Global change—Local values: Assessing tradeoffs for coastal ecosystem services in the face of sea level rise

Anthropogenic climate change poses a significant threat to Texas’ coastal habitats and in the Galveston Bay region, there is just under 1200 square miles of freshwater marsh and undeveloped dry upland. These habitats provide residents with a variety of key ecosystem services but are threatened by global climate change. Effective management of these resources requires multidisciplinary knowledge, combining an understanding of the potential biophysical habitat alterations associated with sea level rise with the measurement of residents’ value for coastal resources. In this study, we utilize a discrete choice experiment to investigate individuals’ preferences for future conditions of Texas habitats within the Galveston Bay region. Utilizing modeled output for coverage of freshwater marsh and undeveloped dry upland in the year 2050, respondents are asked to make trade-offs between coastal conditions with no further management actions and outcomes associated with specific management interventions. From this framework, we estimate Galveston Bay regional residents’ value for freshwater marshes and undeveloped uplands. Our results indicate that individuals are willing to conserve habitat under threat from sea level rise, but that they are likely unaware of the dynamic nature of that change. As a result, residents may place less emphasis on the role of the habitat migration in response to sea level rise.     

Land use changes and sea level rise may induce a “coastal squeeze” on the coasts of Veracruz,Mexico

“Coastal squeeze” refers to the process in which coastal ecosystems are threatened by the combination of sea level rise (SLR) and the presence of a physical barrier, such as human infrastructure. This situation prevents the landward migration of ecosystems and species, as the coastline moves inland, and they are thus exposed to local extinction. Our objective was to explore coastal squeeze in the state of Veracruz, Mexico, through the study of urban expansion on the coast, an analysis of coastline geodynamics, and a projection of the potential effect of SLR on the distribution of two focal plant species which are endemic to the coastal dunes of Mexico. Urbanization of the coast, parallel to the shoreline, has been taking place increasingly rapidly, displacing ecosystems, both natural (mangroves, beaches and coastal dunes) and transformed (cultivated fields and pastures). Taking into consideration the geodynamic trends of the coastline and an analysis of its historical evolution, it can be seen that the coastal strip is eroding at rates that vary from slow to very rapid. Finally, the results of ecological niche modeling indicate that, under scenarios of SLR, the potential distribution of the two focal species would diminish: Chamaecrista chamaecristoides by 6–28%, and Palafoxia lindenii by 2–15%. These results indicate that “coastal squeeze” is likely in the study area, and that measures to limit or mitigate this process are required. Such measures could include urbanization programs which limit development to appropriate zones, the restoration and rehabilitation of deteriorated ecosystems and the conservation of those ecosystems which are still healthy.     

Five years’ central pacific sea level from in situ array,satellite altimeter and numerical model: Research note

Abstract

Temporal and spatial features of central equatorial Pacific Ocean sea‐level variation appear similar, in measurements from two very different systems (one in the ocean and one carried on a satellite), and in results from a numerical model of the region. In particular, there is an interannual cycle: during El Nino, Kelvin waves appear at the equator, and the sea‐surface ridge associated with the equatorial current system shifts southward; in non‐El Nino years, instability waves appear at 6°N (strongest around the end of each calendar year), and the ridge shifts to the north. This three‐way comparison gives support to both measurement systems and to the numerical model.     

Variations in the atmospheric electric field and Meteorological parameters at a Tropical coastal urban station during 1936–40 and 1962–66

Summary The seasonal and diurnal variations in the vertical component of the atmospheric electric field, air temperature, relative humidity and horizontal wind speed were studied using the surface data for the two periods (1936–40) and (1962–66) recorded at the tropical urban station, Colaba, Bombay (18°51N, 72°49E, 11 m ASL), located on the west coast of India.The atmospheric electric field during the latter period (1962–66) is significantly higher (up to 42.3%) than the earlier period (1936–40). This has been attributed to the enhanced particulate concentrations in the atmosphere. The increase noticed in the atmospheric electric field is a maximum during winter and minimum during the monsoon. The atmospheric electric field exhibited a marked semi-diurnal oscillation with peaks at 0900 LST and 2200 LST during winter, premonsoon and post-monsoon seasons of both the periods. During the monsoon season the double oscillation is not marked.The variations noticed in the surface air temperature and the relative humidity are in agreement with those observed in the atmospheric electric field. The horizontal wind speed showed a decrease which has been attributed to the surface roughness resulting from urbanization.With 7 Figures     

Will coastal wetlands continue to sequester carbon in response to an increase in global sea level?: a case study of the rapidly subsiding Mississippi river deltaic plain

The highly visible coastal phenomenon of wetland loss in coastal Louisiana (LA) was examined through the prism of carbon accumulation and loss. Carbon storage or sequestration in rapidly subsiding LA coastal marsh soils was based on vertical marsh accretion and aerial change data. Marshes sequester significant amount of carbon through vertical accretion however, large amounts of carbon previously sequestration in the soil profile is lost through annual deterioration of these coastal marshes. Hurricanes, such as Katrina and Rita, have triggered instantaneous large carbon losses of sequestered soil carbon through the destruction of large areas of marsh. This analysis shows proposed coastal restoration efforts will not be sufficient to restore carbon losses by storms and marsh deterioration. Further, we have estimated the economic benefit of carbon sequestration for coastal wetland restoration efforts. Results show that LA coastal marshes may not serve as a net sink of carbon. These results may serve as a predictor of the impact of future predictions of increasing global sea level rise on carbon sequestration for other coastal regions.     

The ‘co’ in co-production of climate action: Challenging boundaries within and between science,policy and practice

Effective action taken against climate change must find ways to unite scientific and practice-based knowledges associated with the various stakeholders who see themselves as invested in the global delivery of climate governance. Political decision-makers, climate scientists and practitioners approach this challenge from what are often radically different perspectives and experiences. While considerable work has been done to develop the idea of ‘co-production’ in the development of climate action outputs, questions remain over how to best unite the contrasting epistemological traditions and norms associated with different stakeholders. Drawing on the existing literatures on climate action co-production and from translational perspectives on the science-policy interface, in this paper we develop the concept of ‘boundary agency’. Defining this as the agency ‘possessed’ when willing and able to translate between different epistemological communities invested in a similar policy and governance challenge such as climate change, we offer it as a useful means to reflect on participants’ understanding of the ‘co’ in co-production. This is in contrast to the more established (often academic-led) focus on what it is that is being produced by co-production processes. We draw from two complementary empirical studies, which explicitly encouraged i) engagement and ii) reflection on cross-boundary co-production between climate action stakeholders from different backgrounds. Reflecting on the two studies, we discuss the benefits of (and barriers to) encouraging more active and sustained engagement between climate action stakeholders so as to try to actively blur the boundaries between science and policy and, in doing so, invent new epistemological communities of practice.     

‘Splendid rains have fallen’: links between El Niño and rainfall variability in the Kalahari, 1840–1900

This study uses a range of published and unpublished historical documentary sources to explore the nature of rainfall variability in the Kalahari Desert and adjacent hardveld regions of central southern Africa during the seventeen Pacific El Niño–Southern Oscillation (ENSO) episodes that occurred between 1840 and 1900. Documentary data are used in two ways. First, maps of relative annual rainfall levels are presented for each of the 12 single-year and five protracted ENSO episodes during the period, in order to identify the associated inter-annual rainfall variations. These suggest that the relationship between ENSO episodes and rainfall variability identified for the twentieth century, whereby warm events are frequently preceded by wetter conditions during the austral summer prior to the event year and succeeded by drought in the following summer, has broadly held for much of the last 160 years. This is despite the long-term fluctuations in precipitation and temperature which are known to have occurred over this period. Droughts are identified following at least thirteen of the 17 single-year and protracted ENSO episodes. Pre-ENSO wetter periods are less common, with only nine of the ENSO episodes preceded by above-normal rainfall. Second, the documentary data are analyzed in detail in order to reveal any evidence for high resolution intra-annual variations in the seasonal distribution of rainfall during ENSO events. Seasonal sequences of rainfall/drought appear to have closely followed contemporary patterns, with heavy rainfall commonly occurring late in the pre-ENSO year or early in the ENSO year(s), and drought at the start of the post-ENSO year. This relationship can be seen to hold most strongly for single-year ENSO warm events and for the first year of protracted events, but rainfall conditions were more variable during the later years of protracted events.     

The stresses and dynamics of smallholder coffee systems in Jamaica’s Blue Mountains: a case for the potential role of climate services

Access to climate information has the potential to build adaptive capacity, improve agricultural profitability, and help manage risks. To achieve these benefits, knowledge of the local context is needed to inform information development, delivery, and use. We examine coffee farming in the Jamaican Blue Mountains (BM) to understand farmer livelihoods, opportunities for climate knowledge to benefit coffee production, and the factors that impinge on farmers’ ability to use climate information. Our analysis draws on interviews and 12 focus groups involving 143 participants who largely cultivate small plots. BM farmers currently experience stresses related to climate, coffee leaf rust, and production costs that interrelate concurrently and with time lags. Under conditions that reduce income, BM farmers compensate by adjusting their use of inputs, which can increase their susceptibility to future climate and disease stresses. However, farmers can also decrease impacts of future stressors by more efficiently and effectively allocating their limited resources. In this sense, managing climate, like the other stresses, is an ongoing process. While we identify climate products that can help farmers manage climate risk, the local context presents barriers that argue for interactive climate services that go beyond conventional approaches of information production and delivery. We discuss how dialogs between farmers, extension personnel, and climate scientists can create a foundation from which use can emerge.     

Scavenging Efficiency of ‘Aerosol Carbon’ and Sulfate in Supercooled Clouds at Mt. Sonnblick (3106 m a.s.l., Austria)

Cloud water and interstitial aerosol samples collected at Mt. Sonnblick (SBO) were analyzed for sulfate and aerosol carbon to calculate in-cloud scavenging efficiencies. Scavenging efficiencies for sulfate (_SO) ranged from 0.52 to 0.99 with an average of 0.80. Aerosol carbon was scavenged less efficiently with an average value (_AC) of 0.45 and minimum and maximum values of 0.14 and 0.81, respectively. Both _SO and _AC showed a marked, but slightly different, dependence on the liquid water content (LWC) of the cloud. At low LWC, _SO increased with rising LWC until it reached a relatively constant value of 0.83 above an LWC of 0.3 g/m³. In the case of aerosol carbon, we obtained a more gradual increase of _AC up to an LWC of 0.5 g/m³. At higher LWCs, _{_} remained relatively constant at 0.60. As the differences between _SO and _A varied across the LWC range observed at SBO, we assume that part of the aerosol carbon was incorporated into the cloud droplets independently from sulfate. This hypothesis is supported by size classified aerosol measurements. The differences in the size distributions of sulfate and total carbon point to a partially external mixture. Thus, the different chemical nature and the differences in the size and mixing state of the aerosol particles are the most likely candidates for the differences in the scavenging behavior.     

Reply to the comment by Addo Van Pul and John H. Van Boxel on ‘a first order closure scheme to describe counter gradient momentum transport in plant canopies’ by Li,Miller and Lin

Correspondence

Reply to the comment by Addo Van Pul and John H. Van Boxel on a first order closure scheme to describe counter gradient momentum transport in plant canopies by Li, Miller and Lin