Reducing emissions from deforestation and forest degradation (REDD+) has gained international attention over the past decade, as manifested in both United Nations policy discussions and hundreds of ...voluntary projects launched to earn carbon-offset credits. There are ongoing discussions about whether and how projects should be integrated into national climate change mitigation efforts under the Paris Agreement. One consideration is whether these projects have generated additional impacts over and above national policies and other measures. To help inform these discussions, we compare the crediting baselines established ex-ante by voluntary REDD+ projects in the Brazilian Amazon to counterfactuals constructed ex-post based on the quasi-experimental synthetic control method. We find that the crediting baselines assume consistently higher deforestation than counterfactual forest loss in synthetic control sites. This gap is partially due to decreased deforestation in the Brazilian Amazon during the early implementation phase of the REDD+ projects considered here. This suggests that forest carbon finance must strike a balance between controlling conservation investment risk and ensuring the environmental integrity of carbon emission offsets. Relatedly, our results point to the need to better align project- and national-level carbon accounting.
Magnetic reconnection is of fundamental importance to plasmas because of its role in releasing and repartitioning stored magnetic energy. Previous results suggest that this energy is predominantly ...released as ion enthalpy flux along the reconnection outflow. Using Magnetospheric Multiscale data we find the existence of very significant electron energy flux densities in the vicinity of the magnetopause electron dissipation region, orthogonal to the ion energy outflow. These may significantly impact models of electron transport, wave generation, and particle acceleration.
Atmospheric aerosols are complex mixtures of different chemical species, and individual particles exist in many different shapes and morphologies. Together, these characteristics contribute to the ...aerosol mixing state. This review provides an overview of measurement techniques to probe aerosol mixing state, discusses how aerosol mixing state is represented in atmospheric models at different scales, and synthesizes our knowledge of aerosol mixing state's impact on climate‐relevant properties, such as cloud condensation and ice nucleating particle concentrations, and aerosol optical properties. We present these findings within a framework that defines aerosol mixing state along with appropriate mixing state metrics to quantify it. Future research directions are identified, with a focus on the need for integrating mixing state measurements and modeling.
Key Points
We define aerosol mixing state and connect it to the physicochemical properties of aerosol particles
We discuss existing measurements and models to understand chemical and physicochemical mixing state
We explain the connection between aerosol mixing state and climate‐relevant aerosol properties
Cassini Observes the Active South Pole of Enceladus Porco, C. C; Helfenstein, P; Thomas, P. C ...
Science (American Association for the Advancement of Science),
03/2006, Letnik:
311, Številka:
5766
Journal Article
Recenzirano
Odprti dostop
Cassini has identified a geologically active province at the south pole of Saturn's moon Enceladus. In images acquired by the Imaging Science Subsystem (ISS), this region is circumscribed by a chain ...of folded ridges and troughs at approximately55°S latitude. The terrain southward of this boundary is distinguished by its albedo and color contrasts, elevated temperatures, extreme geologic youth, and narrow tectonic rifts that exhibit coarse-grained ice and coincide with the hottest temperatures measured in the region. Jets of fine icy particles that supply Saturn's E ring emanate from this province, carried aloft by water vapor probably venting from subsurface reservoirs of liquid water. The shape of Enceladus suggests a possible intense heating epoch in the past by capture into a 1:4 secondary spin/orbit resonance.
•PPCDAm promoted a drastic conservation reform in Brazil.•Many PPCDAm-related activities are not discussed in the literature.•Recent surge in deforestation may jeopardize previous success from ...PPCDAm.
The Action Plan for the Prevention and Control of Deforestation in the Legal Amazon (PPCDAm), launched in 2004, promoted a drastic conservation reform in Brazil. To date, the plan has been through four distinct phases: PPCDAm-I (2004–2008), II (2009–2011), III (2012–2015), and IV (2016–2020). A substantial decline from historically high deforestation rates in the Amazon occurred from 2004 to 2012, part of which (particularly after 2007) can be attributed to the PPCDAm, and part to economic factors such as commodity prices and the currency exchange rates that affect the profitability of agricultural exports. After 2012 deforestation has trended upward despite control efforts. The PPCDAm evolved through its four phases, consequently changing the patterns of deforestation in Amazonia. Here, we review the conservation instruments and strategies promoted under the PPCDAm umbrella and, when possible, provide estimates of their impacts on deforestation based on rigorous, counterfactual evaluations. While the literature emphasizes some of the most well-known PPCDAm actions, e.g., improved satellite-based monitoring, the “blacklist” of municipalities, expansion of protected areas, land tenure regularization, credit access restrictions, and moratoria, we highlight a number of other PPCDAm activities that, along with the previous examples, are arguably also responsible for a significant share of the reduction of deforestation in the region.
Abstract
We present seven new transiting hot Jupiters from the WASP-South survey. The planets are all typical hot Jupiters orbiting stars from F4 to K0 with magnitudes of V = 10.3-12.5. The orbital ...periods are all in the range of 3.9-4.6 d, the planetary masses range from 0.4 to 2.3 M
Jup and the radii from 1.1 to 1.4 R
Jup. In line with known hot Jupiters, the planetary densities range from Jupiter-like to inflated (ρ = 0.13-1.07ρJup). We use the increasing numbers of known hot Jupiters to investigate the distribution of their orbital periods and the 3-4 d 'pile-up'.
ABSTRACT
We report the results of optical follow-up observations of 29 gravitational-wave (GW) triggers during the first half of the LIGO–Virgo Collaboration (LVC) O3 run with the Gravitational-wave ...Optical Transient Observer (GOTO) in its prototype 4-telescope configuration (GOTO-4). While no viable electromagnetic (EM) counterpart candidate was identified, we estimate our 3D (volumetric) coverage using test light curves of on- and off-axis gamma-ray bursts and kilonovae. In cases where the source region was observable immediately, GOTO-4 was able to respond to a GW alert in less than a minute. The average time of first observation was 8.79 h after receiving an alert (9.90 h after trigger). A mean of 732.3 square degrees were tiled per event, representing on average 45.3 per cent of the LVC probability map, or 70.3 per cent of the observable probability. This coverage will further improve as the facility scales up alongside the localization performance of the evolving GW detector network. Even in its 4-telescope prototype configuration, GOTO is capable of detecting AT2017gfo-like kilonovae beyond 200 Mpc in favourable observing conditions. We cannot currently place meaningful EM limits on the population of distant ($\hat{D}_L = 1.3$ Gpc) binary black hole mergers because our test models are too faint to recover at this distance. However, as GOTO is upgraded towards its full 32-telescope, 2 node (La Palma & Australia) configuration, it is expected to be sufficiently sensitive to cover the predicted O4 binary neutron star merger volume, and will be able to respond to both northern and southern triggers.
This study adapts the Faustmann model (1849) to include the effects of carbon-based payments for environmental services on the optimal rotation length of forest plantations. We assume payments occur ...at the end of the harvesting cycle and are based on the additional average carbon stock over the rotation length relative to an optimal management scenario without carbon incentives. We present numerical applications of our model based on the four most planted tree species in the world: Eucalyptus sp., Acacia sp., Pinus sp. and Tectona sp. Simulations were performed to quantify the impact of different payment levels (USD Mg CO2−1) on optimal rotation lengths and carbon stocks. We find diminishing sequestration returns to increasing carbon payments. Overall, our results suggest that targeting plantations with longer rotations, associated with slow-growing species, is a more cost-effective strategy to retain additional forest carbon stored (USD Mg CO2−1). However, such a strategy results in lower proportional increases in carbon stocks (Mg CO2 ha−1) compared to faster-growing species, which benefit the most from the carbon incentives. As a result, increasing payments for additional carbon stored could change the choice of which tree species to produce and ironically promote plantations with lower total carbon stocks.
•PES are based on the additional average carbon stock over the rotation length.•We find diminishing sequestration returns to increasing carbon payments.•Carbon payments may change the choice of which tree species to produce.
Microbial products are sensed through Toll-like receptors (TLRs) and trigger a program of dendritic cell (DC) maturation that enables DCs to activate T cells. Although an accepted hallmark of this ...response is eventual down-regulation of DC endocytic capacity, we show that TLR ligands first acutely stimulate antigen macropinocytosis, leading to enhanced presentation on class I and class II major histocompatibility complex molecules. Simultaneously, actin-rich podosomes disappear, which suggests a coordinated redeployment of actin to fuel endocytosis. These reciprocal changes are transient and require p38 and extracellular signal-regulated kinase activation. Thus, the DC actin cytoskeleton can be rapidly mobilized in response to innate immune stimuli to enhance antigen capture and presentation.
Indigenous territories in Brazil have existed since the pre-European discovery of the continent. Yet, many of them remain without formal recognition by the state. While numerous studies discuss the ...social implications of indigenous land (IL) designation, limited empirical evidence exists regarding its role in forest conservation. To address this gap, the present study employs a quasi-experimental design and causal-inference methods to estimate the effects of formal IL designation on deforestation across Brazil and its biomes, from 1986 to 2021. Estimates indicate an average impact of −0.05% on deforestation due to the formal designation of ILs nationwide, with variations ranging from −0.21% to 0.04% across different evaluation periods and biomes. Notably, designated ILs in the Cerrado biome had the highest avoided deforestation impacts (−0.12%, on average). No evidence of deforestation leakage was observed. The findings from this study suggest that while the promotion of formal IL designation can lead to consistent reductions in deforestation, the magnitude of its effect is relatively small to be promoted on the sole basis of an effective strategy to mitigate tropical deforestation and climate change. Nevertheless, the potential positive socioeconomic impacts of formal IL designation on indigenous peoples cannot be undermined.
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