| 1. |
- Abrams, Jesse F., et al.
(författare)
-
Committed Global Warming Risks Triggering Multiple Climate Tipping Points
- 2023
-
Ingår i: Earth's Future. - 2328-4277. ; 11:11
-
Tidskriftsartikel (refereegranskat)abstract
- Many scenarios for limiting global warming to 1.5(degrees)C assume planetary-scale carbon dioxide removal sufficient to exceed anthropogenic emissions, resulting in radiative forcing falling and temperatures stabilizing. However, such removal technology may prove unfeasible for technical, environmental, political, or economic reasons, resulting in continuing greenhouse gas emissions from hard-to-mitigate sectors. This may lead to constant concentration scenarios, where net anthropogenic emissions remain non-zero but small, and are roughly balanced by natural carbon sinks. Such a situation would keep atmospheric radiative forcing roughly constant. Fixed radiative forcing creates an equilibrium committed warming, captured in the concept of equilibrium climate sensitivity. This scenario is rarely analyzed as a potential extension to transient climate scenarios. Here, we aim to understand the planetary response to such fixed concentration commitments, with an emphasis on assessing the resulting likelihood of exceeding temperature thresholds that trigger climate tipping points. We explore transients followed by respective equilibrium committed warming initiated under low to high emission scenarios. We find that the likelihood of crossing the 1.5(degrees)C threshold and the 2.0(degrees)C threshold is 83% and 55%, respectively, if today's radiative forcing is maintained until achieving equilibrium global warming. Under the scenario that best matches current national commitments (RCP4.5), we estimate that in the transient stage, two tipping points will be crossed. If radiative forcing is then held fixed after the year 2100, a further six tipping point thresholds are crossed. Achieving a trajectory similar to RCP2.6 requires reaching net-zero emissions rapidly, which would greatly reduce the likelihood of tipping events.
|
|
| 2. |
- Ahlström, Anders, et al.
(författare)
-
Widespread Unquantified Conversion of Old Boreal Forests to Plantations
- 2022
-
Ingår i: Earth's Future. - : John Wiley & Sons. - 2328-4277. ; 10:11
-
Tidskriftsartikel (refereegranskat)abstract
- Across the boreal biome, clear-cutting of old, previously non clear-cut forests with high naturalness followed by tree planting or seeding is a major land use change. However, how much previously uncut forest has been converted to plantations remains unquantified. We combine Swedish national databases on clear-cuts and forest inventories to show that at least 19% of all clear-cuts since 2003 have occurred in old forests that were most likely not previously cut and planted or seeded. Old forests have been cut and lost at a steady rate of ∼1.4% per year for the same period, and at this rate they will disappear by the 2070s. There is further evidence that this type of unreported forest conversion is occurring across much of the world's boreal forest.
|
|
| 3. |
- Azar, Christian, 1969, et al.
(författare)
-
DICE and the Carbon Budget for Ambitious Climate Targets
- 2021
-
Ingår i: Earth's Future. - 2328-4277. ; 9:7
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The Dynamic Integrated Climate-Economy (DICE) model is one of the most influential Integrated Assessment Models available. Its founder Professor William Nordhaus was recently awarded Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel due to his pioneering work on the economics of climate change. In a recent paper in American Economic Journal: Economic Policy, Nordhaus uses the model to conclude that a 2.5°C target is almost out of reach. In this paper, we update DICE 2016 R2 with state-of-the-art models of the carbon cycle, heat uptake into the oceans, and the role of non-CO2 forcers. We find that the allowable remaining carbon budget (over the period 2015–2100) to meet a 2.5°C target to be 2,360 GtCO2 whereas the estimate obtained using DICE 2016 R2 is about 460 GtCO2. Nordhaus's estimate of the remaining carbon budget for this target is hence five times lower than estimates made by our updated DICE. We also compare our results with estimates by the Intergovernmental Panel on Climate Change (IPCC), and find our results to be in line with the carbon budgets presented in IPCC SR 1.5. We explain the reasons behind the difference between our result and that of Nordhaus and propose that an updated climate module in DICE is warranted.
|
|
| 4. |
- Borgomeo, E., et al.
(författare)
-
Tackling the Trickle: Ensuring Sustainable Water Management in the Arab Region
- 2020
-
Ingår i: Earth's Future. - 2328-4277. ; 8:5
-
Forskningsöversikt (refereegranskat)abstract
- Water scarcity in the Arab region is intensifying due to population growth, economic development, and the impacts of climate change. It is manifested in groundwater depletion, freshwater ecosystem degradation, deteriorating water quality, low levels of water storage per capita, and added pressures on transboundary water resources. High-income Arab countries have sought to circumvent the ever-present challenges of water scarcity through agricultural imports (virtual water trade), desalination, and, increasingly, wastewater reuse. In this review article, we argue that the narrative of water scarcity and supply-side technological fixes masks more systemic issues that threaten sustainable water management, including underperforming water utilities, protracted armed conflict and displacement, agricultural policies aimed at self-sufficiency, evolving food consumption behaviors, the future of energy markets, and educational policy. Water management challenges, particularly on the demand side, and responses in the Arab region cannot be understood in isolation from these broader regional and international political and socioeconomic trends. Recognizing the complex and interdependent challenges of water management is the first step in reforming approaches and shifting to more sustainable development outcomes and stability in the Arab region and beyond. ©2020 The Authors.
|
|
| 5. |
- Borja, Sonia, et al.
(författare)
-
Global Wetting by Seasonal Surface Water Over the Last Decades
- 2020
-
Ingår i: Earth's future. - : John Wiley and Sons Inc. - 2328-4277. ; 8:3
-
Tidskriftsartikel (refereegranskat)abstract
- Surface water bodies and their changes in the landscape are critical for societies and ecosystems. However, the global change in surface water area over the last decades remains unclear, as recent studies using the same satellite data disagree on its direction. Here, we reanalyze reported maps of global water classification based on that data in order to estimate the changes in long-term average surface water area from the first (1985-2000) to the second (2001-2015) half of the recent 30-year period (1985-2015). We find a net gain in global surface water area by 100,454 km(2), primarily due to seasonal water gains (83,329 km(2)). Over the world, we identify net wetting in 187 and net drying in 57 regional hydrological catchments, with the greatest water gain in Sabarmati (India) and loss in Amu Darya (Uzbekistan). We provide an interactive map to further explore the highly heterogeneous local changes around the world.
|
|
| 6. |
- Boysen, Lena R., et al.
(författare)
-
The limits to global-warming mitigation by terrestrial carbon removal
- 2017
-
Ingår i: Earth's Future. - 2328-4277. ; 5:5, s. 463-474
-
Tidskriftsartikel (refereegranskat)abstract
- Massive near-term greenhouse gas emissions reduction is a precondition for staying well below 2 degrees C global warming as envisaged by the Paris Agreement. Furthermore, extensive terrestrial carbon dioxide removal (tCDR) through managed biomass growth and subsequent carbon capture and storage is required to avoid temperature overshoot in most pertinent scenarios. Here, we address two major issues: First, we calculate the extent of tCDR required to repair delayed or insufficient emissions reduction policies unable to prevent global mean temperature rise of 2.5 degrees C or even 4.5 degrees C above pre-industrial level. Our results show that those tCDR measures are unable to counteract business-as-usual emissions without eliminating virtually all natural ecosystems. Even if considerable (Representative Concentration Pathway 4.5 [RCP4.5]) emissions reductions are assumed, tCDR with 50% storage efficiency requires >1.1 Gha of the most productive agricultural areas or the elimination of > 50% of natural forests. In addition, > 100 MtN/yr fertilizers would be needed to remove the roughly 320 GtC foreseen in these scenarios. Such interventions would severely compromise food production and/or biosphere functioning. Second, we reanalyze the requirements for achieving the 160-190 GtC tCDR that would complement strong mitigation action (RCP2.6) in order to avoid 2 degrees C overshoot anytime. We find that a combination of high irrigation water input and/or more efficient conversion to stored carbon is necessary. In the face of severe trade-offs with society and the biosphere, we conclude that large-scale tCDR is not a viable alternative to aggressive emissions reduction. However, we argue that tCDR might serve as a valuable supporting actor for strong mitigation if sustainable schemes are established immediately. Plain Language Summary In 2015, parties agreed to limit global warming to well below 2 degrees C above pre-industrial levels. However, this requires not only massive near-term greenhouse gas emissions reductions but also the application of negative emission techniques that extract already emitted carbon dioxide from the atmosphere. Specifically, this could refer to the establishment of extensive plantations of fast-growing tree and grass species in combination with biomass conversion to carbon-saving products. Although such deployment is seen as promising, its carbon sequestration potentials and possible side-effects still remain to be studied in depth. In this study, we analyzed two feasibility aspects of such a negative emissions approach using biomass plantations and carbon utilization pathways. First, we show that biomass plantations with subsequent carbon immobilization are likely unable to repair insufficient emission reduction policies without compromising food production and biosphere functioning due to its space-consuming properties. Second, the requirements for a strong mitigation scenario staying below the 2 degrees C target would require a combination of high irrigation water input and development of highly effective carbon process chains. Although we find that this strategy of sequestering carbon is not a viable alternative to aggressive emission reductions, it could still support mitigation efforts if sustainably managed.
|
|
| 7. |
- Brimicombe, Chloe, et al.
(författare)
-
Borderless Heat Hazards With Bordered Impacts
- 2021
-
Ingår i: Earth's Future. - : American Geophysical Union (AGU). - 2328-4277. ; 9:9
-
Tidskriftsartikel (refereegranskat)abstract
- Heatwaves are increasing in frequency, duration, and intensity due to climate change. They are associated with high mortality rates and cross-sectional impacts including a reduction in crop yield and power outages. Here we demonstrate that there are large deficiencies in reporting of heatwave impacts in international disasters databases, international organization reports, and climate bulletins. We characterize the distribution of heat stress across the world focusing on August in the Northern Hemisphere, when notably heatwaves have taken place (i.e., 2003, 2010, and 2020) for the last 20 years using the ERA5-HEAT reanalysis of the Universal Thermal Comfort Index and establish heat stress has grown larger in extent, more so during a heatwave. Comparison of heat stress against the emergency events impacts database and climate reports reveals underreporting of heatwave-related impacts. This work suggests an internationally agreed protocol should be put in place for impact reporting by organizations and national government, facilitating implementation of preparedness measures, and early warning systems.
|
|
| 8. |
- Bring, Arvid, et al.
(författare)
-
Contrasting Hydroclimatic Model-Data Agreements Over the Nordic-Arctic Region
- 2019
-
Ingår i: Earth's Future. - : John Wiley and Sons Inc. - 2328-4277. ; 7:12, s. 1270-1282
-
Tidskriftsartikel (refereegranskat)abstract
- Rapid changes in high-latitude hydroclimate have important implications for human societies and environment. Previous studies of different regions have indicated better agreement between climate model results and observation data for the thermodynamic variable of surface air temperature (T) than for the water variables of precipitation (P), evapotranspiration (ET), and runoff (R). Here we compare climate model output with observations for 64 Nordic and Arctic hydrological basins of different sizes, and for the whole region combined. We find an unexpectedly high agreement between models and observations for R, about as high as the model-observation agreement for T and distinctly higher than that for P or ET. Model-observation agreement for R and T is also consistently higher on the whole-region scale than individual basin scales. In contrast, model-observation agreement for P and ET is overall lower, and for some error measures also lower for the whole region than for individual basins of various scales. Region-specific soil freeze-thaw bias of climate models can at least partly explain the low model-observation agreement for P and ET, while leaving modeled R relatively unaffected. Thereby, model projections for this region may be similarly reliable and directly useful for large-scale average conditions of R as of T.
|
|
| 9. |
- Bring, Arvid, et al.
(författare)
-
Implications of freshwater flux data from the CMIP5 multimodel output across a set of Northern Hemisphere drainage basins
- 2015
-
Ingår i: EARTHS FUTURE. - 2328-4277. ; 3:6, s. 206-217
-
Tidskriftsartikel (refereegranskat)abstract
- The multimodel ensemble of the Coupled Model Intercomparison Project, Phase 5 (CMIP5) synthesizes the latest research in global climate modeling. The freshwater system on land, particularly runoff, has so far been of relatively low priority in global climate models, despite the societal and ecosystem importance of freshwater changes, and the science and policy needs for such model output on drainage basin scales. Here we investigate the implications of CMIP5 multimodel ensemble output data for the freshwater system across a set of drainage basins in the Northern Hemisphere. Results of individual models vary widely, with even ensemble mean results differing greatly from observations and implying unrealistic long-term systematic changes in water storage and level within entire basins. The CMIP5 projections of basin-scale freshwater fluxes differ considerably more from observations and among models for the warm temperate study basins than for the Arctic and cold temperate study basins. In general, the results call for concerted research efforts and model developments for improving the understanding and modeling of the freshwater system and its change drivers. Specifically, more attention to basin-scale water flux analyses should be a priority for climate model development, and an important focus for relevant model-based advice for adaptation to climate change.
|
|
| 10. |
- Bring, Arvid, et al.
(författare)
-
Pan-Arctic river discharge : Prioritizing monitoring of future climate change hot spots
- 2017
-
Ingår i: Earth's Future. - 2328-4277. ; 5:1, s. 72-92
-
Tidskriftsartikel (refereegranskat)abstract
- The Arctic freshwater cycle is changing rapidly, which will require adequate monitoring of river flows to detect, observe, and understand changes and provide adaptation information. There has, however, been little detail about where the greatest flow changes are projected, and where monitoring therefore may need to be strengthened. In this study, we used a set of recent climate model runs and an advanced macro-scale hydrological model to analyze how flows across the continental pan-Arctic are projected to change and where the climate models agree on significant changes. We also developed a method to identify where monitoring stations should be placed to observe these significant changes, and compared this set of suggested locations with the existing network of monitoring stations. Overall, our results reinforce earlier indications of large increases in flow over much of the Arctic, but we also identify some areas where projections agree on significant changes but disagree on the sign of change. For monitoring, central and eastern Siberia, Alaska, and central Canada are hot spots for the highest changes. To take advantage of existing networks, a number of stations across central Canada and western and central Siberia could form a prioritized set. Further development of model representation of high-latitude hydrology would improve confidence in the areas we identify here. Nevertheless, ongoing observation programs may consider these suggested locations in efforts to improve monitoring of the rapidly changing Arctic freshwater cycle.
|
|
| 11. |
- Ceola, S., et al.
(författare)
-
Drought and Human Mobility in Africa
- 2023
-
Ingår i: Earth's Future. - : American Geophysical Union (AGU). - 2328-4277. ; 11:12
-
Tidskriftsartikel (refereegranskat)abstract
- Human mobility from droughts is multifaceted and depends on environmental, political, social, demographic and economic factors. Although droughts cannot be considered as the single trigger, they significantly influence people's decision to move. Yet, the ways in which droughts influence patterns of human settlements have remained poorly understood. Here we explore the relationships between drought occurrences and changes in the spatial distribution of human settlements across 50 African countries for the period 1992-2013. For each country, we extract annual drought occurrences from two indicators, the international disaster database EM-DAT and the standardized precipitation evapotranspiration index (SPEI-12) records, and we evaluate human settlement patterns by considering urban population data and human distance to rivers, as derived from nighttime lights. We then compute human displacements as variations in human distribution between adjacent years, which are then associated with drought (or non-drought) years. Our results show that drought occurrences across Africa are often associated with (other things being equal) human mobility toward rivers or cities. In particular, we found that human settlements tend to get closer to water bodies or urban areas during drought conditions, as compared to non-drought periods, in 70%-81% of African countries. We interpret this tendency as a physical manifestation of drought adaptation, and discuss how this may result into increasing flood risk or overcrowding urban areas. As such, our results shed light on the interplay between human mobility and climate change, bolstering the analysis on the spatiotemporal dynamics of drought risks in a warming world. Prolonged water shortages induced by droughts can have severe consequences on both the environment and society. For instance, the mobility of people can be influenced by drought events. In order to test this assumption, we relate the movement of people to drought occurrences, without considering any additional factor. We focus on Africa, since it is one of the most drought-prone continents and the movement of people is more prominent compared to other areas. We find that people tend to move closer to rivers and to urban centers during droughts, as compared to non-drought periods. This pattern is found for the majority of African countries, which suggests a large-scale signal. The increased movement of people toward rivers during droughts might generate larger human losses if flood events take place in the future. A new methodology integrating satellite data is developed for evaluating drought-induced human displacements in AfricaWe found that 70%-81% of African countries exhibit larger displacements during droughts, as compared to non-drought periodsHuman displacement toward rivers and urban centers is triggered, other things being equal, by drought occurrences
|
|
| 12. |
- Colesie, Claudia
(författare)
-
The Longest Baseline Record of Vegetation Dynamics in Antarctica Reveals Acute Sensitivity to Water Availability
- 2022
-
Ingår i: Earth's Future. - 2328-4277. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Against a changing climate, the development of evidence-based and progressive conservation policies depends on robust and quantitative baseline studies to resolve habitat natural variability and rate of change. Despite Antarctica's significant role in global climate regulation, climate trend estimates for continental Antarctica are ambiguous due to sparse long-term in situ records. Here, we present the longest, spatially explicit survey of Antarctic vegetation by harmonizing historic vegetation mapping with modern remote sensing techniques. In 1961, E. D. Rudolph established a permanent survey plot at Cape Hallett, one of the most botanically diverse areas along the Ross Sea coastline, harboring all known types of non-vascular Antarctic vegetation. Following a survey in 2004 using ground-based photography, we conducted the third survey of Rudolph's Plot in 2018 using near-ground remote sensing and methodologies closely mirroring the two historic surveys to identify long-term changes and trends. Our results revealed that the vegetation at Cape Hallett remained stable over the past six decades with no evidence of transformation related to a changing climate. Instead, the local vegetation shows strong seasonal phenology, distribution patterns that are driven by water availability, and steady perennial growth of moss. Given that East Antarctica is at the tipping point of drastic change in the near future, with biological change having been reported at certain locations, this record represents a unique and potentially the last opportunity to establish a meaningful biological sentinel that will allow us to track subtle yet impactful environmental change in terrestrial Antarctica in the 21st century.
|
|
| 13. |
- Collentine, Dennis
(författare)
-
Land Policy for Flood Risk Management-Toward a New Working Paradigm
- 2022
-
Ingår i: Earth's Future. - 2328-4277. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Flood risk management (FRM) aims to integrate necessary technical measures with environmental and societal approaches. Focusing on the process and governance of how to plan, implement, and maintain solutions therefore becomes essential. Among the different stakeholders, landowners are a key group to be considered. This contribution elaborates on the interconnections between land policy, FRM and private land ownership. It is based on the European COST Action network LAND4FLOOD, which brings together academics and stakeholders from various disciplines and more than 35 countries. We argue for a less project oriented and more process oriented approach, a focus on land management and more emphasis on small-scale measures. This represents a break with some of the recent working paradigms of FRM.
|
|
| 14. |
- de Brito, Mariana Madruga, et al.
(författare)
-
Uncovering the Dynamics of Multi-Sector Impacts of Hydrological Extremes : A Methods Overview
- 2024
-
Ingår i: Earth's Future. - : American Geophysical Union (AGU). - 2328-4277. ; 12:1
-
Forskningsöversikt (refereegranskat)abstract
- Hydrological extremes, such as droughts and floods, can trigger a complex web of compound and cascading impacts (CCI) due to interdependencies between coupled natural and social systems. However, current decision-making processes typically only consider one impact and disaster event at a time, ignoring causal chains, feedback loops, and conditional dependencies between impacts. Analyses capturing these complex patterns across space and time are thus needed to inform effective adaptation planning. This perspective paper aims to bridge this critical gap by presenting methods for assessing the dynamics of the multi-sector CCI of hydrological extremes. We discuss existing challenges, good practices, and potential ways forward. Rather than pursuing a single methodological approach, we advocate for methodological pluralism. We see complementary or even convergent roles for analyses based on quantitative (e.g., data-mining, systems modeling) and qualitative methods (e.g., mental models, qualitative storylines). The data-driven and knowledge-driven methods provided here can serve as a useful starting point for understanding the dynamics of both high-frequency CCI and low-likelihood but high-impact CCI. With this perspective, we hope to foster research on CCI to improve the development of adaptation strategies for reducing the risk of hydrological extremes. Droughts and floods can have significant impacts on both natural and social systems. These impacts are often interconnected, resulting in a complex chain of events. In this perspective paper, we aim to assist researchers in understanding the dynamics of compound and cascading impacts (CCI) caused by hydrological extremes. We provide an overview of various methods that can be utilized to assess and analyze interconnected impacts. To begin, we address the ongoing challenges associated with CCI research, such as the limited availability of comprehensive impact data spanning multiple sectors and over extended periods. Subsequently, we present a range of qualitative and quantitative methods that can be employed to analyze CCI dynamics, supported by case study examples. Finally, we conclude with six recommendations to advance the research in this field. Systematic efforts to collect data on impacts across multiple sectors, systems, and years are requiredMethodological pluralism is necessary to fully address the complexity of compound and cascading impacts (CCI) and their underlying risk driversInvestigation of the risks of multi-sector impacts should be guided not only by probability but also by plausibility considerations
|
|
| 15. |
- Di Baldassarre, Giuliano, et al.
(författare)
-
An integrative research framework to unravel the interplay of natural hazards and vulnerabilities
- 2018
-
Ingår i: Earth's Future. - : John Wiley & Sons. - 2328-4277. ; 6:3, s. 305-310
-
Tidskriftsartikel (refereegranskat)abstract
- Climate change, globalization, urbanization, social isolation, and increased interconnectednessbetween physical, human, and technological systems pose major challenges to disaster risk reduction(DRR). Subsequently, economic losses caused by natural hazards are increasing in many regions of theworld, despite scientific progress, persistent policy action, and international cooperation. We argue thatthese dramatic figures call for novel scientific approaches and new types of data collection to integratethe two main approaches that still dominate the science underpinning DRR: the hazard paradigm and thevulnerability paradigm. Building from these two approaches, here we propose a research framework thatspecifies the scope of enquiry, concepts, and general relations among phenomena. We then discuss theessential steps to advance systematic empirical research and evidence-based DRR policy action.
|
|
| 16. |
- Ernakovich, J. G., et al.
(författare)
-
Is A Common Goal A False Hope in Convergence Research? : Opportunities and Challenges of International Convergence Research to Address Arctic Change
- 2021
-
Ingår i: Earth's Future. - : American Geophysical Union (AGU). - 2328-4277. ; 9:5
-
Tidskriftsartikel (refereegranskat)abstract
- The Arctic faces multiple pressures including climate change, shifting demographics, human health risks, social justice imbalances, governance issues, and expanding resource extraction. A convergence of academic disciplines—such as natural and social sciences, engineering and technology, health and medicine—and international perspectives is required to meaningfully contribute to solving the challenges of Arctic peoples and ecosystems. However, successfully carrying out convergent, international research and education remains a challenge. Here, lessons from the planning phase of a convergence research project concerned with the health of Arctic waters developed by the Arctic Science IntegrAtion Quest (ASIAQ) are discussed. We discuss our perspective on the challenges, as well as strategies for success, in convergence research as gained from the ASIAQ project which assembled an international consortium of researchers from disparate disciplines representing six universities from four countries (Sweden, Japan, Russia, and the United States) during 2018–2020.
|
|
| 17. |
- Fahrländer, Simon Felix, et al.
(författare)
-
Hydroclimatic Vulnerability of Wetlands to Upwind Land Use Changes
- 2024
-
Ingår i: Earth's Future. - 2328-4277. ; 12:3
-
Tidskriftsartikel (refereegranskat)abstract
- Despite their importance, wetland ecosystems protected by the Ramsar Convention are under pressure from climate change and human activities. These drivers are altering water availability in these wetlands, changing water levels or surface water extent, in some cases, beyond historical variability. Attribution of the effects of human and climate activities is usually focused on changes within the wetlands or their upstream surface and groundwater inputs. However, the reliance of wetland water availability on upwind atmospheric moisture supply is less understood. Here, we assess the vulnerability of 40 Ramsar wetlands to precipitation changes caused by land use and hydroclimatic change occurring in their upwind moisture-supplying regions. We use moisture flows from a Lagrangian tracking model, atmospheric reanalysis data, and historical land use change (LUC) data to assess and quantify these changes. Our analyses show that historical LUC has decreased precipitation and terrestrial moisture recycling in most wetland hydrological basins, decreasing surface water availability (precipitation minus evaporation). The most substantial effects on wetland water availability occurred in the tropic subtropical regions of Central Europe and Asia. Overall, we found wetlands in Central Asia and South America to be the most vulnerable by a combination of LUC-driven effects on runoff, high terrestrial precipitation recycling, and recent decreases in surface water availability. This study stresses the need to incorporate upwind effects of land use changes in the restoration, management, and conservation of the world's wetlands.
|
|
| 18. |
- Fang, Zhongxiang, et al.
(författare)
-
Globally Increasing Atmospheric Aridity Over the 21st Century
- 2022
-
Ingår i: Earth's Future. - 2328-4277. ; 10:10
-
Tidskriftsartikel (refereegranskat)abstract
- Vapor pressure deficit (VPD) is of great importance to control the land-atmosphere exchange of water and CO2. Here we use in situ observations to assess the performance of monthly VPD calculated from state-of-the-art data sets including CRU, ERA5, and Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA2). We investigate trends in VPD at global scale and for different climatic zones for 1981–2020 and future trends (2021–2100) from Coupled Model Inter-comparison Project phase 6 (CMIP6) outputs. The results show that monthly VPD estimated from CRU, ERA5, and MERRA2 correlated well against in situ estimates from 15,531 World Meteorological Organization stations, with R2 ranging between 0.92 and 0.96. Moreover, robust correlations were also found across in situ stations and when analyzing different months separately. During 1981–2020, VPD increased in all climatic zones, with the strongest increase in the arid zone, followed by tropical, temperate, cold and polar zones. CMIP6 simulations show a continuously increasing trend in VPD (0.028 hPa year−1), with the largest increase in the arid zone (0.063 hPa year−1). The magnitudes of trends are found to increase following the magnitude of CO2 increases in the future emission scenarios. We highlight that atmospheric aridification will continue under global warming, which may pose an increasing threat to terrestrial ecosystems and particularly dryland agricultural systems.
|
|
| 19. |
- Ferguson, Grant, et al.
(författare)
-
Acceleration of Deep Subsurface Fluid Fluxes in the Anthropocene
- 2024
-
Ingår i: Earth's Future. - : John Wiley & Sons. - 2328-4277. ; 12:4
-
Tidskriftsartikel (refereegranskat)abstract
- The Anthropocene has been framed around humanity's impact on atmospheric, biologic, and near-surface processes, such as land use and vegetation change, greenhouse gas emissions, and the above-ground hydrologic cycle. Groundwater extraction has lowered water tables in many key aquifers but comparatively little attention has been given to the impacts in the deeper subsurface. Here, we show that fluid fluxes from the extraction and injection of fluids associated with oil and gas production and inflow of water into mines likely exceed background flow rates in deep (>500 m) groundwater systems at a global scale. Projected carbon capture and sequestration (CCS), geothermal energy production, and lithium extraction to facilitate the energy transition will require fluid production rates exceeding current oil and co-produced water extraction. Natural analogs and geochemical modeling indicate that subsurface fluid manipulation in the Anthropocene will likely appear in the rock record. The magnitude and importance of these changes are unclear, due to a lack of understanding of how deep subsurface hydrologic and geochemical cycles and associated microbial life interact with the rest of the Earth system.
|
|
| 20. |
- Frieler, Katja, et al.
(författare)
-
Understanding the weather signal in national crop-yield variability
- 2017
-
Ingår i: Earth's Future. - 2328-4277. ; 5:6, s. 605-616
-
Tidskriftsartikel (refereegranskat)abstract
- Year-to-year variations in crop yields can have major impacts on the livelihoods of subsistence farmers and may trigger significant global price fluctuations, with severe consequences for people in developing countries. Fluctuations can be induced by weather conditions, management decisions, weeds, diseases, and pests. Although an explicit quantification and deeper understanding of weather-induced crop-yield variability is essential for adaptation strategies, so far it has only been addressed by empirical models. Here, we provide conservative estimates of the fraction of reported national yield variabilities that can be attributed to weather by state-of-the-art, process-based crop model simulations. We find that observed weather variations can explain more than 50% of the variability in wheat yields in Australia, Canada, Spain, Hungary, and Romania. For maize, weather sensitivities exceed 50% in seven countries, including the United States. The explained variance exceeds 50% for rice in Japan and South Korea and for soy in Argentina. Avoiding water stress by simulating yields assuming full irrigation shows that water limitation is a major driver of the observed variations in most of these countries. Identifying the mechanisms leading to crop-yield fluctuations is not only fundamental for dampening fluctuations, but is also important in the context of the debate on the attribution of loss and damage to climate change. Since process-based crop models not only account for weather influences on crop yields, but also provide options to represent human-management measures, they could become essential tools for differentiating these drivers, and for exploring options to reduce future yield fluctuations.
|
|
| 21. |
- Gong, Guoqing, et al.
(författare)
-
Anomalous Water Vapor Circulation in an Extreme Drought Event of the Mid-Reaches of the Lancang-Mekong River Basin
- 2024
-
Ingår i: EARTHS FUTURE. - 2328-4277. ; 12:8
-
Tidskriftsartikel (refereegranskat)abstract
- The middle reaches of the Lancang-Mekong River Basin (M-LMRB) experienced a record-breaking drought event in 2019, resulting in significant economic losses of approximately 650 million dollars and affecting a population of 17 million. However, the anomalous circulation and transportation processes of water vapor, which may have played a crucial role in inducing the extreme drought, have not been fully studied. In this study, we analyze the water vapor circulation during the 2019 drought event using the land-atmosphere water balance and a backward trajectory model for moisture tracking. Our results indicate that the precipitation in the M-LMRB from May to October 2019 was only 71.9% of the long-term climatological mean (1959-2021). The low precipitation during this drought event can be attributed to less-than-normal external water vapor supply. Specifically, the backward trajectory model reveals a decrease in the amount of water vapor transported from the Indian Ocean, the Bay of Bengal, and the Pacific Ocean, which are the main moisture sources for precipitation in the region. Comparing the atmospheric circulation patterns in 2019 with the climatology, we identify anomalous anticyclone conditions in the Bay of Bengal, anomalous westerlies in the Northeast Indian Ocean, and an anomalous cyclone in the Western Pacific Ocean, collectively facilitating a stronger export of water vapor from the region. Therefore, the dynamic processes played a more significant role than thermodynamic processes in contributing to the 2019 extreme drought event. In 2019, a record-breaking drought hit the M-LMRB, leading to significant economic losses and affecting a large population. This study explores the water vapor circulation during this drought using land-atmosphere water balance and a backward trajectory model. Findings show that precipitation from May to October 2019 was only seventy percent of the average from 1959 to 2021. The drought's severity was mainly due to a lack of water vapor from key sources: the Indian Ocean, the Bay of Bengal, and the Pacific Ocean. Anomalous weather patterns-an anticyclone in the Bay of Bengal, unusual westerlies in the Northeast Indian Ocean, and a cyclone in the Western Pacific-led to a significant reduction in water vapor reaching the region. This indicates that dynamic atmospheric processes played a larger role in causing the extreme drought than thermodynamic ones. These insights help improve understanding and prediction of droughts in Southeast Asia, particularly under changing climate conditions. Reduced external water vapor transport primarily leads to negative precipitation anomalies There has been a reduction in water vapor originating from the Indian Ocean, Bay of Bengal, and Pacific Ocean The reduction in water vapor transport is primarily influenced by dynamic factors rather than thermodynamic ones
|
|
| 22. |
- Gregor, Konstantin, et al.
(författare)
-
Trade-Offs for Climate-Smart Forestry in Europe Under Uncertain Future Climate
- 2022
-
Ingår i: Earth's Future. - 2328-4277. ; 10:9
-
Tidskriftsartikel (refereegranskat)abstract
- Forests mitigate climate change by storing carbon and reducing emissions via substitution effects of wood products. Additionally, they provide many other important ecosystem services (ESs), but are vulnerable to climate change; therefore, adaptation is necessary. Climate-smart forestry combines mitigation with adaptation, whilst facilitating the provision of many ESs. This is particularly challenging due to large uncertainties about future climate. Here, we combined ecosystem modeling with robust multi-criteria optimization to assess how the provision of various ESs (climate change mitigation, timber provision, local cooling, water availability, and biodiversity habitat) can be guaranteed under a broad range of climate futures across Europe. Our optimized portfolios contain 29% unmanaged forests, and implicate a successive conversion of 34% of coniferous to broad-leaved forests (11% vice versa). Coppices practically vanish from Southern Europe, mainly due to their high water requirement. We find the high shares of unmanaged forests necessary to keep European forests a carbon sink while broad-leaved and unmanaged forests contribute to local cooling through biogeophysical effects. Unmanaged forests also pose the largest benefit for biodiversity habitat. However, the increased shares of unmanaged and broad-leaved forests lead to reductions in harvests. This raises the question of how to meet increasing wood demands without transferring ecological impacts elsewhere or enhancing the dependence on more carbon-intensive industries. Furthermore, the mitigation potential of forests depends on assumptions about the decarbonization of other industries and is consequently crucially dependent on the emission scenario. Our findings highlight that trade-offs must be assessed when developing concrete strategies for climate-smart forestry.
|
|
| 23. |
- Guillaume, Joseph H. A., et al.
(författare)
-
Giving Legs to Handprint Thinking : Foundations for Evaluating the Good We Do
- 2020
-
Ingår i: Earth's Future. - 2328-4277. ; 8:6
-
Tidskriftsartikel (refereegranskat)abstract
- In environmental management and sustainability there is an increasing interest in measurement and accounting of beneficial impact-as an incentive to action, as a communication tool, and to move toward a positive, constructive approach focused on opportunities rather than problems. One approach uses the metaphor of a handprint, complementing the notion of environmental footprints, which have been widely adopted for impact measurement and accounting. We analyze this idea by establishing core principles of handprint thinking: Handprint encourages actions with positive impacts and connects to analyses of footprint reductions but adds value to them and addresses the issue of what action should be taken. We also identify five key questions that need to be addressed and decisions that need to be made in performing a (potentially quantitative) handprint assessment, related to scoping of the improvement to be made, how it is achieved, and how credit is assigned, taking into account constraints on action. A case study of the potential water footprint reduction of an average Finn demonstrates how handprint thinking can be a natural extension of footprint reduction analyses. We find that there is a diversity of possible handprint assessments that have the potential to encourage doing good. Their common foundation is handprint thinking.
|
|
| 24. |
- Gårdmark, Anna, et al.
(författare)
-
Temperature-Dependence Assumptions Drive Projected Responses of Diverse Size-Based Food Webs to Warming
- 2024
-
Ingår i: Earth's Future. - 2328-4277. ; 12
-
Tidskriftsartikel (refereegranskat)abstract
- Food web projections are critical for evaluating potential risks to ecosystems and fisheries under global warming. The temperature dependence of biological processes and regional differences in food web structure are two important sources of uncertainty and variation in climate forced projections of fish communities, but we do not know their magnitude or relative contribution. Here we systematically evaluated a range of different assumptions about temperature-dependence on rates, including size-dependent effects, controlling food intake, metabolism, and non-predation mortality in fishes using species-resolved size spectrum food web models that link individual-level physiological processes to population and community dynamics. We simulated the physiological effect of warming in a range of size-structured food web models calibrated to different marine ecosystems and in simplified trait-based models. Higher food intake in warmed conditions increased total fish biomass, catches, and mean body weight, but these effects were offset by the negative effects of warming on metabolism and mortality, which combined resulted in lower total biomasses and catches for most food webs. These effects were enhanced when warming increased metabolic rates more than food intake, and the outcomes were also sensitive to size dependency of temperature responses. Importantly, these general patterns were not uniform across all food webs-individual functional groups and fish species within food webs responded to warming in different ways depending on their position in the food web and its structure. Hence, caution is warranted when generalizing food web or species outcomes to warming because they are mediated by community interactions. Uncertainty related to temperature dependence and ecological interactions will impact food web projections and should be represented in climate change projections.Multi-species models are often used to predict how climate change will affect marine ecosystems, fisheries yields and conservation. However, temperature can affect species in a variety of ways, making predictions challenging. Moreover, warming driven changes in a fish community will also depend on species interactions, potentially amplifying or dampening warmingdriven effects in individual species. We explored how 2 degrees C of warming may impact fish biomasses, yields and sizes using six models developed for different marine food webs and three theoretical models with different assumptions about species interactions. We found that, overall, warming tended to result in lower biomasses and fisheries yields, but slightly larger average fish sizes. Yet, results differed depending on how we modeled temperature effects on species food intake and energy expenditure. Moreover, even under the same assumptions about temperature impacts, models developed for different ecosystems behaved differently showing that species interactions will modify warming effects, making general predictions difficult. To make better predictions on warming impacts and more informed adaptation strategies we urgently need more work to understand how temperature affects individual species and communities. Meanwhile, models predicting ecosystems responses to warming should more clearly account for the uncertainty in temperature effects on fishes.Assumptions regarding how temperature drives biological rates strongly influence food web responses to warming Community interactions further modify outcomes to warming which complicate efforts to generalize warming responses across food webs Uncertainty in food web temperature dependences should be represented in climate change projections
|
|
| 25. |
- Huss, M., et al.
(författare)
-
Toward mountains without permanent snow and ice
- 2017
-
Ingår i: Earth's Future. - 2328-4277. ; 5:5, s. 418-435
-
Forskningsöversikt (refereegranskat)abstract
- The cryosphere in mountain regions is rapidly declining, a trend that is expected to accelerate over the next several decades due to anthropogenic climate change. A cascade of effects will result, extending from mountains to lowlands with associated impacts on human livelihood, economy, and ecosystems. With rising air temperatures and increased radiative forcing, glaciers will become smaller and, in some cases, disappear, the area of frozen ground will diminish, the ratio of snow to rainfall will decrease, and the timing and magnitude of both maximum and minimum streamflow will change. These changes will affect erosion rates, sediment, and nutrient flux, and the biogeochemistry of rivers and proglacial lakes, all of which influence water quality, aquatic habitat, and biotic communities. Changes in the length of the growing season will allow low-elevation plants and animals to expand their ranges upward. Slope failures due to thawing alpine permafrost, and outburst floods from glacier-and moraine-dammed lakes will threaten downstream populations.Societies even well beyond the mountains depend on meltwater from glaciers and snow for drinking water supplies, irrigation, mining, hydropower, agriculture, and recreation. Here, we review and, where possible, quantify the impacts of anticipated climate change on the alpine cryosphere, hydrosphere, and biosphere, and consider the implications for adaptation to a future of mountains without permanent snow and ice.
|
|
