Communications Earth & Environment最新文献

Large-scale reforestation is a prominent proposed climate mitigation strategy, but its full temperature impact remains poorly understood. Here, we present a systematic comparison of temperature responses to three distinct reforestation potentials using a fully-coupled Earth System Model. We find that reforestation consistently provides net global cooling, ranging from -0.13^∘C to -0.25^∘C, due to carbon uptake partially offset by biogeophysical warming. Crucially, a comparable net global cooling can be achieved with substantially smaller (450 Mha less area) but strategically located reforestation. Reforestation locally cools the tropics but causes albedo-driven warming in higher latitudes, which is often amplified by non-local effects. The different reforestation patterns alone can induce a wide range of non-local effects, showing that planting locations shape the biogeophysical response through atmospheric and oceanic feedbacks. Our findings underscore the importance of climate-smart policies that focus on the geographical placement of reforestation, considering both biogeochemical and biogeophysical effects to maximize cooling benefits.

Campi Flegrei last erupted in 1538 and periods of increased seismicity, gas emission and ground deformation occurred in the 50's, 70's 80's and are ongoing since 2005. The eventual culmination of the unrest in an eruption, would directly impact on 2 million people living in the region, making it of critical concern for scientists, authorities and the public. Here, we use existing data, thermal modelling and calculations of the physical properties of magma, to provide plausible future scenarios, under the assumption that magma injection at 4-5 km depth is responsible for the unrest episodes recorded since 1950. Our calculations suggest that a critically pressurised reservoir containing potentially eruptible magma is present today at ~ 4 km depth. However, a major impediment to eruption is the reservoir volume, which would need 2-3 decades to grow to the size of the one that fed the last eruption of Campi Flegrei in 1538.

Ocean oxygen minimum zones have expanded since the mid-20^th century, yet their future remains uncertain. Previous studies show that the eastern tropical North Pacific was well oxygenated during the warm Miocene Climatic Optimum (17.0-14.8 Ma), suggesting better oxygenation under climatic warming. To explore whether this response was global, we reconstruct Miocene oxygenation in the second largest oxygen minimum zone, the Arabian Sea. Trace elements and nitrogen isotopes in planktonic foraminifera show that the Arabian Sea was also better oxygenated during the Miocene Climatic Optimum than today. However, deoxygenation history and establishment of a true oxygen deficient zone following the Miocene cooling lagged in the Arabian Sea, indicating the important role of regional oceanographic processes like proto-monsoon or Tethys outflow. Our study supports future projections of deoxygenation reversals in both oxygen minimum zones, but with more complexity in the Arabian Sea due to competing changes in monsoonal upwelling and influx from marginal seas.

Achieving just, equitable, and effective sustainability transformations requires diverse social engagement. This paper identifies five key roles played by Indigenous Peoples and local communities as agents of transformative change: embodying sustainable lifeways, resisting harm and defending rights, extending their practices to influence broader systems, and offering foundational models for care-oriented economies and governance. Through illustrative examples, we show how Indigenous Peoples and local communities actively contribute to global transformation. We emphasize the importance of engaging with a wide range of actors in supporting, expanding, and deepening these contributions to realize meaningful, systemic change toward a sustainable and just future.

Human-induced warming is amplified in the Arctic, but its causes and consequences are not precisely known. Here, we review scientific advances facilitated by the Polar Amplification Model Intercomparison Project. Surface heat flux changes and feedbacks triggered by sea-ice loss are critical to explain the magnitude and seasonality of Arctic amplification. Tropospheric responses to Arctic sea-ice loss that are robust across models and separable from internal variability have been revealed, including local warming and moistening, equatorward shifts of the jet stream and storm track in the North Atlantic, and fewer and milder cold extremes over North America. Whilst generally small compared to simulated internal variability, the response to Arctic sea-ice loss comprises a non-negligible contribution to projected climate change. For example, Arctic sea-ice loss is essential to explain projected North Atlantic jet trends and their uncertainty. Model diversity in the simulated responses has provided pathways to observationally constrain the real-world response.

Plastic pollution in the world's oceans threatens ecosystems and biodiversity. The connected nature of the marine environment suggests that coordinated actions by countries sharing an ocean border may provide more effective pollution control than unilateral actions by any one country. However, countries often fail to cooperate, even when joint economic benefits would be higher under cooperation. Here we present a modelling framework to determine the potential economic benefits of cooperative marine plastic pollution management. The framework integrates an estimated plastic transfer matrix from a particle tracking model with game theory to derive the economic benefits of international cooperation for 16 countries bordering the North Atlantic Ocean. Subject to modelling uncertainties, a fully cooperative agreement yields aggregate annual net benefits of around $36 billion and a 64% reduction in emissions. The net benefits of cooperation persist over alternative scenarios and considering the impact of uncertainties but vary in magnitude and distribution.

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.