Andrew R. Bell

Is an Epic Pluvial Masking the Water Insecurity of the Greater New York City Region

AbstractSix water emergencies have occurred since 1981 for the New York City (NYC) region despite the following: 1) its perhumid climate, 2) substantial conservation of water since 1979, and 3) meteorological data showing little severe or extreme drought since 1970. This study reconstructs 472 years of moisture availability for the NYC watershed to place these emergencies in long-term hydroclimatic context. Using nested reconstruction techniques, 32 tree-ring chronologies comprised of 12 species account for up to 66.2% of the average May–August Palmer drought severity index. Verification statistics indicate good statistical skill from 1531 to 2003. The use of multiple tree species, including rarely used species that can sometimes occur on mesic sites like Liriodendron tulipifera, Betula lenta, and Carya spp., seems to aid reconstruction skill. Importantly, the reconstruction captures pluvial events in the instrumental record nearly as well as drought events and is significantly correlated to precipitation...

Reimagining cost recovery in Pakistan's irrigation system through willingness‐to‐pay estimates for irrigation water from a discrete choice experiment

It is widely argued that farmers are unwilling to pay adequate fees for surface water irrigation to recover the costs associated with maintenance and improvement of delivery systems. In this paper, we use a discrete choice experiment to study farmer preferences for irrigation characteristics along two branch canals in Punjab Province in eastern Pakistan. We find that farmers are generally willing to pay well in excess of current surface water irrigation costs for increased surface water reliability and that the amount that farmers are willing to pay is an increasing function of their existing surface water supply as well as location along the main canal branch. This explicit translation of implicit willingness-to-pay (WTP) for water (via expenditure on groundwater pumping) to WTP for reliable surface water demonstrates the potential for greatly enhanced cost recovery in the Indus Basin Irrigation System via appropriate setting of water user fees, driven by the higher WTP of those currently receiving reliable supplies.

Detecting and interpreting secondary forest on an old Amazonian frontier

Land uses that replace tropical forests are important determinants of terrestrial carbon storage and biodiversity. This includes secondary forest growth after deforestation, which has been integrated into the REDD+ (Reducing Emissions from Deforestation and Forest Degradation) concept as a means to enhance current forest carbon stocks. Incorporating secondary forest into climate change mitigation efforts requires both accurate measurements and a means to target interventions to achieve additionality. We demonstrate how remote sensing and household survey data can be combined to meet these requirements in ‘old frontiers’ of the Brazilian Amazon and introduce the idea that annual land-cover transitions − measured at the pixel level and over time − can serve as leading indicators of secondary forest regrowth. The patterns we observe are consistent with the suggested tension between equity and additionality in REDD+: the poorest households on the poorest quality lots already allow forest regeneration. Policy interventions to encourage regeneration are likely to have the greatest additional impact on higher quality lots owned by better capitalized households.

Snow cover and precipitation impacts on dry season streamflow in the Lower Mekong Basin

[1]xa0Climate change impacts on dry season streamflow in the Mekong River are relatively understudied, despite the fact that water availability during this time is critically important for agricultural and ecological systems. Analyses of two gauging stations (Vientiane and Kratie) in the Lower Mekong Basin (LMB) show significant positive correlations between dry season (March through May, MAM) discharge and upper basin snow cover and local precipitation. Using snow cover, precipitation, and upstream discharge as predictors, we develop skillful regression models for MAM streamflow at Vientiane and Kratie, and force these models with output from a suite of general circulation model (GCM) experiments for the twentieth and twenty-first centuries. The GCM simulations predict divergent trends in snow cover (decreasing) and precipitation (increasing) over the twenty-first century, driving overall negligible long-term trends in dry season streamflow. Our study demonstrates how future changes in dry season streamflow in the LMB will depend on changes in snow cover and precipitation, factors that will need to be considered when assessing the full basin response to other climatic and non-climatic drivers.

Characterizing land-use change over space and time: applying principal components analysis in the Brazilian Legal Amazon

We apply a principal component analysis to characterize the dimensions of spatio-temporal change in agriculture within the Brazilian Legal Amazon for the period 1996–2006. Around 80% of spatio-temporal variation across a broad set of descriptors could be explained by four trajectories well observed in the region: large-scale ranching, inactive forested property, small-scale farming, and mechanized agriculture. Spatial clustering based on these trajectories reveals a shift in the characteristics of the agricultural frontier, and provides quantitative method for distinguishing functional sub-regions previously suggested in the literature. Our analysis suggests a marked growth in agriculture over the decade between 1996 and 2006, with agricultural development encroaching toward the interior of the Brazilian Amazon not only from the south and southeast, but also from the west.

Progress of constitutional change and irrigation management transfer in Pakistan: insights from a net-map exercise

Two current processes of institutional reform – irrigation management transfer (IMT) and the 18th Amendment to Pakistan’s Constitution – are expected to significantly impact agriculture and irrigation in Pakistan. Results are analyzed from a net-map exercise conducted with water-sector experts at the federal and provincial (Punjab) scales. The data suggest the potential for successful shifts of decision making under the 18th Amendment. However, weaker perceptions of the role of IMT in water governance were found than would be expected given its long history. This is further evidence that something new is necessary to help shift towards the decentralized IMT model.