Showing posts with label Academic Study/Journal Article. Show all posts
Showing posts with label Academic Study/Journal Article. Show all posts

Wednesday, June 14, 2023

Life Cycle Air Pollution, Greenhouse Gas, and Traffic Externality Benefits and Costs of Electrifying Uber and Lyft

Abstract 
Transportation network companies (TNCs), such as Uber and Lyft, have pledged to fully electrify their ridesourcing vehicle fleets by 2030 in the United States. In this paper, Aniruddh Mohan, Matthew Bruchon, Jeremy Michalek, and Parth Vaishnav introduce AgentX, a novel agent-based model built in Julia for simulating ridesourcing services with high geospatial and temporal resolution.  The authors then instantiate this model to estimate the life cycle air pollution, greenhouse gas, and traffic externality benefits and costs of serving rides based on Chicago TNC trip data from 2019 to 2022 with fully electric vehicles. They estimate that electrification reduces life cycle greenhouse gas emissions by 40–45% (9–10¢ per trip) but increases life cycle externalities from criteria air pollutants by 6–11% (1–2¢ per trip) on average across our simulations, which represent demand patterns on weekdays and weekends across seasons during prepandemic, pandemic, and post-vaccination periods. A novel finding of their work, enabled by their high resolution simulation, is that electrification may increase deadheading for TNCs due to additional travel to and from charging stations. This extra vehicle travel increases estimated congestion, crash risk, and noise externalities by 2–3% (2–3¢ per trip). Overall, electrification reduces net external costs to society by 3–11% (5–24¢ per trip), depending on the assumed social cost of carbon.
by Aniruddh Mohan, Matthew Bruchon, Jeremy Michalek, and Parth Vaishnav 
Environmental Science & Technology https://pubs.acs.org/journal/esthag via ACS https://pubs.acs.org
Volume 57, Issue 23, pages 8524–8535; Publication Date: June 1, 2023

Tuesday, June 13, 2023

The regional economic impact of wildfires: Evidence from Southern Europe

Abstract
Sarah Meier, Robert J.R. Elliott and Eric Strobl estimate the impact of wildfires on the growth rate of gross domestic product (GDP) and employment of regional economies in Southern Europe from 2011 to 2018. To this end the authors match Eurostat economic data with geospatial burned area perimeters based on satellite imagery for 233 Nomenclature of Territorial Units for Statistics (NUTS) 3 level regions in Portugal, Spain, Italy, and Greece. Their panel fixed effects instrumental variable estimation results suggest an average contemporary decrease in a region’s annual GDP growth rate of 0.11–0.18% conditional on having experienced at least one wildfire. For an average wildfire season this leads to a yearly production loss of 13–21 billion euros for Southern Europe. The impact on the employment growth rate is heterogeneous across economic activity types in that there is a decrease in the average annual employment growth rate for activities related to retail and tourism (e.g., transport, accommodation, food service activities) of 0.09–0.15%, offset by employment growth in insurance, real estate, administrative, and support service related activities of 0.13–0.22%.
Journal of Environmental Economics and Management via Elsevier Science Direct www.ScienceDirect.com
Volume 119; May, 2023, Pages 102823

Friday, June 9, 2023

Tree cover and property values in the United States: A national meta-analysis

Abstract
[A meta-analysis by Kent Kovacs, Grant West, David J. Nowak and Robert G. Haight] uses 21 hedonic property value studies and 157 unique observations to study the influence of tree cover on the value of homes in the United States. The authors construct elasticity estimates of the percentage change in home value for a 1% change in the percentage of tree cover around a home. Cluster weighted averages of the elasticities account for the housing market and the precision of the property price effects for tree cover on and off property and for three categories of tree cover density. Meta-regression models further control for the housing market and tree cover heterogeneity, the methodological techniques of the primary study, and publication bias. The Mundlak meta-regression model with controls for US regions has the lowest out-of-sample transfer error. The larger elasticity for off property tree cover than on property tree cover (unless tree density is 10% or lower) suggests that the property value of homes rises more if tree cover is not on land that homeowners are responsible for maintaining. The elasticity in neighborhoods with greater than 25% tree cover (0.013) is four times larger than the elasticity in neighborhoods with 0 to 10% tree cover (0.003).
...
Their Mundlak model 2 predicts an $8.88 increase in the value of a single-family home in the Midwest for an on-property increase in tree cover of 0.18%.6 Assuming that the single-family home is on a half-acre lot (21,780 ft2) with an average tree cover of 18% (3920 ft2) (Table 2), they find that a 1% increase in the percentage tree cover amounts to an increase of 39 ft2. Suppose that a 24-in. dbh green ash tree has a crown radius of 35 ft. and a crown area of 962 ft2. A 1% increase in tree cover is equivalent to 0.04 additional 24-in. green ash trees on the property (39/962 = 0.04). The increase in property value for one green ash tree on the property is $8.88/0.04 = $222. Their Mundlak model 2 also predicts a $76.2 increase in the value of a single-family home in the Midwest for a 0.18% increase in tree cover within a mile of the home. A circular area with 1-mile radius has 87.6 million ft2. Using the average tree cover of 18% (Table 2), they find that trees cover 15.8 million ft2, and a 1% increase in the percentage tree cover amounts to an increase of 158,000 ft2. Suppose again a 24-in. dbh green ash tree has a crown radius of 35 ft. and a crown area of 962 ft2. A 1% increase in tree cover is equivalent to 164 additional 24-in. dbh green ash trees within a mile of the home (158,000/962 = 164).
https://www.nature.org/en-us/what-we-do/our-priorities/build-healthy-cities/cities-stories/benefits-of-trees-forests/
What is the total value of a 1% increase in tree cover in a neighborhood? Here, [they] need to calculate the increase in value of all the homes in the neighborhood, and so [they] need an estimate of housing density. According to the 2019 US Census, there are 2,176 households per square mile in St. Paul, MN. If we assume the neighborhood is a circular mile in size, then there are 2176 * 3.14 = 6833 homes in the neighborhood (there are 3.14 mile2 in a circular mile). If each home benefits from the 1% increase in tree cover in the circular area, then the aggregate increase in property value is 6833 * $76.2 = $520,675, for the off-property component of the tree cover. In addition, the aggregate increase in property value is 164 * $222 = $36,408 for the on-property component of tree cover, again assuming the 1% increase in tree cover is composed of 164 24-in. dbh ash trees. Adding those two components, the total value of a 1% increase in tree cover in the circular mile area is $557,083 or $277 per acre of land.

by Kent Kovacs, Grant West, David J. Nowak and Robert G. Haight
Ecological Economics via Elsevier Science Direct www.Sciencedirect.com
Volume 197, July 2022, 107424

Tuesday, May 23, 2023

New damage curves and multimodel analysis suggest lower optimal temperature

Abstract:
Economic analyses of global climate change have been criticized for their poor representation of climate change damages. Here we develop and apply aggregate damage functions in three economic Integrated Assessment Models (IAMs) with different degrees of complexity. The damage functions encompass a wide but still incomplete set of climate change impacts based on physical impact models. [The authors] show that with medium estimates for damage functions, global damages are in the range of 10% to 12% of GDP by 2100 in a baseline scenario with 3 °C temperature change, and about 2% in a well-below 2 °C scenario. These damages are much higher than previous estimates in benefit-cost studies, resulting in optimal temperatures below 2 °C with central estimates of damages and discount rates. Moreover, [they] find a benefit-cost ratio of 1.5 to 3.9, even without considering damages that could not be accounted for, such as biodiversity losses, health and tipping points.
Fig. 1: Overview of the creation and use of the damage functions.

Fig. 2: End-of-century damages for the five macro-regions for two scenarios.


by Kaj-Ivar van der Wijst, Francesco Bosello, Shouro Dasgupta, Laurent Drouet, Johannes Emmerling, Andries Hof, Marian Leimbach, Ramiro Parrado, Franziska Piontek, Gabriele Standardi & Detlef van Vuuren 
Nature Climate Change https://www.nature.com Volume 13, Pages 434–441 (2023)

Monday, May 22, 2023

An Analysis of U.S. Multi-Family Housing, Eco-Certifications, & Walkability

Abstract:
This paper examines the persistence of differentiated pricing in the multi-family housing related to eco-certification. In examining a sample of market rents for non-specialty, multi-family properties both across the U.S., as well as those areas that enjoy the highest concentrations of LEED certified apartments, Jeremy Gabe, Karen McGrath, Spenser Robinson and Andrew Sanderford find rental premiums of 10.2% and 14.7%, respectively for those properties with LEED certification. The addition of the continuous Walk Score, to control for variations in urban form, results in premiums of 7.4% and 9.6%, respectively. These findings are directionally consistent with those found in earlier studies, and demonstrate a persistence in rental premiums for certified properties over time, and with increased LEED adoption.
https://tinyurl.com/2o4r3tp2

by Jeremy Gabe,Karen McGrath,Spenser Robinson &Andrew Sanderford
Article: 2162515; Published online: 17 Jan 2023

Sunday, May 21, 2023

Who Benefits from Hazardous Waste Cleanups? Evidence from the Housing Market

Abstract
The Resource Conservation and Recovery Act (RCRA) manages cleanup of hazardous waste releases at over 3,500 sites across the US, which covers approximately 17.5% of all developed land in the country. This paper evaluates the national housing market impacts of cleanups performed under RCRA and estimates the program's impacts on neighborhood change. We find that cleanups near residential properties yield significant, yet localized, increases in home prices, and that impacts are concentrated in the lower deciles of the price distribution. Importantly, we find no evidence of sorting along socio-demographic dimensions in response to cleanup. Our findings suggest that cleanup benefits accrue to the residents who are the original “hosts” of pollution and could correct pre-existing disparities in exposure to land-based contamination.
...
This paper evaluates the housing market impacts of cleanups conducted under the Resource Conservation and Recovery Act (RCRA). We find that the positive environmental impacts from RCRA cleanups are reflected in the housing market, indicating that people are aware of cleanups and value the water quality improvements documented in Cassidy et al. (2020). The price increases that we find are driven by cleanups concentrated among the lowest price deciles of the census tract in which the RCRA facility is located: Prices increase by 11% for the 1st decile of the price distribution, and we detect no evidence of a price increase for the 9th decile. This indicates cleanups raise housing values of the poorest segments of the population, which are likely to face other disadvantageous circumstances in life and are typically more vulnerable to the deleterious effects of pollution (see, e.g. Apelberg, Buckley and White, 2005). 

Furthermore, we find that the benefits of cleanups accrued to those living closest to the sites and, notably, do not find that cleanups induced re-sorting. This is consistent with the localized price impacts that we find, but somewhat surprising given how expansive RCRA cleanups were and the recent literature that has highlighted the potential for policies to worsen underlying inequities (Hausman and Stolper, 2020; Bakkensen and Ma, 2020). Ultimately, whether environmental cleanups lead to neighborhood turnover is an empirical question that has far-reaching consequences for whether a policy would exacerbate pre-existing socio-economic disparities.

The Valley of the Drums, a toxic waste dump in northern Bullitt County, Kentucky
https://en.wikipedia.org/wiki/Hazardous_waste#/media/File:Valleyofdrums.jpg

by Alecia W. Cassidy, Elaine L. Hill & Lala Ma
National Bureau of Economic Research (NBER) www.NBER.org
Working Paper 30661; Issue Date November 2022

Policies, Projections, and the Social Cost of Carbon: Results from the DICE-2023 Model

Abstract
The present study examines the assumptions, modeling structure, and preliminary results of DICE-2023, the revised Dynamic Integrated Model of Climate and the Economy (DICE), updated to 2023. The revision contains major changes in the carbon and climate modules, the treatment of non-industrial greenhouse gases, discount rates, as well as updates on all the major components. The major changes are a significantly lower level of temperature of the cost-benefit optimal policy, a lower cost of reaching the 2° C target, an analysis of the impact of the Paris Accord, and a major increase in the estimated social cost of carbon.
...
Table 7 and Figure 7 show estimates of the social cost of carbon (SCC). The SCC in the baseline run is $61/tCO2 for the 2020 period (in 2019 international $). This is above the SCC for the C/B (Cost/Benefit) optimal run of $53/tCO2 because damages are smaller in the C/B optimum. It is far below the SCC for the 2 °C run of $85/tCO2. The higher SCC in the temperature-limited run reflects the economic interpretation that a tight temperature limit is equivalent to a damage function with a sharp kink at the temperature limit and therefore to a sharply higher damage function above 2 °C. Note that the estimates of the SCC in the current DICE version are significantly above those in earlier vintages for reasons discussed in other sections, see particularly the next section. 

One of the most instructive findings involves the importance of discounting for the SCC and other policies. Table 7 shows the powerful impact of discounting on the SCC. The social cost of carbon at a 5% discount rate is two-thirds of the DICE C/B optimal estimate for 2020, while that of a 1% discount rate is 8 times the DICE C/B optimal estimate for 2020.
Additionally, Figure 8 compares estimates of the SCC with several other current values. The GIVE model is a comprehensive estimate prepared by researchers at Resources for the Future using probabilistic estimates of output and other components of damage estimates (Rennert et al., 2022). It uses a relatively low discount rate and has a relatively high social cost of carbon. A second set of estimates pertains to the SCC used by the federal government and prepared by an interagency working group. Figure 8 shows draft SCC estimates from EPA (2022) for both their overall assessment and specific to a damage module based on the DSCIM model (Climate Impacts Lab, 2022) for near-term discount rates from 1.5% to 2.5%. Conditional on discounting assumptions, the EPA estimates align very closely with those of DICE-2023. Figure 8 also shows a draft update (OMB, 2021) based on earlier methods and models which did not contain recommended methodological updates. This estimate is notably lower than the corresponding value in DICE-2023. The key takeaway from Figure 8 is the importance of the discount rate in determining the SCC.

A major change in the results of the DICE model over the years has been the rising estimates of the social cost of carbon. The original DICE-1992 model did not calculate a SCC, which came later to climate-change economics. However, rerunning the baseline scenario for the 1992 model gives an estimate of $18/tCO2 compared to $61/tCO2 in the 2023 model (in 2019$). The upward revision is a notable illustration of the evolving scientific understanding of damages, discount rates, and levels of output. Further research will provide a decomposition of the sources of the change in SCC due to different components.

by Lint Barrage & William D. Nordhaus
National Bureau of Economic Research (NBER) www.NBER.org
Working Paper 31112; Issue Date: April, 2023

Friday, May 12, 2023

Air pollution and health impacts of oil & gas production in the United States

Abstract
Oil and gas production is one of the largest emitters of methane, a potent greenhouse gas and a significant contributor of air pollution emissions. While research on methane emissions from oil and gas production has grown rapidly, there is comparatively limited information on the distribution of impacts of this sector on air quality and associated health impacts. Understanding the contribution of air quality and health impacts of oil and gas can be useful for designing mitigation strategies. Here we assess air quality and human health impacts associated with ozone, fine particulate matter, and nitrogen dioxide from the oil and gas sector in the US in 2016, and compare this impact with that of the associated methane emissions. We find that air pollution in 2016 from the oil and gas sector in the US resulted in 410 000 asthma exacerbations, 2200 new cases of childhood asthma and 7500 excess deaths, with $77 billion in total health impacts. NO2 was the highest contributor to health impacts (37%) followed by ozone (35%), and then PM2.5 (28%). When monetized, these air quality health impacts of oil and gas production exceeded estimated climate impact costs from methane leakage by a factor of 3. These impacts add to the total life cycle impacts of oil and gas, and represent potential additional health benefits of strategies that reduce consumption of oil and gas. Policies to reduce oil and gas production emissions will lead to additional and significant health benefits from co-pollutant reductions that are not currently quantified or monetized. 
by Jonathan J Buonocore5,1, Srinivas Reka2, Dongmei Yang2, Charles Chang2, Ananya Roy3, Tammy Thompson3, David Lyon3, Renee McVay3, Drew Michanowicz4 and Saravanan Arunachalam2
1 Boston University School of Public Health, Boston, MA, United States of America jjbuono@bu.edu
2 Institute for the Environment, University of North Carolina, Chapel Hill, NC, United States of America
3 Environmental Defense Fund, Washington, DC, United States of America
4 Physicians, Scientists, and Engineers for Healthy Energy, Oakland, CA, United States of America
Environmental Research: Health https://iopscience.iop.org/journal/2752-5309 via IPO Science https://iopscience.iop.org/
Volume 1, Number 2; Published 8 May 2023 

Thursday, May 11, 2023

Health, air pollution, and location choice

Abstract:
This paper provides evidence that air-pollution-related health conditions change how households evaluate clean air and, as a result, incentivize them to relocate to locations with better air quality. The evidence implies that naive estimations of the adverse effect of air pollution on health are biased, as people sort on air quality differently depending on their health. [The author employs] a spatial-equilibrium model in which households choose a county to live in based on county-level characteristics including air pollution. Using National Longitudinal Survey of Youth data, [the author creates] a panel tracking respondents’ respiratory health shocks and county-level location for over three decades. The estimates from a multinomial mixed logit model support the hypothesis that households move to cleaner-air locations after an adult is diagnosed with asthma. [Siyu Pan finds] that households react more strongly to an asthma diagnosis for an adult than to a child’s diagnosis. The estimated median increase in marginal willingness to pay for a one-unit reduction in Air Quality Index after a diagnosis of adult-onset asthma is $157–$830 (in constant 1982–84 dollars).
Air Quality by County

by Siyu Pan, Department of Economics, Georgia State University, 55 Park Place, Atlanta, GA 30302, United States of America and The W. A. Franke College of Business, Northern Arizona University, 
Journal of Environmental Economics and Management https://www.sciencedirect.com/journal/journal-of-environmental-economics-and-management via Elsevier Science Direct www.ScienceDirect.com
Volume 119; May, 2023; 102794, Available online 22 February 2023

Wednesday, May 10, 2023

The Value of Scattered Greenery in Urban Areas: A Hedonic Analysis in Japan

Abstract
This study investigates the impact of scattered greenery (street trees and yard bushes), rather than cohesive greenery (parks and forests), on housing prices. The authors identify urban green space from high-resolution satellite images and combine these data with data on both condominium sales and rentals to estimate hedonic pricing models. They find that scattered urban greenery within 100 meters significantly increases housing prices, while more distant scattered greenery does not. Scattered greenery is highly valued near highways, and the prices of inexpensive and small for-sale and for-rent properties are less affected by scattered greenery. These results indicate that there is significant heterogeneity in urban greenery preferences by property characteristics and location. This heterogeneity in preferences for greenery could lead to environmental gentrification since the number of more expensive properties increases in areas with more green amenities.
...
Their results show that a 10% increase in scattered greenery within 100 m increases the price of apartments for sale by approximately 2 to 2.5% (from 740,000 to 930,000 JPY) when evaluated at average housing prices. 

Sander et al. (2010), who analyzed green space in Minnesota, reported that a 10% increase in the tree canopy within 100 m increased the average housing price by 0.48% and that the average tree canopy within 250 m increased the average price by 0.29%. Their estimated impact, which is larger than those in previous works, could be caused by the characteristics of the study area. Their study area has little green space, so the value of greenery could be high (Brander and Koetse 2011; Siriwardena et al. 2016). Additionally, trees and grasses that reduce noise and pollution might be highly valued due to the high population density and traffic in their study area (Perino et al. 2014; Votsis 2017). The authos provide a subsample analysis in the following sections and address the mechanisms underlying the results of these green assessments.

by Yuta Kuroda & Takeru Sugasawa
Environmental and Resource Economics  via Springerlink www.SpringerLink.com
Volume 85, Pages523–586 (2023)

Saturday, January 22, 2022

Valuing the Impact of Air Pollution in Urban Residence Using Hedonic Pricing and Geospatial Analysis, Evidence From Quito, Ecuador

Abstract
This study attempts to determine the marginal willingness to pay for cleaner air in the Metropolitan District of Quito (DMQ) Equador by estimating the impact of air pollutants on property values. Spatial interpolation techniques portray pollutant concentrations in the DMQ.  A hedonic model estimates air pollution impacts on properties.  Impacts of three pollutants, (Particulate Matter-PM2.5, Nitrogen Dioxide-NO2, and Sulfur Dioxide-SO2) were estimated. The impact were statistically significant with decreases in property values of between 1.1% and 2.8%, or between $1,846.20 and $4,984.74 US$.
...
The most significant impact was from NO2 with a coefficient of ‒2.765, meaning that an increase in 1% of this pollutant will have a 2.8% decrease in the property price.  NOx is one of the very few air pollutants that people are able to perceive. This result is significant since the average residence value is 865.13 US$/m2, meaning a reduction in house value of 23.92 US$/m2. The other one is O3, which was also statistically significant, but only at 10%. The impact of a 1% increase in concentration of O3 will decrease the residence value 7.41 US$/m2. The other two air pollutants are odorless. PM2.5, had a coefficient of ‒1.733 and was statistically significant at the 95%  level. implying that an increase of 1% in PM2,5 concentrations will reduce a property's value 14.99 US$/m2. CO had a coefficient of ‒1,103 and was significant at 99%, meaning that an increase in CO concentration will reduce home value by 9.54 US$/m2
https://doi.org/10.1177/11786221211053277
by Sebastian Borja-Urbano, Fabián Rodríguez-Espinosa, Marco Luna-Ludeña
Universidad de las Fuerzas Armadas – ESPE, Sangolquí, Ecuador
Corresponding Author: Fabián Rodríguez-Espinosa, Departamento de Ciencias de la Tierra y Construcción, Universidad de las Fuerzas Armadas ESPE, Av. Gral. Rumiñahui s/n, Sangolquí, Ecuador. Email: ffrodriguez3@espe.edu.ec
Air, Soil and Water Research via Sage Publications
Volume 14; First Published November 22, 2021; Open Access

Wednesday, January 19, 2022

Comparing Pollution Where You Live and Play: A Hedonic Analysis of Enterococcus in the Long Island Sound

Abstract:
Hedonic property value studies of water quality conventionally focus on water quality levels measured nearest a home. This study examines whether water quality at the nearest access point (i.e., a beach) matters more to local residents.  Megan Kung, Dennis Guignet and Patrick Walsh conduct a hedonic analysis of water quality in the Long Island Sound, where an aging infrastructure and heavy precipitation lead to frequent sewage overflows. The analysis focuses on bacteria contamination and beach closures at various access points and monitoring sites. Results suggest that decreases in water quality measured at the nearest beach yield a larger negative effect and impact homes at a farther spatial extent than previously suggested in the literature.
...
Model 1 has two variants (SAC and FE) which follow the conventional approach in the literature and link homes to the water quality measures at the closest monitoring site.  The SAC is a general spatial model, which includes a spatiotemporal lag of neighboring house prices as a means to account for spatially correlated omitted variables and FE is a municipality-by-year fixed-effects model.  The SAC 1 results suggest homes within 500 meters (m.) of the Sound are affected the most, experiencing an average decrease in price of 0.16% for a 10% increase in enterococci. For the homes in this distance bin, which have an average price of $1,001,651, this translates to an average decrease in home value of $1,583. A similar elasticity is estimated for the 500–1,000 m bin. Any negative elasticity estimates beyond 1,000 m are statistically insignificant. The estimated price effects are small relative to the overall price of a home, but are in line with previous estimates.  The corresponding FE 1 model suggests a negative, but small and statistically insignificant, elasticity in the nearest-distance bin. The –0.0127 elasticity in the 500–1,000 m bin is similar to that of the SAC 1 model, but the two models differ in that the FE 1 model suggests possible negative elasticities as far as 2,000 m.
Cladophora, a wiry green seaweed, is found in great abundance in Little Narragansett Bay, fertilized by a high load of nitrogen entering the bay. Dense mats of the seaweed are oxygen factories during the day, but use up all of the oxygen during the night, leaving none for the animals. Only animals tolerant of very low oxygen, ones who can essentially hold their breath through the night, are found in areas where this seaweed is thick. In mid-summer, the seaweed is so abundant and productive, excess oxygen bubbles out of the water and can cause large mats of the seaweed to float to the surface. Credit: Jamie Vaudrey, UConn https://phys.org/news/2017-02-unveils-tool-cleaner-island.html

In SAC and FE Models 2 and 3, the authors deviate from the conventional approach of matching to the nearest monitoring site, and instead explicitly account for water quality at the nearest beach. In doing so, they see that any previously negative coefficients corresponding to water quality at the portion of the waterbody nearest the home are now statistically insignificant.

In Model 2 when they consider water quality at the closest beach (conditional on water quality measured nearest the home), there is a strong negative effect that is larger in magnitude and spatial extent. SAC 2 shows that among homes nearest a beach (0–500 m bin), a 10% increase in enterococci decreases house prices by 0.31%. These homes have an average price of $1,259,349, and so this translates to an average implicit price of $3,904. This result is virtually identical in the FE variant of Model 2.  Results suggest that the negative elasticity associated with water quality at the nearest beach could extend to 3,500 m. For homes in the farthest significant distance bin in SAC 2 (3,000–3,500 m, which have an average price of $844,851), the mean implicit price for a 10% increase in enterococci levels at the nearest beach is a decrease of $1,369.  The FE 2 model suggests that this effect is even larger; the estimated –0.0531 elasticity for the 3,000–3,500 m bin suggests an average implicit price of $4,486. The statistically significant effects of beach enterococci levels are not consistently found in all distance bins out to 3,500 m.
...
In a meta-analysis of hedonic property value studies examining water quality, Guignet et al. (2020) report a mean elasticity with respect to fecal coliform counts of –0.018 and –0.020 for waterfront and non-waterfront homes within 500 m, respectively. These are quite similar to our estimated elasticities with respect to enterococci counts.
...
In the SAC 3 and FE 3 models, they account for the number of beach closure days in summer. The results suggest that home buyers and sellers do, on average, respond more to beach closures than to enterococci levels. The estimated price effects of beach closures are of the expected negative sign, with robust and statistically significant negative effects in all distance bins out to 2,000 m from the beach. With the exception of the 2,000–2,500 m bin, we find significant negative effects extending out to 3,500 and even 4,500min models SAC 3 and FE 3, respectively. In general, the estimated beach closures effect in the SAC and FE models are very similar. These more robust, farther extending, and statistically significant estimates seem reasonable given that beach closures and notifications are a more direct and salient signal to local residents regarding water quality. When comparing estimates across the variants of Models 2 and 3 in table 3, we see that accounting explicitly for beach closures decreases the magnitude and/or significance of the estimated beach enterococci elasticities, especially in the nearest-distance bins.
...
For one additional beach day closed each summer season, the estimates translate to an average decrease in home value of $2,123 for homes in the 0–500 m bin, and $598 for homes in the 3,000–3,500 m bin. These estimates suggest that if the nearest beach is closed an additional week every year, there would be an average price decrease of $14,859 for homes in the 0–500 m bin, and $4,188 for homes in the 3,000–3,500 m bin. This is a plausible magnitud  given that the average number of beach days closed per season is seven, and there have been instances where beaches were closed for most of, or even the entire, season.
...
With these caveats in mind, local stakeholders can still make better-informed decisions by comparing the potential house price effects estimated in this study with the costs of policies and projects to improve water quality in the Long Island Sound.... Consider a hypothetical program in New Rochelle, a city in Westchester County, that reduces the number of beach closures each summer season from the average of seven days a year to zero. Our results from SAC 3, for example, suggest that this would yield a total increase in value of the 5,672 single-family homes and townhomes within 3.5 km of a beach in New Rochelle by about $50.2 million. Note that we omitted homes in the statistically insignificant 2,000–2,500m. bin for this calculation. As a rough comparison, a project to repair the sewer infrastructure and prevent stormwater infiltration and subsequent sewage overflows in New Rochelle cost about $20 million (Garcia 2015b), which is substantially less than the estimated capitalization effects in this purely illustrative example. These capitalization effects reflect only a portion of the benefits to local stakeholders because households farther away who use these beaches will also benefit.

https://www.journals.uchicago.edu/doi/suppl/10.1086/717265
by Megan Kung 1, Dennis Guignet 2, and Patrick Walsh 3
1. Economist, Los Angeles Regional Water Quality Control Board, 320 W. 4th Street #200, Los Angeles, CA 90013 USA (email: megan.kung@waterboards.ca.gov). 
2. Assistant Professor, Department of Economics, Appalachian State University, 416 Howard Street, Room 3101B, Peacock Hall, ASU Box 32051, Boone, NC 28608 USA (email: guignetdb@appstate.edu).
3. Economist, National Center for Environmental Economics, US Environmental Protection Agency, 1200 Pennsylvania Avenue, NW, Washington, DC 20460 USA (email: walsh.patrick.j@epa.gov).
Published online December 3, 2021.
Marine Resource Economics via The University of Chicago Press on behalf of the MRE Foundation Volume 37, Number 1, January 2022.

Friday, January 8, 2021

Local Sectoral Specialization in a Warming World

Abstract:
This paper quantitatively assesses the world's changing economic geography and sectoral specialization due to global warming. It proposes a two-sector dynamic spatial growth model that incorporates the relation between economic activity, carbon emissions, and temperature. The model is taken to the data at the 1° by 1° resolution for the entire world. Over a 200-year horizon, rising temperatures consistent with emissions under Representative Concentration Pathway 8.5 push people and economic activity northwards to Siberia, Canada, and Scandinavia. Compared to a world without climate change, clusters of agricultural specialization shift from Central Africa, Brazil, and India's Ganges Valley, to Central Asia, parts of China and northern Canada. Equatorial latitudes that lose agriculture specialize more in non-agriculture but, due to their persistently low productivity, lose population. By the year 2200, predicted losses in real GDP and utility are 6% and 15%, respectively. Higher trade costs make adaptation through changes in sectoral specialization more costly, leading to less geographic concentration in agriculture and larger climate-induced migration.
...



The Value of Time in the United States: Estimates from Nationwide Natural Field Experiments

Abstract
The value of time determines relative prices of goods and services, investments, productivity, economic growth, and measurements of income inequality. Economists in the 1960s began to focus on the value of non-work time, pioneering a deep literature exploring the optimal allocation and value of time. By leveraging key features of these classic time allocation theories, we use a novel approach to estimate the value of time (VOT) via two large-scale natural field experiments with the ridesharing company Lyft. We use random variation in both wait times and prices to estimate a consumer's VOT with a data set of more than 14 million observations across consumers in U.S. cities. We find that the VOT is roughly $19 per hour (or 75% (100%) of the after-tax mean (median) wage rate) and varies predictably with choice circumstances correlated with the opportunity cost of wait time. Our VOT estimate is larger than what is currently used by the U.S. Government, suggesting that society is under-valuing time improvements and subsequently under-investing public resources in time-saving infrastructure projects and technologies

https://en.wikipedia.org/wiki/History_of_timekeeping_devices


Conclusion
Having gotten this far in our study you have surely invested a fair amount of time. We hope that such time was indeed an investment, and not ill-spent. This is because time is the ultimate scarce resource, and its value has deep implications for a range of economic phenomena and investment decisions. Our starting point is a literature from the 1960s that had deep implications for our understanding of the family, the household, and time allocation more generally. We leverage insights from these classic time allocation theories to provide a theoretically-consistent but updated approach to estimate the VOT. The theory carefully directs two large-scale natural field experiments on the Lyft platform to estimate the causal effects of wait time and price on ride-share demand.

We report several interesting insights. First, we estimate a VOT that is roughly $19 per hour (2015 prices). This estimate is 75-80% of the mean wage rate for the various regions in our experiment, which is quantitatively different from the findings of previous empirical studies on the VOT (Small et al., 2007) and is greater than the existing US policy guidelines on the VOT (USDOT, 2015). Second, we document that, consistent with standard microeconomic models (Becker, 1965; DeSerpa, 1971), the VOT is related to the opportunity cost of time, the available substitute set, and other key features of the trip that impact marginal benefits and marginal costs. Third, taken in aggregate, our research has key implications for policy. Specifically, we recommend that policymakers: (i) account for the great deal of VOT heterogeneity with respect to cities, locations within cities, day of week, and time of day; and (ii) adjust the rule-of-thumb VOT estimates up to 75% of the after-tax mean wage rate otherwise.

Sources of Cost Overrun in Nuclear Power Plant Construction Call for a New Approach to Engineering Design

Highlights
• US nuclear plant cost estimation does not align with observed experience
• “Indirect” expenses, largely soft costs, contributed a majority of the cost rise
• Safety-related factors were important but not the only driver of cost increases
• Mechanistic models inform innovation by relating engineering design to cost change

Summary
Nuclear plant costs in the US have repeatedly exceeded projections. Here, we use data covering 5 decades and bottom-up cost modeling to identify the mechanisms behind this divergence. We observe that nth-of-a-kind plants have been more, not less, expensive than first-of-a-kind plants. “Soft” factors external to standardized reactor hardware, such as labor supervision, contributed over half of the cost rise from 1976 to 1987. Relatedly, containment building costs more than doubled from 1976 to 2017, due only in part to safety regulations. Labor productivity in recent plants is up to 13 times lower than industry expectations. Our results point to a gap between expected and realized costs stemming from low resilience to time- and site-dependent construction conditions. Prospective models suggest reducing commodity usage and automating construction to increase resilience. More generally, rethinking engineering design to relate design variables to cost change mechanisms could help deliver real-world cost reductions for technologies with demanding construction requirements.
...
The history of nuclear energy in the US is one of mixed results. Rapid capacity growth in the 1960s was accompanied by significant unit upscaling, followed by operational improvements and rising capacity factors. But in the 1970s, rising project durations and costs, alongside studies on thermal pollution and low-level radiation, became a source of public controversy. Following the 1979 Three Mile Island accident, a long hiatus of nuclear construction began. Rising construction costs and project delays have continued to affect efforts to expand nuclear capacity in the US since the 1970s. A survey of plants begun after 1970 shows an average overnight cost overrun of 241%. Since the 1990s, two nuclear projects have begun construction, both two-reactor expansions of existing generating stations. The VC Summer project in South Carolina was abandoned in 2017 with sunk costs of $9B, and the Vogtle project in Georgia is severely delayed. Current estimates place the total price of the Vogtle expansion at $25B ($11,000/kW), almost twice as high as the initial estimate of $14B, and costs are anticipated to rise further.

Challenges in nuclear construction are not unique to the US. Recent projects in Finland (Olkiluoto 3) and France (Flamanville 3) have also experienced cost escalation, cost overrun, and schedule delays. Cost estimates for a plant under construction in the United Kingdom (Hinkley Point C) have been revised upward. In contrast to the experience in Western Europe and the US, however, China, Japan, and South Korea have achieved construction durations shorter than the global median since 1990. Cost and construction duration tend to correlate (e.g., Lovering et al.), but it should be noted that cost data from these countries are largely missing or are not independently verified. (Cost data should be provided and audited by entities not actively involved in plant procurement and construction, including data from international organizations or government agencies as opposed to data from utilities and reactor equipment providers.)
[The researchers concluded that between 1976 and 1987, indirect costs—those external to hardware—caused 72% of the cost increase. “Most aren’t hardware-related but rather are what we call soft costs,” says Trancik. “Examples include rising expenditures on engineering services, on-site job supervision, and temporary construction facilities.”]












Percentage contribution of variables to increases in containment building costs These panels summarize types of variables that caused costs to increase between 1976 and 2017. In the first time period (left panel), the major contributor was a drop in the rate at which materials were deployed during construction. In the second period (middle panel), the containment building was redesigned for improved safety during possible emergencies, and the required increase in wall thickness pushed up costs. Overall, from 1976 to 2017 (right panel), the cost of a containment building more than doubled.

As the left and center panels above show, the importance of those mechanisms changed over time. Between 1976 and 1987, the cost increase was caused primarily by declining deployment rates; in other words, productivity dropped. Between 1987 and 2017, the containment building was redesigned for passive cooling, reducing the need for operator intervention during emergencies. The new design required that the steel shell be approximately five times thicker in 2017 than it had been in 1987—a change that caused 80% of the cost increase over the 1976–2017 period.

Thursday, January 7, 2021

Climate Finance

Abstract:
We review the literature studying interactions between climate change and financial markets. We first discuss various approaches to incorporating climate risk in macro-finance models. We then review the empirical literature that explores the pricing of climate risks across a large number of asset classes including real estate, equities, and fixed income securities. In this context, we also discuss how investors can use these assets to construct portfolios that hedge against climate risk. We conclude by proposing several promising directions for future research in climate finance.
...
Our review of the current literature is organized into two parts. In the first section, we discuss efforts to incorporate climate risk into macro-finance models. The pioneering work of Nordhaus (1977) paved the way for thinking about the interaction of the physical process of climate change with the real economy. Early papers in this literature — such as Nordhaus (1977, 1991, 1992) — focused on optimal climate change mitigation, and worked in deterministic settings. As such, these papers did not directly speak to the ways in which climate change affects asset prices and risk premia. Subsequent work extends these models to incorporate different aspects of risk and uncertainty about climate change and its link to the economy. These attributes include the stochastic nature of physical and economic processes as well as uncertainty about models of these processes (see, for example, the work by Kolstad, 1992, Manne et al., 1992, Nordhaus, 1994, Kelly & Kolstad, 1999, Nordhaus & Popp, 1997, Weitzman, 2001, 2009, Lemoine & Traeger, 2012, Golosov et al., 2014). Much of this literature has focused on the way risks and uncertainties affect optimal mitigation policies and the “social cost of carbon.” More recently, the financial economics literature has explored the implications of these models for the prices and returns of financial assets.

In the second part of this review article, we discuss the empirical literature that explores the pricing of climate risk across a large number of asset classes. This literature considers the price effects of at least two broad categories of climate related risk factors: physical climate risk and transition risk. Physical climate risk includes risks of the direct impairment of productive assets resulting from climate change; transition risk includes risks to cash flows arising from a possible transition to a lowcarbon economy. A central element of the research designs in these papers is that assets are differentially exposed to these climate risk factors: for example, houses located near the sea are more exposed to physical climate risks, while coal companies are more exposed to transition risks. Many papers then combine the differential exposure of assets within an asset class with time-varying attention paid to climate risk in order to understand how this type of risk is priced in asset markets. We review research that documents climate-related asset price effects in equity markets, bond markets, housing markets, and mortgage markets. We also discuss recent work that shows how one can use financial assets to construct portfolios that hedge climate change risks.
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To sum up, the debate around the term structure of discount rates for valuing investments to mitigate climate change (and its effects on the social cost of carbon) can in large part be traced to different assumptions about the nature of the shocks that mitigation investments are hedging, and about the dynamics of the economy and the climate in response to those shocks. While this two-dimensional distinction does not fully span the variety of models that have been written in the literature, it helps to understand what has lead the literature to reach different (sometimes opposite) conclusions.
https://www.climatepolicyinitiative.org/publication/global-landscape-of-climate-finance-2019/
...
Lemoine (2020) argues that accounting for model uncertainty leads to higher estimates of the social cost of carbon than would otherwise prevail. ... Uncertainty thus introduces a new channel that impacts asset prices in the form of covariance between model parameters and agents’ consumption. This induces precautionary savings and risk premia effects in addition to those resulting from stochastic shocks in standard unambiguous models. Viewing damage uncertainty as a compound lottery, when the
agent “draws” an especially adverse damage parameter, carbon mitigation becomes especially valuable and raises the social cost of carbon (as long as relative risk aversion is greater than one, as commonly assumed in calibrations of macro and finance models).
...
Barnett et al. (2020) analyze the additional incremental effects of ambiguity aversion on the social cost of carbon. Holding fixed the extent of model uncertainty, they compare model calibrations with ambiguity averse investors versus a model with ambiguity neutrality.  Ambiguity aversion magnifies the cost of carbon by roughly 60% to 70% in current value terms relative to the baseline scenario with model uncertainty but ambiguity neutrality.
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Krueger et al. (2020) conduct a survey of active investment managers to explore their approaches to managing climate risk. They find that investors believe that climate change has significant financial implications for portfolio firms, and that considerations of climate risk are important in the investment process. For example, 39% of investors in the survey reported to be working to reduce the carbon footprints in their portfolios. These survey responses are also consistent with findings from Alok et al. (2020), who show that fund managers adjust their portfolios in response to climatic disasters. Pedersen et al. (forthcoming) provide an ESG CAPM framework and outline how investor beliefs and preferences regarding climate change risks (and ESG considerations more broadly) fit in with the factor model paradigm that dominates empirical asset pricing research.
...
Given the attention that investors dedicate to climate change, a growing literature explores the pricing of various dimensions of climate risk in equity markets (e.g., Hong et al., 2019). Much of this literature has focused on the effects of regulatory climate risk, where different measures of carbon intensity or environmental friendliness are often used as proxies for regulatory climate risk. For example, Bolton & Kacperczyk (2020) analyze U.S. equity markets, and demonstrate that firms with higher carbon emissions are valued at a discount. Quantitatively, the authors estimate that a one standard deviation increase in emissions across firms is associated with a rise in expected returns of roughly 2% per annum. The authors trace this effect at least in part to exclusionary screening performed by institutional investors to limit the carbon risk in their portfolios. In related work, Hsu et al. (2020) show a similar spread in average returns between high- and low-pollution firms, and link it to uncertainty about environmental policy. Engle et al. (2020) document that stocks of firms with high E-Scores — which the authors argue capture lower exposure to regulatory climate risk — have higher returns during periods with negative news about the future path of climate change. Similarly, Choi et al. (2020) explore global stock market data and find that stocks of carbon-intensive firms underperform during times with abnormally warm weather, a period when investors’ attention to climate risks are likely to be particularly high. Barnett (2020) uses an event study analysis to explore financial market impacts of regulatory risk. He finds that increases in the likelihood of future climate policy action lead to decreased equity prices for firms with high exposure to climate policy risk. Similar evidence of the pricing of climate risk can be found in equity options markets. Ilhan et al. (2019) show that the cost of option protection against extreme downside risks is larger for firms with more carbon-intense business models, and particularly so at times when there is an increased public attention to climate risk.

















..
Climate risks may also affect financial assets beyond equities. Municipal bond markets are a particularly interesting setting for analyzing the financial market implications of climate risk. In particular, when considering the physical risks of climate change, firms may be at risk depending on the location of their production facilities. However, even the most exposed firms usually have the option of relocating their modes of production to other geographies. Municipalities have no such luxury. As a result, one would expect that municipal debt backed by tax revenues from localities more exposed to physical climate risks such as rising sea levels or wildfires would trade at a substantial discount. In evidence along these lines, Painter (2020) shows that at-issuance municipal bond yields are higher for counties with large expected losses due to sea level rise (SLR). Consistent with the hypothesis that such price differences reflect the pricing of climate risk, he finds that this effect is concentrated in long-dated bonds and essentially absent at short maturities over which the likelihood of SLR remains low. In related work, Goldsmith-Pinkham et al. (2019) show via a structural model that this effect of SLR on municipal bond yields is tantamount to a 3–8% reduction in the present value of local government long-run cash flows.
...
To implement this dynamic hedging strategy, it is necessary to determine which firms increase or decrease in value when there is news around climate change.  Engle et al. (2020) solve this problem by proxying for firms’ climate risk exposures using “E-Scores” that capture various aspects of how environmentally friendly a firm is. The hedge portfolio would then overweight high-E-Score firms, and underweight lowE-Score firms, with the relative weights updated dynamically as more data on the relationship between E-Scores, climate news, and asset prices is obtained. While it is straightforward to construct such a hedge with the benefit of hindsight, the true test of a hedge portfolio is its ability to profit in adverse conditions on an out-of-sample basis. Indeed, Engle et al. (2020) find an out-of-sample correlation of 20% to 30% between the return of the hedge portfolio and innovations in the WSJ climate change news index. In summary, the paper provides a rigorous methodology for constructing portfolios to hedge against climate risks that are otherwise difficult to insure.
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Zillow economist Krishna Rao (2017) calculates that a six feet sea level rise would put 1.9 million homes worth about $882 billion at risk of flooding, with about half the losses coming from Florida alone. 
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Using these data, Giglio et al. (2020) show that while properties in a flood zone generally trade at a premium compared to otherwise similar properties (likely because of positive amenities such as beach access), this premium compresses in periods with elevated attention paid to climate risk. Quantitatively, a doubling in the Climate Attention Index (i.e., a doubling in the share of listings that mention climate risk-related words) is associated with a relative 2.4% decline in the transaction prices of properties in the flood zone.
...
A number of other papers exploit related research designs to explore the pricing of climate risk in real estate markets. Bernstein et al. (2019) also explore the relationship between house prices and sea level rise (SLR). They find that houses that are exposed to sea level rise sell for a discount compared with observably equivalent unexposed properties. The authors are able to control for the distance from the beach, which allows them to alleviate some concerns around differential amenity values of these properties. Quantitatively, properties that will be inundated after one foot of global average SLR sell at a 14.7% discount, properties inundated with two to three feet of SLR sell at a 13.8% discount, and properties inundated with six feet of SLR sell at a discount of 4.4%. Baldauf et al. (2020) present related evidence suggesting that the extent to which physical climate risk is priced in housing markets depends on whether the local population believes in climate change. Bakkensen & Barrage (2017) explore a similar point, highlighting that when individuals who do not believe in climate change disproportionately sort to purchase more exposed properties, this will reduce the extent to which climate change risk is priced in housing markets.

Tuesday, January 5, 2021

Carbon Pricing and Innovation in a World of Political Constraints

Executive Summary:
Workshop Purpose
- In March 2020, a workshop of academic and policy experts was convened including economists, political scientists, energy innovation scholars and policy practitioners, seeking to synthesize collective expertise and academic research and to reflect on the role of carbon pricing and innovation in climate policy.
- Participants discussed the experience with carbon pricing around the world and the way forward for carbon pricing as a climate policy tool, including political feasibility, economic efficiency, and interaction and integration with other policy mechanisms. The workshop emphasized in particular the importance of political economy considerations on the design, implementation, and durability of climate policies.

Main Points of Discussion
- Carbon pricing has been an important pillar of climate policy discussions, facing no shortage of support from economists and policymakers favoring cost-effective reductions in carbon pollution. To date, around 15% of global carbon emissions are subject to carbon prices, most well under $50/tCO₂.
- Real-world experience with carbon pricing policies is mixed. In Sweden and British Columbia, carbon taxes have led to some emissions reductions, while many other places have low and ineffectual prices. Jurisdictions like Australia and Ontario, Canada have also rolled back policies. Broad-scale experience in California, the Northeast and mid-Atlantic (RGGI) states, and the EU has shown that carbon pricing systems should be seen in the context of wider climate policies and can be a source of revenues for other policy objectives.
- Key criteria for climate policy design are environmental efficacy, cost-effectiveness, and political feasibility as well as durability over time and the interaction of carbon pricing with broader climate, environmental, economic and social policies and political priorities.
- Political challenges in the form of wavering public support and interest group pressures can handicap carbon price policies as prices rise and benefits are perceived as diffuse. Research indicates this is particularly true in nations with higher income inequality.
- Carbon prices supported by complementary innovation and industrial policies can bring down technology and compliance costs and can potentially be sequenced to build political coalitions for more expansive climate policy over time.

Key Recommendations
- Well implemented carbon pricing policies are a potentially important tool in the climate policy toolkit. However, carbon pricing cannot stand alone. Politically feasible carbon pricing policies are not sufficient to drive emissions reductions or innovation at the scale and pace necessary.
- Carbon pricing should be implemented as part of a comprehensive suite of climate policies, such as clean energy standards, low or no-carbon transportation projects, government procurement and subsidy for market adoption of emerging technologies, and direct support for clean energy research, development, demonstration, and deployment (RDD&D).
- Using revenues from carbon pricing for clean energy RDD&D, public infrastructure projects, public procurement or subsidy, and alleviating distributional burdens associated with climate policy, may further decarbonization goals and increase public support.
...
Mechanisms
Carbon pricing can be most directly implemented through a carbon tax or cap-and-trade system. Tax instruments provide greater price certainty; quantity instruments, like cap-and-trade, provide greater emissions certainty. Under a carbon tax, the carbon price remains stable, while emissions can vary depending upon the degree to which emitters choose to pay the tax versus reducing emissions. Carbon prices are often designed to increase over time—a feature that may increase their efficacy while undermining their popularity. With cap-and-trade programs, the emissions level is set by the cap, while the price can vary depending upon the supply and demand for allowances. In practice, quantity and price instruments can be hybridized to achieve some of the benefits of both approaches. California’s cap-and-trade system, for example, includes price floors and ceilings to limit price uncertainties.

Other cap-and-trade design considerations concern carbon “leakage”—the potential for carbon pricing in one jurisdiction or sector to lead to increases in emissions in other jurisdictions or sectors—and other trade implications, emissions hotspots, linkage to other systems, and whether or not to allow carbon offsets. All these decisions need to weigh a number of competing environmental, economic, and political priorities.

The Social Cost of Carbon
One metric often combined—and all-too-often confused—with conversations around carbon pricing is the social cost of carbon (SCC). The SCC, technically the “SC-CO2,” is typically defined as the marginal social damage, or cost, of one additional ton of carbon dioxide (CO2) being emitted into the atmosphere. It plays an important role in shaping policy decisions across the world, providing a metric to measure the economic harm of climate impacts, and to thereby calculate the benefit of regulatory or policy action. To calculate the SCC, researchers estimate the current and future CO2 or broader GHG emissions impacts on the economy, earth systems, and human welfare. Computing the SCC combines modeling of complex economic, behavioral, and geophysical systems.

Social cost of carbon calculations have a long and storied history. Yale economist Bill Nordhaus was one early pioneer. He shared the Nobel Prize in economics for his efforts leading to the calculation of the SCC. His calibrations have been famously conservative, leading to an SCC of around $40/ton of CO2 (tCO2) emitted today, a number similar to that calculated by the Obama Administration’s Interagency Working Group for the Social Cost of Carbon. Recent work applying the same fundamental benefit-cost model has led to SCC estimates of at least $100/tCO2, sometimes $200/tCO2 and above, typically driven by updated climate damage and discount rate assumptions. Most unknowns and unknowables result in still higher SCC estimates. The same goes for other extensions such as more disaggregated climate damage functions, and heterogeneity within and across countries, which result in estimates of around $400/tCO2.

Tuesday, December 1, 2020

Site Conditions, Maintenance Costs, and Plant Performance of 10 Extensive Green Roofs in the Research Triangle Area of Central North Carolina

Summary
Compared with traditional roofing, green roofs (GRs) have quantifiable environmental and economic benefits, yet limited research exists on GR plant survival, maintenance practices, and costs related to plant performance. The objective of this study was to assess plant cover, site conditions, and maintenance practices on 10 extensive GRs in the Research Triangle Area of North Carolina. Green roof maintenance professionals were surveyed to assess plant performance, maintenance practices, and maintenance costs. Vegetation cover on each site was characterized.

Relationships among plant performance and environmental and physical site characteristics, and maintenance practices were evaluated. Survey respondents ranked weed control as the most problematic maintenance task, followed by irrigation, pruning, and debris removal. No single design or maintenance factor was highly correlated with increased plant cover. Green roof age, substrate organic matter, and modular planting methods were not correlated with greater plant cover.
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Results showed a trend that irrigation increased plant cover. Plants persisting on GRs included several species of stonecrop (Sedum sp.), but flame flower (Talium calycinum) and ice plant (Delosperma basuticum) were also present in high populations on at least one roof each. Green roof maintenance costs ranged from $0.13/ft2 to $3.45/ft2 per year, and were greater on sites with more weeds and frequent hand watering.

Thursday, November 12, 2020

Monetising the savings of remotely sensed data and information in Burn Area Emergency Response (BAER) wildfire assessment

Abstract
We used a value of information approach to demonstrate the cost-effectiveness of using satellite imagery as part of the Burn Area Emergency Response (BAER), a US federal program that identifies imminent post-wildfire threats to human life and safety, property and critical natural or cultural resources. We compared the costs associated with producing a Burn Area Reflectance Classification map and implementing a BAER when imagery from satellites (either Landsat or a commercial satellite) was available to when the response team relied on information collected solely by aerial reconnaissance. The case study included two evaluations with and without Burn Area Reflectance Classification products: (a) savings of up to US$51 000 for the Elk Complex wildfire incident request and (b) savings of a multi-incident map production program. Landsat is the most cost-effective way to input burn severity information into the BAER program, with savings of up to US$35 million over a 5-year period.
by Richard Bernknopf, Yusuke Kuwayama, Reily Gibson, Jessica Blakely, Bethany Mabee, T.J. Clifford, Brad Quayle, Justin Epting, Terry Hardy, and David Goodrich
International Journal of Wildland Fire - https://www.publish.csiro.au/wf
Published online: 22 October 2020