Scary Outside
COVID-19, climate change, and the finite pool of worry in 2019 to 2021 Twitter discussions
Oleg Smirnov & Pei-Hsun Hsieh
Proceedings of the National Academy of Sciences, 25 October 2022
Abstract:
Climate change mitigation has been one of the world's most salient issues for the past three decades. However, global policy attention has been partially diverted to address the COVID-19 pandemic for the past 2 y. Here, we explore the impact of the pandemic on the frequency and content of climate change discussions on Twitter for the period of 2019 to 2021. Consistent with the “finite pool of worry” hypothesis both at the annual level and on a daily basis, a larger number of COVID-19 cases and deaths is associated with a smaller number of “climate change” tweets. Climate change discussion on Twitter decreased, despite 1) a larger Twitter daily active usage in 2020 and 2021, 2) greater coverage of climate change in the traditional media in 2021, 3) a larger number of North Atlantic Ocean hurricanes, and 4) a larger wildland fires area in the United States in 2020 and 2021. Further evidence supporting the finite pool of worry is the significant relationship between daily COVID-19 cases/deaths on the one hand and the public sentiment and emotional content of climate change tweets on the other. In particular, increasing COVID-19 numbers decrease negative sentiment in climate change tweets and the emotions related to worry and anxiety, such as fear and anger.
Extreme weather and climate policy
Sam Rowan
Environmental Politics, forthcoming
Abstract:
What effect does extreme weather have on climate policy? Existing studies show that weather shocks have negative economic impacts and increase public awareness of climate change. These findings help identify the impacts of climate change on economic and social systems, and provide reasons for governments to adopt climate policy reforms. However, questions remain about the overall link between local extreme weather shocks and government climate policy. I investigate the effect of temperature shocks and natural disasters on a range of national, international, and subnational climate policies in samples spanning 1990–2018. I find that neither temperature shocks nor natural disasters generate climate mitigation reforms. Given that climate policy is currently insufficient to manage climate change and climate impacts are expected to increase this century, these findings suggest that future climate shocks are unlikely to catalyze meaningful climate action.
A case for ensuring reductions in CO2 emissions are given priority over reductions in CH4 emissions in the near term
Paterson McKeough
Climatic Change, September 2022
Abstract:
For several base scenarios, the impacts, on the global mean temperature, of the time of instigation of reductions in emissions of carbon dioxide (CO2) and methane (CH4) were estimated using standard methods. It was confirmed that the necessary bending over of the global temperature curve is crucially dependent on the rapid phaseout of CO2 emissions. Reductions in CH4 emissions could be delayed till the period 2050–2080 without appreciably affecting the global temperature in 2100. For pathways consistent with the Paris Agreement, the analysis highlighted the dependence of the abatement costs associated with a temperature overshoot on whether the overshoot is primarily due to a delay in reducing CO2 emissions or primarily due to a delay in reducing CH4 emissions. A delay in reducing CO2 emissions increases both the overshoot and the abatement costs accrued over the century, whereas although it also increases the overshoot, a delay in reducing CH4 emissions until the period from 2050 to 2080 actually lowers overall abatement costs. To minimize the risk of the enabling resources being inadequate for the essential near-term reductions in CO2 emissions, a new instrument is needed to ensure that if the rate of reduction of CO2 emissions is deemed to be insufficient for achieving a 1.5 °C consistent pathway with limited overshoot, near-term reductions in CO2 emissions are given priority over near-term reductions in CH4 emissions. The replacement of the default GWP100 metric for CH4 by the time-dependent GTP metric, with the year 2100 as the endpoint, is proposed as the basis of the new instrument.
The Electric Ceiling: Limits and Costs of Full Electrification
David Rapson & James Bushnell
NBER Working Paper, October 2022
Abstract:
Electrification is a centerpiece of global decarbonization efforts. Yet there are reasons to be skeptical of the inevitability, or at least the optimal pace, of the transition. We discuss several under-appreciated costs of full, or even deep, electrification. Consumer preferences can operate in favor of and in opposition to electrification goals; and electrification is likely to encounter physical and economic obstacles when it reaches some as-yet-unknown level. While we readily acknowledge the external benefits of decarbonization, we also explore several under-appreciated external costs. The credibility and eventual success of decarbonization efforts is enhanced by foreseeing and ideally avoiding predictable but non-obvious costs of promising abatement pathways. Thus, even with all of its promise, the degree of electrification may ultimately reach a limit.
Comprehensive evidence implies a higher social cost of CO2
Kevin Rennert et al.
Nature, 27 October 2022, Pages 687–692
Abstract:
The social cost of carbon dioxide (SC-CO2) measures the monetized value of the damages to society caused by an incremental metric tonne of CO2 emissions and is a key metric informing climate policy. Used by governments and other decision-makers in benefit–cost analysis for over a decade, SC-CO2 estimates draw on climate science, economics, demography and other disciplines. However, a 2017 report by the US National Academies of Sciences, Engineering, and Medicine1 (NASEM) highlighted that current SC-CO2 estimates no longer reflect the latest research. The report provided a series of recommendations for improving the scientific basis, transparency and uncertainty characterization of SC-CO2 estimates. Here we show that improved probabilistic socioeconomic projections, climate models, damage functions, and discounting methods that collectively reflect theoretically consistent valuation of risk, substantially increase estimates of the SC-CO2. Our preferred mean SC-CO2 estimate is $185 per tonne of CO2 ($44–$413 per tCO2: 5%–95% range, 2020 US dollars) at a near-term risk-free discount rate of 2%, a value 3.6 times higher than the US government’s current value of $51 per tCO2. Our estimates incorporate updated scientific understanding throughout all components of SC-CO2 estimation in the new open-source Greenhouse Gas Impact Value Estimator (GIVE) model, in a manner fully responsive to the near-term NASEM recommendations. Our higher SC-CO2 values, compared with estimates currently used in policy evaluation, substantially increase the estimated benefits of greenhouse gas mitigation and thereby increase the expected net benefits of more stringent climate policies.
Lower test scores from wildfire smoke exposure
Jeff Wen & Marshall Burke
Nature Sustainability, forthcoming
Abstract:
Wildfires have increased in frequency and severity over the past two decades, threatening to undo substantial air quality improvements. We investigate the relationship between wildfire smoke exposure and learning outcomes across the United States using standardized test scores from 2009–2016 for nearly 11,700 school districts and satellite-derived estimates of daily smoke exposure. Relative to a school year with no smoke, average cumulative smoke-attributable PM2.5 (surface particulate matter <2.5 μg m−3) exposure during the school year (~35 μg m−3) reduces test scores by ~0.15% of a standard deviation. These impacts are more pronounced among younger students and are observed across differing levels of economic disadvantage and racial/ethnic composition. Additionally, we project that smoke PM2.5 exposure in 2016 reduced discounted future earnings by nearly $1.7 billion ($111 per student). Roughly 80% of these costs are borne by disadvantaged districts. Our findings quantify a previously unaccounted for social cost of wildfire that is likely to worsen under a warming climate.
Inefficient and unlit natural gas flares both emit large quantities of methane
Genevieve Plant et al.
Science, 30 September 2022, Pages 1566-1571
Abstract:
Flaring is widely used by the fossil fuel industry to dispose of natural gas. Industry and governments generally assume that flares remain lit and destroy methane, the predominant component of natural gas, with 98% efficiency. Neither assumption, however, is based on real-world observations. We calculate flare efficiency using airborne sampling across three basins responsible for >80% of US flaring and combine these observations with unlit flare prevalence surveys. We find that both unlit flares and inefficient combustion contribute comparably to ineffective methane destruction, with flares effectively destroying only 91.1% (90.2, 91.8; 95% confidence interval) of methane. This represents a fivefold increase in methane emissions above present assumptions and constitutes 4 to 10% of total US oil and gas methane emissions, highlighting a previously underappreciated methane source and mitigation opportunity.
Climate-related discussions in firms' 10-K: Who does it and what is its impact?
Sankarshan Basu et al.
Economics Letters, forthcoming
Abstract:
We examine the impact of climate-related discussions in the Management Discussion & Analysis (MD&A) section of the 10-K filings of S&P 500 firms from 2007 to 2018 and find that only firms from three specific industries (Energy, Utilities and Finance) have such discussions. We also find that the increase in mention of climate related words and ngrams is significantly associated with a fall in holding period return (HPR), post the filing date and especially post the Paris agreement. This suggests that investors perceive higher climate change discussion in a negative light even without any change in fundamentals.
The U.S. Manufacturing Sector’s Response to Higher Electricity Prices: Evidence from State-Level Renewable Portfolio Standards
Ann Wolverton, Ronald Shadbegian & Wayne Gray
NBER Working Paper, September 2022
Abstract:
While several papers examine the effects of renewable portfolio standards (RPS) on electricity prices, they mainly rely on state-level data and there has been little research on how RPS policies affect manufacturing activity via their effect on electricity prices. Using plant-level data for the entire U.S. manufacturing sector and all electric utilities from 1992 – 2015, we jointly estimate the effect of RPS adoption and stringency on plant-level electricity prices and production decisions. To ensure that our results are not sensitive to possible pre-existing differences across manufacturing plants in RPS and non-RPS states, we implement coarsened exact covariate matching. Our results suggest that electricity prices for plants in RPS states averaged about 2% higher than in non-RPS states, notably lower than prior estimates based on state-level data. In response to these higher electricity prices, we estimate that plant electricity usage declined by 1.2% for all plants and 1.8% for energy-intensive plants, broadly consistent with published estimates of the elasticity of electricity demand for industrial users. We find smaller declines in output, employment, and hours worked (relative to the decline in electricity use). Finally, several key RPS policy design features that vary substantially from state-to-state produce heterogeneous effects on plant-level electricity prices.
A Demonstration of a Simple Methodology of Flood Prediction for a Coastal City Under Threat of Sea Level Rise: The Case of Norfolk, VA, USA
Tal Ezer
Earth's Future, September 2022
Abstract:
Many coastal cities around the world are at risk of increased flooding due to sea level rise (SLR), so here a simple flood prediction method is demonstrated for one city at risk, Norfolk, VA, on the U.S. East Coast. The probability of future flooding is estimated by extending observed hourly water level for 1927–2021 into hourly estimates until 2100. Unlike most other flood prediction methods, the approach here does not use any predetermined probability distribution function of extreme events, and instead a random sampling of past data represents tides and storm surges. The probability of flooding for 3 different flood levels and 3 different SLR projections are calculated, and the results are consistent with more sophisticated methods. Under intermediate-low SLR projection an empirical formula is found to estimate the lower bound of flooding time, showing that water level that exceeds the high tide (Mean Higher High Water, MHHW) occurred ∼0.3% of the time in the 1960s, increased to ∼6% in 2021, and projected to occur 100% of the time by ∼2080. Under intermediate SLR projection, 1000 simulations of the probability of maximum annual water level were conducted, showing that storm surges may reach ∼2 m over MHHW by 2050 and ∼3 m over MHHW by 2100; in comparison, storm surges in Norfolk over the past 90 years reached 1.6 m only once. The method derived here could be adopted to other locations and help planning mitigations and adaptation strategies for cities at risk.
Invisible ship tracks show large cloud sensitivity to aerosol
Peter Manshausen et al.
Nature, 6 October 2022, Pages 101–106
Abstract:
Cloud reflectivity is sensitive to atmospheric aerosol concentrations because aerosols provide the condensation nuclei on which water condenses. Increased aerosol concentrations due to human activity affect droplet number concentration, liquid water and cloud fraction, but these changes are subject to large uncertainties. Ship tracks, long lines of polluted clouds that are visible in satellite images, are one of the main tools for quantifying aerosol–cloud interactions. However, only a small fraction of the clouds polluted by shipping show ship tracks. Here we show that even when no ship tracks are visible in satellite images, aerosol emissions change cloud properties substantially. We develop a new method to quantify the effect of shipping on all clouds, showing a cloud droplet number increase and a more positive liquid water response when there are no visible tracks. We directly detect shipping-induced cloud property changes in the trade cumulus regions of the Atlantic, which are known to display almost no visible tracks. Our results indicate that previous studies of ship tracks were suffering from selection biases by focusing only on visible tracks from satellite imagery. The strong liquid water path response we find translates to a larger aerosol cooling effect on the climate, potentially masking a higher climate sensitivity than observed temperature trends would otherwise suggest.