizona8, International Maize and Wheat Improvement Center9, Kansas State University10, International Water Management Institute11, Washington State University12, Michigan State University13, University of Leeds14, CGIAR15, Counterintelligence Field Activity16, Spanish National Research Council17, University of Tübingen18, University of Guelph19, Texas A&M University20, University of Maryland, College Park21, Aarhus University22, Potsdam Institute for Climate Impact Research23, Indian Agricultural Research Institute24, Goddard Institute for Space Studies25, Rothamsted Research26, University of Hohenheim27, Wageningen University and Research Centre28, Chinese Academy of Sciences29, Commonwealth Scientific and Industrial Research Organisation30, China Agricultural University31, Nanjing Agricultural University32
TL;DR: The authors systematically tested 30 different wheat crop models of the Agricultural Model Intercomparison and Improvement Project against field experiments in which growing season mean temperatures ranged from 15 degrees C to 32 degrees C, including experiments with artificial heating.
Abstract: Crop models are essential tools for assessing the threat of climate change to local and global food production(1). Present models used to predict wheat grain yield are highly uncertain when simulating how crops respond to temperature(2). Here we systematically tested 30 different wheat crop models of the Agricultural Model Intercomparison and Improvement Project against field experiments in which growing season mean temperatures ranged from 15 degrees C to 32 degrees C, including experiments with artificial heating. Many models simulated yields well, but were less accurate at higher temperatures. The model ensemble median was consistently more accurate in simulating the crop temperature response than any single model, regardless of the input information used. Extrapolating the model ensemble temperature response indicates that warming is already slowing yield gains at a majority of wheat-growing locations. Global wheat production is estimated to fall by 6% for each degrees C of further temperature increase and become more variable over space and time.
1,461 citations
TL;DR: The contribution of human-induced climate change to global heavy precipitation and hot extreme events is quantified in this paper, where the authors show that of the moderate extremes, 18% of precipitation and 75% of high-temperature events are attributable to warming.
Abstract: The contribution of human-induced climate change to global heavy precipitation and hot extreme events is quantified. The results show that of the moderate extremes, 18% of precipitation and 75% of high-temperature events are attributable to warming.
925 citations
International Union for Conservation of Nature and Natural Resources1, Sapienza University of Rome2, University of the Witwatersrand3, Microsoft4, University of Queensland5, Wildlife Conservation Society6, BirdLife International7, Norwegian Polar Institute8, James Cook University9, Conservation International10, Commonwealth Scientific and Industrial Research Organisation11, Stony Brook University12, Chinese Academy of Sciences13, Durham University14, National University of Singapore15, University of Melbourne16, Stellenbosch University17, Zoological Society of London18, University College London19, NatureServe20
TL;DR: In this article, three main approaches used to derive these currencies (correlative, mechanistic and trait-based) and their associated data requirements, spatial and temporal scales of application and modelling methods are described.
Abstract: The effects of climate change on biodiversity are increasingly well documented, and many methods have been developed to assess species' vulnerability to climatic changes, both ongoing and projected in the coming decades. To minimize global biodiversity losses, conservationists need to identify those species that are likely to be most vulnerable to the impacts of climate change. In this Review, we summarize different currencies used for assessing species' climate change vulnerability. We describe three main approaches used to derive these currencies (correlative, mechanistic and trait-based), and their associated data requirements, spatial and temporal scales of application and modelling methods. We identify strengths and weaknesses of the approaches and highlight the sources of uncertainty inherent in each method that limit projection reliability. Finally, we provide guidance for conservation practitioners in selecting the most appropriate approach(es) for their planning needs and highlight priority areas for further assessments.
808 citations
TL;DR: A survey of 119 countries showed that education is the strongest predictor of climate change awareness around the world as mentioned in this paper, which suggests that improving understanding of local impacts is vital for public engagement.
Abstract: A survey of 119 countries shows that education is the strongest predictor of climate change awareness around the world. The results suggest that improving understanding of local impacts is vital for public engagement.
760 citations
TL;DR: A new analysis shows that global warming could be limited to 1.5 °C by 2100, but that the window for achieving this is small and rapidly closing as mentioned in this paper, but this analysis does not consider the effects of human activities.
Abstract: A new analysis shows that global warming could be limited to 1.5 °C by 2100, but that the window for achieving this is small and rapidly closing.
757 citations
TL;DR: In this paper, the authors present multiple lines of evidence suggesting that this cooling may be due to a reduction in the AMOC over the twentieth century and particularly after 1970, and discuss a possible contribution of the melting of the Greenland Ice Sheet to the slowdown.
Abstract: Possible changes in Atlantic meridional overturning circulation (AMOC) provide a key source of uncertainty regarding future climate change. Maps of temperature trends over the twentieth century show a conspicuous region of cooling in the northern Atlantic. Here we present multiple lines of evidence suggesting that this cooling may be due to a reduction in the AMOC over the twentieth century and particularly after 1970. Since 1990 the AMOC seems to have partly recovered. This time evolution is consistently suggested by an AMOC index based on sea surface temperatures, by the hemispheric temperature difference, by coral-based proxies and by oceanic measurements. We discuss a possible contribution of the melting of the Greenland Ice Sheet to the slowdown. Using a multi-proxy temperature reconstruction for the AMOC index suggests that the AMOC weakness after 1975 is an unprecedented event in the past millennium (p > 0.99). Further melting of Greenland in the coming decades could contribute to further weakening of the AMOC.
717 citations
TL;DR: Research synthesizing the current state of knowledge about physiological plasticity in ectotherms shows that freshwater and marine animals seem to have a greater capacity for acclimation than terrestrial ones.
Abstract: Acclimation, a form of physiological plasticity, is the capacity for organisms to physiologically adjust to temperature variation. Such changes can potentially reduce climate change impacts on animal populations. Research synthesizing the current state of knowledge about physiological plasticity in ectotherms shows that freshwater and marine animals seem to have a greater capacity for acclimation than terrestrial ones.
641 citations
TL;DR: In this article, it was shown that oxalic acid (a common exudate) releases organic compounds from protective mineral associations, which can lead to loss of soil carbon.
Abstract: Climate change enhances root exudation of organic compounds into soils and can lead to loss of soil carbon. Research now shows that oxalic acid (a common exudate) releases organic compounds from protective mineral associations.
636 citations
Ocean University of China1, Commonwealth Scientific and Industrial Research Organisation2, University of New South Wales3, Hanyang University4, Yonsei University5, Georgia Institute of Technology6, University of Exeter7, University of Reading8, University of Paris9, Pohang University of Science and Technology10, National Oceanic and Atmospheric Administration11, Geophysical Fluid Dynamics Laboratory12, University of Tokyo13
TL;DR: A review of the state of knowledge on the El Nino/Southern Oscillation (ENSO), a natural climate phenomenon, can be found in this article, where the authors discuss recent advances and insights into how climate change will affect this natural climate varibility cycle.
Abstract: This Review looks at the state of knowledge on the El Nino/Southern Oscillation (ENSO), a natural climate phenomenon. It discusses recent advances and insights into how climate change will affect this natural climate varibility cycle. The El Nino/Southern Oscillation (ENSO) is the dominant climate phenomenon affecting extreme weather conditions worldwide. Its response to greenhouse warming has challenged scientists for decades, despite model agreement on projected changes in mean state. Recent studies have provided new insights into the elusive links between changes in ENSO and in the mean state of the Pacific climate. The projected slow-down in Walker circulation is expected to weaken equatorial Pacific Ocean currents, boosting the occurrences of eastward-propagating warm surface anomalies that characterize observed extreme El Nino events. Accelerated equatorial Pacific warming, particularly in the east, is expected to induce extreme rainfall in the eastern equatorial Pacific and extreme equatorward swings of the Pacific convergence zones, both of which are features of extreme El Nino. The frequency of extreme La Nina is also expected to increase in response to more extreme El Ninos, an accelerated maritime continent warming and surface-intensified ocean warming. ENSO-related catastrophic weather events are thus likely to occur more frequently with unabated greenhouse-gas emissions. But model biases and recent observed strengthening of the Walker circulation highlight the need for further testing as new models, observations and insights become available.
TL;DR: The authors suggest that it is more useful to regard the extreme circulation regime or weather event as being largely unaffected by climate change, and question whether known changes in the climate system's thermodynamic state affected the impact of a particular event.
Abstract: There is a tremendous desire to attribute causes to weather and climate events that is often challenging from a physical standpoint. Headlines attributing an event solely to either human-induced climate change or natural variability can be misleading when both are invariably in play. The conventional attribution framework struggles with dynamically driven extremes because of the small signal-to-noise ratios and often uncertain nature of the forced changes. Here, we suggest that a different framing is desirable, which asks why such extremes unfold the way they do. Specifically, we suggest that it is more useful to regard the extreme circulation regime or weather event as being largely unaffected by climate change, and question whether known changes in the climate system's thermodynamic state affected the impact of the particular event. Some examples briefly illustrated include 'snowmaggedon' in February 2010, superstorm Sandy in October 2012 and supertyphoon Haiyan in November 2013, and, in more detail, the Boulder floods of September 2013, all of which were influenced by high sea surface temperatures that had a discernible human component.
TL;DR: In this article, the authors provide a synthesis of the effects of tropical deforestation on climate and implications for agriculture, both in the tropics and worldwide, and suggest critical thresholds beyond which rainfall is substantially reduced.
Abstract: Tropical forests provide many ecosystem and climatic services. This Review provides a synthesis of the effects of tropical deforestation on climate and implications for agriculture, both in the tropics and worldwide. Tower, ground-based and satellite observations indicate that tropical deforestation results in warmer, drier conditions at the local scale. Understanding the regional or global impacts of deforestation on climate, and ultimately on agriculture, requires modelling. General circulation models show that completely deforesting the tropics could result in global warming equivalent to that caused by burning of fossil fuels since 1850, with more warming and considerable drying in the tropics. More realistic scenarios of deforestation yield less warming and less drying, suggesting critical thresholds beyond which rainfall is substantially reduced. In regional, mesoscale models that capture topography and vegetation-based discontinuities, small clearings can actually enhance rainfall. At this smaller scale as well, a critical deforestation threshold exists, beyond which rainfall declines. Future agricultural productivity in the tropics is at risk from a deforestation-induced increase in mean temperature and the associated heat extremes and from a decline in mean rainfall or rainfall frequency. Through teleconnections, negative impacts on agriculture could extend well beyond the tropics.
TL;DR: This article found that the recent warming in the Barents Sea has led to a change in spatial distribution of fish communities, with boreal communities expanding northwards at a pace reflecting the local climate velocities.
Abstract: Rapid warming of Arctic marine ecosystems has led to a change in the spatial distribution of fish communities, with boreal communities expanding into regions previously dominated by Arctic fish species, which are now retracting northwards. Arctic marine ecosystems are warming twice as fast as the global average1. As a consequence of warming, many incoming species experience increasing abundances and expanding distribution ranges in the Arctic2. The Arctic is expected to have the largest species turnover with regard to invading and locally extinct species, with a modelled invasion intensity of five times the global average3. Studies in this region might therefore give valuable insights into community-wide shifts of species driven by climate warming. We found that the recent warming in the Barents Sea4 has led to a change in spatial distribution of fish communities, with boreal communities expanding northwards at a pace reflecting the local climate velocities5. Increased abundance and distribution areas of large, migratory fish predators explain the observed community-wide distributional shifts. These shifts change the ecological interactions experienced by Arctic fish species. The Arctic shelf fish community retracted northwards to deeper areas bordering the deep polar basin. Depth might limit further retraction of some of the fish species in the Arctic shelf community. We conclude that climate warming is inducing structural change over large spatial scales at high latitudes, leading to a borealization of fish communities in the Arctic.
TL;DR: In this article, a hydraulic corollary to Darcy's law is used to predict the characteristics of plants that will survive during drought in a warmer climate, which indicates that forest trees will need to be shorter and more drought-tolerant to survive in the future.
Abstract: A hydraulic corollary to Darcy’s law is used to predict the characteristics of plants that will survive during drought in a warmer climate. This indicates that forest trees will need to be shorter and more drought-tolerant to survive in the future.
TL;DR: The co-occurrence of storm surge and heavy precipitation can compound coastal flooding, and the probability of such cooccurrences for the US has increased significantly over the past century as mentioned in this paper.
Abstract: The co-occurrence of storm surge and heavy precipitation can compound coastal flooding. Research now estimates the probability of such co-occurrences for the US and shows that the number of events has increased significantly over the past century.
TL;DR: Indonesian mangrove carbon stocks are estimated to be 1,083 ± 378 MgC ha−1 as mentioned in this paper, which is a large amount of carbon stored in mangroves.
Abstract: Indonesian mangrove carbon stocks are estimated to be 1,083 ± 378 MgC ha−1. In the past three decades Indonesia has lost 40% of its 2.9 Mha of mangroves; this is estimated to have resulted in annual CO2-equivalent emissions of 0.07–0.21 Pg. Mangroves provide a wide range of ecosystem services, including nutrient cycling, soil formation, wood production, fish spawning grounds, ecotourism and carbon (C) storage1. High rates of tree and plant growth, coupled with anaerobic, water-logged soils that slow decomposition, result in large long-term C storage. Given their global significance as large sinks of C, preventing mangrove loss would be an effective climate change adaptation and mitigation strategy. It has been reported that C stocks in the Indo-Pacific region contain on average 1,023 MgC ha−1 (ref. 2). Here, we estimate that Indonesian mangrove C stocks are 1,083 ± 378 MgC ha−1. Scaled up to the country-level mangrove extent of 2.9 Mha (ref. 3), Indonesia’s mangroves contained on average 3.14 PgC. In three decades Indonesia has lost 40% of its mangroves4, mainly as a result of aquaculture development5. This has resulted in annual emissions of 0.07–0.21 Pg CO2e. Annual mangrove deforestation in Indonesia is only 6% of its total forest loss6; however, if this were halted, total emissions would be reduced by an amount equal to 10–31% of estimated annual emissions from land-use sectors at present. Conservation of carbon-rich mangroves in the Indonesian archipelago should be a high-priority component of strategies to mitigate climate change.
University of Edinburgh1, University of Colorado Boulder2, National Ecological Observatory Network3, Woods Hole Oceanographic Institution4, University of Greifswald5, University of Copenhagen6, University of Alaska Fairbanks7, University of Vermont8, University of Oxford9, Norwegian University of Science and Technology10, Université du Québec11, Aarhus University12, University of Victoria13, St. John's University14, University of Bonn15, Adam Mickiewicz University in Poznań16, Texas A&M University17, Norwegian Polar Institute18, University of Zurich19, University of Basel20, University of Alberta21, Université de Sherbrooke22
TL;DR: In this article, the authors analyzed circumpolar data from 37 Arctic and alpine sites in 9 countries, including 25 species, and ∼42,000 annual growth records from 1,821 individuals, and demonstrated that the sensitivity of shrub growth to climate was heterogeneous, with European sites showing greater summer temperature sensitivity than North American sites, and higher at sites with greater soil moisture and for taller shrubs (for example, alders and willows) growing at their northern or upper elevational range edges.
Abstract: Rapid climate warming has been linked to increasing shrub dominance in the Arctic tundra. Research now shows that climate–shrub growth relationships vary spatially and according to site characteristics such as soil moisture and shrub height. Rapid climate warming in the tundra biome has been linked to increasing shrub dominance1,2,3,4. Shrub expansion can modify climate by altering surface albedo, energy and water balance, and permafrost2,5,6,7,8, yet the drivers of shrub growth remain poorly understood. Dendroecological data consisting of multi-decadal time series of annual shrub growth provide an underused resource to explore climate–growth relationships. Here, we analyse circumpolar data from 37 Arctic and alpine sites in 9 countries, including 25 species, and ∼42,000 annual growth records from 1,821 individuals. Our analyses demonstrate that the sensitivity of shrub growth to climate was: (1) heterogeneous, with European sites showing greater summer temperature sensitivity than North American sites, and (2) higher at sites with greater soil moisture and for taller shrubs (for example, alders and willows) growing at their northern or upper elevational range edges. Across latitude, climate sensitivity of growth was greatest at the boundary between the Low and High Arctic, where permafrost is thawing4 and most of the global permafrost soil carbon pool is stored9. The observed variation in climate–shrub growth relationships should be incorporated into Earth system models to improve future projections of climate change impacts across the tundra biome.
Commonwealth Scientific and Industrial Research Organisation1, Ocean University of China2, University of New South Wales3, Pacific Marine Environmental Laboratory4, University of Hawaii5, University of Exeter6, Geophysical Fluid Dynamics Laboratory7, Centre national de la recherche scientifique8, Monash University, Clayton campus9, University of Reading10
TL;DR: In this paper, an increase in frequency of La Nina events was predicted due to faster land warming relative to the ocean, and a greater chance of them occurring following extreme El Nino events.
Abstract: Extreme La Nina events occur when cold sea surface temperatures across the central Pacific Ocean create a strong temperature gradient to the Maritime continent in the west. This work projects an increase in frequency of La Nina events due to faster land warming relative to the ocean, and a greater chance of them occurring following extreme El Nino events. The El Nino/Southern Oscillation is Earth’s most prominent source of interannual climate variability, alternating irregularly between El Nino and La Nina, and resulting in global disruption of weather patterns, ecosystems, fisheries and agriculture1,2,3,4,5. The 1998–1999 extreme La Nina event that followed the 1997–1998 extreme El Nino event6 switched extreme El Nino-induced severe droughts to devastating floods in western Pacific countries, and vice versa in the southwestern United States4,7. During extreme La Nina events, cold sea surface conditions develop in the central Pacific8,9, creating an enhanced temperature gradient from the Maritime continent to the central Pacific. Recent studies have revealed robust changes in El Nino characteristics in response to simulated future greenhouse warming10,11,12, but how La Nina will change remains unclear. Here we present climate modelling evidence, from simulations conducted for the Coupled Model Intercomparison Project phase 5 (ref. 13), for a near doubling in the frequency of future extreme La Nina events, from one in every 23 years to one in every 13 years. This occurs because projected faster mean warming of the Maritime continent than the central Pacific, enhanced upper ocean vertical temperature gradients, and increased frequency of extreme El Nino events are conducive to development of the extreme La Nina events. Approximately 75% of the increase occurs in years following extreme El Nino events, thus projecting more frequent swings between opposite extremes from one year to the next.
TL;DR: The authors used passive microwave observations to provide global estimates for forest and non-forest biomass trends over the past two decades and found that vegetation change is a key component of the carbon cycle, but quantifying these changes is challenging.
Abstract: Vegetation change is a key component of the carbon cycle, but quantifying these changes is challenging. Research using passive microwave observations now provides global estimates for forest and non-forest biomass trends over the past two decades.
TL;DR: A study of public opinion in the United States revealed substantial variation across the nation as discussed by the authors on climate change action, and public support for climate change requires public action on the ground truth.
Abstract: Action on climate change requires public support. A study of public opinion in the United States reveals substantial variation across the nation.
TL;DR: The authors modifies a standard integrated assessment model to allow climate change to directly affect gross GDP growth rates, showing that climate change significantly slows down GDP growth in poor regions but not in rich countries, with implications for the level of near-term mitigation.
Abstract: Integrated assessment models estimate the impact of climate change on current economic output, but not on its rate of growth. This study modifies a standard integrated assessment model to allow climate change to directly affect gross GDP growth rates. Results show that climate change significantly slows down GDP growth in poor regions but not in rich countries, with implications for the level of near-term mitigation.
TL;DR: This article used observation and model data to show that human influence is increasing the probability of extremely hot summers in Europe, with events now expected to occur twice a decade, compared with predictions of twice a century in the early 2000s.
Abstract: In 2003, Europe experienced a summer heatwave that resulted in tens of thousands of deaths. This study uses observation and model data to show that human influence is increasing the probability of extremely hot summers in Europe, with events now expected to occur twice a decade, compared with predictions of twice a century in the early 2000s.
TL;DR: Despite the "pause" in surface warming, results from the global Argo program (2006-present) show that the heat content of the oceans is increasing as mentioned in this paper, despite the lack of surface warming.
Abstract: Despite the ‘pause’ in surface warming, results from the global Argo programme (2006–present) show that the heat content of the oceans is increasing.
TL;DR: In this article, the authors argue that psychological research should inform efforts to address climate change, to avoid misunderstandings about human behaviour and motivations that can lead to ineffective or misguided policies, and suggest important directions for further research.
Abstract: Human behaviour is integral not only to causing global climate change but also to responding and adapting to it. Here, we argue that psychological research should inform efforts to address climate change, to avoid misunderstandings about human behaviour and motivations that can lead to ineffective or misguided policies. We review three key research areas: describing human perceptions of climate change; understanding and changing individual and household behaviour that drives climate change; and examining the human impacts of climate change and adaptation responses. Although much has been learned in these areas, we suggest important directions for further research.
TL;DR: In this paper, the authors look at observations from the central USA and report that there has been an increase in the frequency of flooding, but little evidence for larger flood peaks, while climate models predict an increase of intense rainfall events due to a warmer atmosphere retaining more moisture.
Abstract: Climate models predict an increase in intense rainfall events due to a warmer atmosphere retaining more moisture. This study looks at observations from the central USA and reports that there has been an increase in the frequency of flooding, but little evidence for larger flood peaks.
TL;DR: The international climate regime represented by the United Nations Framework Convention on Climate Change (UNFCC) has been widely critiqued as mentioned in this paper, and new dynamic forms of climate governing are appearing in alternative domains, producing a more polycentric pattern.
Abstract: The international climate regime represented by the United Nations Framework Convention on Climate Change has been widely critiqued. However, 'new' dynamic forms of climate governing are appearing in alternative domains, producing a more polycentric pattern. Some analysts believe that the new forms will fill gaps in the existing regime, but this optimism is based on untested assumptions about their diffusion and performance. The advent of polycentric governance offers new opportunities for climate action, but it is too early to judge whether hopes about the effectiveness of emerging forms of climate governance are well founded.
Macquarie University1, University of Western Sydney2, Imperial College London3, University of Technology, Sydney4, University of Lleida5, Commonwealth Scientific and Industrial Research Organisation6, University of Antwerp7, University of Gothenburg8, Swedish University of Agricultural Sciences9, Lund University10, James Cook University11, Kansas State University12, Colorado State University13, University of Paris-Sud14, Brookhaven National Laboratory15, Oak Ridge National Laboratory16, Tuscia University17, Tohoku University18, Kyoto University19, University of Exeter20, Institut national de la recherche agronomique21, International Sleep Products Association22, University of Melbourne23, University of Auckland24, Spanish National Research Council25, University of Edinburgh26, Charles Darwin University27, Forestry Commission28, Ishikawa Prefectural University29, University of Helsinki30, Obihiro University of Agriculture and Veterinary Medicine31, University of New Mexico32, Federal University of Pará33, Technical University of Denmark34, University of Oxford35, Pontifical Catholic University of Peru36, Northeast Normal University37
TL;DR: In this paper, the authors present a database of globally distributed stomatal conductance (g(s) obtained in the field for a wide range of plant functional types (PFTs) and biomes.
Abstract: Stomatal conductance (g(s)) is a key land-surface attribute as it links transpiration, the dominant component of global land evapotranspiration, and photosynthesis, the driving force of the global carbon cycle. Despite the pivotal role of g(s) in predictions of global water and carbon cycle changes, a global-scale database and an associated globally applicable model of g(s) that allow predictions of stomatal behaviour are lacking. Here, we present a database of globally distributed g(s) obtained in the field for a wide range of plant functional types (PFTs) and biomes. We find that stomatal behaviour differs among PFTs according to their marginal carbon cost of water use, as predicted by the theory underpinning the optimal stomatal model(1) and the leaf and wood economics spectrum(2,3). We also demonstrate a global relationship with climate. These findin g(s) provide a robust theoretical framework for understanding and predicting the behaviour of g(s) across biomes and across PFTs that can be applied to regional, continental and global-scale modelling of ecosystem productivity, energy balance and ecohydrological processes in a future changing climate.
TL;DR: Saturation state is shown to be the key component of marine carbonate chemistry affecting larval shell development and growth in two commercially important bivalve species.
Abstract: Saturation state is shown to be the key component of marine carbonate chemistry affecting larval shell development and growth in two commercially important bivalve species.
TL;DR: In this paper, a spatially explicit assessment of pan-tropical wood fuel supply and demand is presented to estimate where harvest exceeds regrowth and the resultant GHG emissions for 2009.
Abstract: Over half of all wood harvested worldwide is used as fuel, supplying ∼9% of global primary energy. By depleting stocks of woody biomass, unsustainable harvesting can contribute to forest degradation, deforestation and climate change. However, past efforts to quantify woodfuel sustainability failed to provide credible results. We present a spatially explicit assessment of pan-tropical woodfuel supply and demand, calculate the degree to which woodfuel demand exceeds regrowth, and estimate woodfuel-related greenhouse-gas emissions for the year 2009. We estimate 27–34% of woodfuel harvested was unsustainable, with large geographic variations. Our estimates are lower than estimates from carbon offset projects, which are probably overstating the climate benefits of improved stoves. Approximately 275 million people live in woodfuel depletion ‘hotspots’—concentrated in South Asia and East Africa—where most demand is unsustainable. Emissions from woodfuels are 1.0–1.2 Gt CO2e yr−1 (1.9–2.3% of global emissions). Successful deployment and utilization of 100 million improved stoves could reduce this by 11–17%. At US$11 per tCO2e, these reductions would be worth over US$1 billion yr−1 in avoided greenhouse-gas emissions if black carbon were integrated into carbon markets. By identifying potential areas of woodfuel-driven degradation or deforestation, we inform the ongoing discussion about REDD-based approaches to climate change mitigation. Over half of the wood harvested globally is used as fuel. Unsustainable harvesting can deplete woody biomass, contributing to forest degradation, deforestation and climate change. A spatially explicit assessment of pan-tropical woodfuel supply and demand is used to estimate where harvest exceeds regrowth and the resultant GHG emissions for 2009.