Communications Earth & Environment最新文献

In tropical montane forests, the Earth's largest biodiversity hotspots, there is increasing evidence that climate warming is resulting in montane species being displaced by their lowland counterparts. However, the drivers of these changes are poorly understood. Across a large elevation gradient in the Colombian Andes, we established three experimental plantations of 15 dominant tree species including both naturally occurring montane and lowland species and measured their survival and growth. Here we show that 55% of the studied montane species maintained growth at their survival's hottest temperature with the remaining 45% being intolerant to such levels of warming, declining their growth, while lowland species benefited strongly from the warmest temperatures. Our findings suggest that the direct negative effects of warming and increased competition of montane species with lowland species are promoting increased homogeneity in community composition, resulting in reduced biodiversity.

The capacity of mangroves to reduce coastal flood risk resulted in legislation for mandatory widths of mangrove greenbelts in several countries with mangrove presence. Prescribed forest widths vary between 50 and 200 m. Here, we performed 216,000 numerical model runs informed by realistic conditions to quantify confidence in wave reduction capacity of mangroves for wind and swell waves. This analysis highlights that tidal flat areas fronting mangrove forests already account for 70% of reduction in wave heights. Within mangrove forests that are below 500 m wide, wave dissipation is strongly dependent on local water levels, wave characteristics and forest density. For forest widths of over 500 m, which constitute 46% of global coastal mangroves, around 75% or more of the incoming wave energy is dissipated. Hence, for relying on mangroves to dampen shorter waves, a new standard should be adopted that strives for mangrove widths of 500 m or more.

Over recent decades the Amazon region has been exposed to large-scale land-use changes and global warming. How these changes affect Amazonia's hydrological cycle remains unclear as meteorological data are scarce. We use tree ring oxygen isotope records to confirm that the Amazon hydrological cycle has intensified since 1980. Diverging isotopic trends from terra firme and floodplain trees from distinct sites (approximately 1000 km apart) in Western Amazon indicate rainfall amounts increased during the wet season and decreased during the dry season at large-scale. Using the Rayleigh distillation model, we estimate that wet season rainfall increased by 15-22%, and dry season rainfall decreased by 8-13%. These diverging trends provide evidence, independent from existing climate records, that the seasonality of the hydrological cycle in the Amazon is increasing. Continuation of the observed trends will have a pervasive impact on Amazon forests and floodplain ecosystems, and strongly affect the livelihoods of the regional riverine communities.

Debris flows are one of the most damaging natural hazards in mountainous terrain. Their dynamics are controlled by both surging behaviour and the influence of large boulders. However, a lack of high-resolution field measurements has limited our mechanistic understanding of these important processes. Here, we provide high-resolution in situ debris-flow surge measurements that demonstrate that surges are formed by the spontaneous growth of small surface instabilities into large waves, which amplify the destructiveness of the flow by increasing peak discharge. We use our field measurements to invert for the effective basal friction experienced by the flow, and support this reconstruction using numerical simulations that reproduce the formation and propagation of the surges. Detailed analysis of the inverted frictional data further shows that large boulders in the flow can influence local flow dynamics by increasing basal resistance, but this is not required to drive the surge wave instability. Our analysis provides new insights into debris-flow dynamics and can provide the foundation for improved hazard management of these damaging processes.

Climate change has increased forest fire extent in temperate and boreal North America. Here, we quantified the contribution of anthropogenic climate change to human mortality and economic burden from exposure to wildfire particulate matter at the county and state level across the contiguous US (2006 to 2020) by integrating climate projections, climate-wildfire models, wildfire smoke models, and emission and health impact modeling. Climate change contributed to approximately 15,000 wildfire particulate matter deaths over 15 years with interannual variability ranging from 130 (95% confidence interval: 64, 190) to 5100 (95% confidence interval: 2500, 7500) deaths and a cumulative economic burden of $160 billion. Approximately 34% of the additional deaths attributable to climate change occurred in 2020, costing $58 billion. The economic burden was highest in California, Oregon, and Washington. We suggest that absent abrupt changes in climate trajectories, land management, and population, the indirect impacts of climate change on human-health through wildfire smoke will escalate.

Extreme stratospheric events, such as sudden stratospheric warmings or strong polar vortex events, can have a persistent influence on winter surface weather. While these changes often lead to shifts in extratropical cyclone tracks and increased risk of extreme winds, flooding, or heavy snowfall, there has been no systematic effort to quantify their associated impacts with respect to stratospheric forcing. Here we establish the connection between stratospheric extreme events and midlatitude storms in the Euro-Atlantic region using reanalysis of the European Centre for Medium-Range Weather Forecasts and impact datasets. We show that storm-related hazards in northern Europe occur more frequently following strong vortex events than after sudden stratospheric warmings. Moreover, stratospheric forcing shapes the geographic pattern of storm impacts. Quantifying these connections - from precursors to hazards and impacts - can enable earlier warnings for society and for decision-makers in sectors such as emergency preparedness, public health, energy, and water management.

Conspiracy theories on COVID-19 mRNA vaccines and solar geoengineering (chemtrails) tend to reinforce one another, thereby posing significant challenges to public policy and scientific norms and generating confusion by conflating disparate issues. This paper is based on ongoing ethnographic fieldwork conducted in the United States, Germany, Switzerland, and France since 2015 in these two areas of active conspiracy attention, involving observation of social media pages and blogs, active participation in gatherings, and semi-structured interviews. Here, I adopt a diplomatic perspective, highlighting the reciprocal suspicion between science policy and conspiratorial thinking in a competition between two sets of connections of scientific facts, values, politics, fears, and hopes. The present study suggests that the contamination of the scientific discourse by seemingly unrelated claims in conspiracy theories offers fruitful insights to science communication into how publics make sense of science and technology in the fierce debates surrounding immunization and climate policy.

Sedimentary volcanism, whereby material is brought to the surface by fluid overpressure, has been proposed to explain some of the periglacial landforms, including pitted cones, in the Northern Plains of Mars. However, in the absence of convincing mineralogical evidence, the origin for these deposits has never been conclusively determined. Here we conduct a remote sensing-based mineralogical survey to identify hydrated minerals within the Thumbprint Terrains and neighbouring Vastitas Borealis Formation. We detect several occurrences of hydrated silica along with sulfate salts in candidate mud volcano-like morphologies which likely formed during the Early Amazonian period, supporting the sedimentary volcanism origin. Buoyancy-driven analytical modelling suggests the hydrated silica and sulfate salts are sourced from reservoirs at depths of several 10 s and 100 s of metres, respectively below the Thumbprint Terrains and Vastitas Borealis Formation. The exposed sulfates may have been derived from ancient buried evaporite deposits suggesting, at least locally, a salt-rich aqueous origin for the Vastitas Borealis Formation, and would be consistent with the presence of a past northern ocean on Mars.

The Russian invasion of Ukraine has disrupted crop exports and global food security, overshadowing critical nutrient asymmetry and the associated environmental risks. Here we demonstrate that following nutrient shortages after independence in 1991, fertilizer use increased over 2000-2021, but has decreased sharply following the invasion in early 2022. Input-output balances of nitrogen (N), phosphorus (P) and potassium (K) for staple crops (wheat, maize and sunflower) highlight soil P and K mining since 1991, increasing N surpluses during 2000-2021 and large NPK deficits since the war began in 2022. Based on analysis of five scenarios for 2030, we show how an Integrated Nutrient Management Plan for Ukraine combining manure recycling, precision fertilization and legume expansion is urgently needed, and would maintain crop productivity, significantly reduce nutrient surpluses and improve nutrient use efficiencies up to 80-89%, substantially curtailing environmental pollution and soil degradation.

The eruption of Hunga volcano on 15 January 2022 was an exceptional event in the satellite era. Record-breaking heights of the volcanic plume were reported, a large amount of water was injected into the stratosphere and a broad spectrum of atmospheric waves were detected. Here, we use satellite measurements to show that a transient ring of small ice particles (~2 μm) formed around the plume. We hypothesize that the ice ring was generated by the passage of an atmospheric wave triggered by a pressure pulse at the surface corresponding to a violent explosion that occurred during the 15 January 2022 eruption sequence. The passage of the atmospheric wave produced a transient rarefaction in the upper troposphere-lower stratosphere, which in turn led to oscillations in ambient temperature. Due to the supersaturated state of the atmosphere with respect to ice, ice particles formed in the wake of the radially propagating atmospheric wave, allowing an exceptional opportunity to study ice particle growth via vapour deposition. This atmospheric phenomenon serves as an important natural experiment that reveals the time scale on which ice particles nucleate and grow given an abrupt perturbation in ambient temperature.