Death in the Air
Valuing the Global Mortality Consequences of Climate Change Accounting for Adaptation Costs and Benefits
Tamma Carleton et al.
NBER Working Paper, July 2020
Abstract:
This paper develops the first globally comprehensive and empirically grounded estimates of mortality risk due to future temperature increases caused by climate change. Using 40 countries' subnational data, we estimate age-specific mortality-temperature relationships that enable both extrapolation to countries without data and projection into future years while accounting for adaptation. We uncover a U-shaped relationship where extreme cold and hot temperatures increase mortality rates, especially for the elderly, that is flattened by both higher incomes and adaptation to local climate (e.g., robust heating systems in cold climates and cooling systems in hot climates). Further, we develop a revealed preference approach to recover unobserved adaptation costs. We combine these components with 33 high-resolution climate simulations that together capture scientific uncertainty about the degree of future temperature change. Under a high emissions scenario, we estimate the mean increase in mortality risk is valued at roughly 3.2% of global GDP in 2100, with today's cold locations benefiting and damages being especially large in today's poor and/or hot locations. Finally, we estimate that the release of an additional ton of CO2 today will cause mean [interquartile range] damages of $36.6 [-$7.8, $73.0] under a high emissions scenario and $17.1 [-$24.7, $53.6] under a moderate scenario, using a 2% discount rate that is justified by US Treasury rates over the last two decades. Globally, these empirically grounded estimates substantially exceed the previous literature's estimates that lacked similar empirical grounding, suggesting that revision of the estimated economic damage from climate change is warranted.
Wildfire Exposure Increases Pro-Environment Voting within Democratic but Not Republican Areas
Chad Hazlett & Matto Mildenberger
American Political Science Review, forthcoming
Abstract:
One political barrier to climate reforms is the temporal mismatch between short-term policy costs and long-term policy benefits. Will public support for climate reforms increase as climate-related disasters make the short-term costs of inaction more salient? Leveraging variation in the timing of Californian wildfires, we evaluate how exposure to a climate-related hazard influences political behavior rather than self-reported attitudes or behavioral intentions. We show that wildfires increased support for costly, climate-related ballot measures by 5 to 6 percentage points for those living within 5 kilometers of a recent wildfire, decaying to near zero beyond a distance of 15 kilometers. This effect is concentrated in Democratic-voting areas, and it is nearly zero in Republican-dominated areas. We conclude that experienced climate threats can enhance willingness-to-act but largely in places where voters are known to believe in climate change.
Health co-benefits of achieving sustainable net-zero greenhouse gas emissions in California
Tianyang Wang et al.
Nature Sustainability, August 2020, Pages 597–605
Abstract:
The achievement of net-zero greenhouse gas (GHG) emissions by 2100 is required to limit global temperature rise below 2 °C above preindustrial levels. Earlier accomplishments of net-zero GHG emissions in developed regions support this global target. Here, we develop a road map for California to achieve net-zero GHG emissions sustainably in 2050 by using detailed modelling of energy system transformation, cross-sectoral connectivity and technology penetration, as well as quantify the associated health co-benefits from reduced co-emitted air pollutants. We find that approximately 14,000 premature deaths can be avoided in California in 2050 and that these health co-benefits are disproportionately higher in disadvantaged communities (that is, 35% of avoided deaths will come from 25% of the state’s population). The annualized monetary benefits (US$215 billion) exceed the GHG abatement cost (US$106 billion) by US$109 billion. This road map requires the use of bioenergy with carbon capture and sequestration technology to offset some GHG emissions. However, this technology comes at a price as it would emit a considerable amount of air pollutants and reduce health co-benefits by US$4 billion. Nevertheless, our analysis shows that ambitious GHG reduction efforts can provide substantial health co-benefits, especially for residents of disadvantaged communities.
How Hurricanes Sweep Up Housing Markets: Evidence from Florida
Joshua Graff Zivin, Yanjun Liao & Yann Panassie
NBER Working Paper, July 2020
Abstract:
This paper examines the impacts of hurricanes on the housing market and the associated implications for local population turnover. We first characterize the post-hurricane equilibrium dynamics in local housing markets using microdata from Florida during 2000-2016. Our results show that hurricanes cause an increase in equilibrium prices and a concurrent decrease in transactions in affected areas, both lasting up to three years. Together, these dynamics imply a negative transitory shock to the housing supply as a consequence of the hurricane. Furthermore, we match buyer characteristics from mortgage applications to provide the first buyer-level evidence on population turnover. We find that incoming homeowners in this period have higher incomes, leading to an overall shift in the local economic profile toward higher-income groups. Our findings suggest that market responses to destructive natural disasters can lead to uneven and lasting demographic changes in affected communities, even with a full recovery in physical capital.
In climate news, statements from large businesses and opponents of climate action receive heightened visibility
Rachel Wetts
Proceedings of the National Academy of Sciences, 11 August 2020, Pages 19054-19060
Abstract:
Whose voices are most likely to receive news coverage in the US debate about climate change? Elite cues embedded in mainstream media can influence public opinion on climate change, so it is important to understand whose perspectives are most likely to be represented. Here, I use plagiarism-detection software to analyze the media coverage of a large random sample of business, government, and social advocacy organizations’ press releases about climate change (n = 1,768), examining which messages are cited in all articles published about climate change in The New York Times, The Wall Street Journal, and USA Today from 1985 to 2014 (n = 34,948). I find that press releases opposing action to address climate change are about twice as likely to be cited in national newspapers as are press releases advocating for climate action. In addition, messages from business coalitions and very large businesses are more likely than those from other types of organizations to receive coverage. Surprisingly, press releases from organizations providing scientific and technical services are less likely to receive news coverage than are other press releases in my sample, suggesting that messages from organizations with greater scientific expertise receive less media attention. These findings support previous scholars’ claims that journalistic norms of balance and objectivity have distorted the public debate around climate change, while providing evidence that the structural power of business interests lends them heightened visibility in policy debates.
Temperature thresholds and the effect of warming on American farmland value
Emanuele Massetti & Robert Mendelsohn
Climatic Change, August 2020, Pages 601–615
Abstract:
Many studies suggest that warming is harmful to American crop yields because of a temperature threshold near 30 °C whereupon yields abruptly fall. This study uses a flexible daily temperature bin specification in a Ricardian model to measure the response of farmland value to daily temperature. The analysis does not find evidence that high temperatures are particularly harmful to farmland or cropland value in the Eastern United States. Instead, temperature has a smooth hill-shaped effect on farmland value with a peak temperature of about 18 °C. Nonetheless, the Ricardian model predicts that cropland values would fall linearly by 15%/°C with uniform warming, while farmland values of mixed farms would fall far less.
Current European flood-rich period exceptional compared with past 500 years
Günter Blöschl et al.
Nature, 23 July 2020, Pages 560–566
Abstract:
There are concerns that recent climate change is altering the frequency and magnitude of river floods in an unprecedented way1. Historical studies have identified flood-rich periods in the past half millennium in various regions of Europe2. However, because of the low temporal resolution of existing datasets and the relatively low number of series, it has remained unclear whether Europe is currently in a flood-rich period from a long-term perspective. Here we analyse how recent decades compare with the flood history of Europe, using a new database composed of more than 100 high-resolution (sub-annual) historical flood series based on documentary evidence covering all major regions of Europe. We show that the past three decades were among the most flood-rich periods in Europe in the past 500 years, and that this period differs from other flood-rich periods in terms of its extent, air temperatures and flood seasonality. We identified nine flood-rich periods and associated regions. Among the periods richest in floods are 1560–1580 (western and central Europe), 1760–1800 (most of Europe), 1840–1870 (western and southern Europe) and 1990–2016 (western and central Europe). In most parts of Europe, previous flood-rich periods occurred during cooler-than-usual phases, but the current flood-rich period has been much warmer. Flood seasonality is also more pronounced in the recent period. For example, during previous flood and interflood periods, 41 per cent and 42 per cent of central European floods occurred in summer, respectively, compared with 55 per cent of floods in the recent period. The exceptional nature of the present-day flood-rich period calls for process-based tools for flood-risk assessment that capture the physical mechanisms involved, and management strategies that can incorporate the recent changes in risk.
Return to rapid ice loss in Greenland and record loss in 2019 detected by the GRACE-FO satellites
Ingo Sasgen et al.
Communications Earth & Environment, August 2020
Abstract:
Between 2003-2016, the Greenland ice sheet (GrIS) was one of the largest contributors to sea level rise, as it lost about 255 Gt of ice per year. This mass loss slowed in 2017 and 2018 to about 100 Gt yr−1. Here we examine further changes in rate of GrIS mass loss, by analyzing data from the GRACE-FO (Gravity Recovery and Climate Experiment – Follow On) satellite mission, launched in May 2018. Using simulations with regional climate models we show that the mass losses observed in 2017 and 2018 by the GRACE and GRACE-FO missions are lower than in any other two year period between 2003 and 2019, the combined period of the two missions. We find that this reduced ice loss results from two anomalous cold summers in western Greenland, compounded by snow-rich autumn and winter conditions in the east. For 2019, GRACE-FO reveals a return to high melt rates leading to a mass loss of 223 ± 12 Gt month−1 during the month of July alone, and a record annual mass loss of 532 ± 58 Gt yr−1.
Extreme hurricane rainfall affecting the Caribbean mitigated by the Paris Agreement goals
Emily Vosper, Dann Mitchell & Kerry Emanuel
Environmental Research Letters, forthcoming
Abstract:
Hurricanes are among the most impactful extreme weather events affecting small island states such as the Caribbean and require long-term planning for community and infrastructure resilience. By coupling an offline dynamical hurricane model to the output of a large ensemble of global climate model simulations from the Half a degree of Additional warming Prognosis and Projected Impacts (HAPPI) project, we assess how the impacts of hurricanes may change under the Paris Climate goals. Specifically, we concentrate on hurricane rainfallover particular regions, with both the mobility and intensity of a hurricane being key drivers of local level impacts. For example, Hurricane Dorian (2019) caused widespread devastation when it stalled over The Bahamas as a category 5 storm. We show that since 1970 only one other hurricane stalled at this strength: Hurricane Mitch (1998). Due to a combination of increased stalling and precipitation yield under a warmer world, our analysis indicates a greater likelihood of extreme hurricane rainfall occurring in the Caribbean under both Paris Agreement scenarios of 1.5◦C and 2◦C Global Warming goals, compared to present climate projections. Focusing on specific hurricane events, we show that a rainfall event equal in magnitude to Hurricane Maria is around half as likely to occur under the 1.5◦C Paris Agreement goal compared to a 2◦C warmer climate. Our results highlight the need for more research into hurricanes in the Caribbean, an area which has traditionally received far less attention than mainland USA and requires more comprehensive infrastructure planning.
Hydrological limits to carbon capture and storage
Lorenzo Rosa et al.
Nature Sustainability, August 2020, Pages 658–666
Abstract:
Carbon capture and storage (CCS) is a strategy to mitigate climate change by limiting CO2 emissions from point sources such as coal-fired power plants (CFPPs). Although decision-makers are seeking to implement policies regarding CCS, the consequences of this technology on water scarcity have not been fully assessed. Here we simulate the impacts on water resources that would result from retrofitting global CFPPs with four different CCS technologies. We find that 43% of the global CFPP capacity experiences water scarcity for at least one month per year and 32% experiences scarcity for five or more months per year. Although retrofitting CFPPs with CCS would not greatly exacerbate water scarcity, we show that certain geographies lack sufficient water resources to meet the additional water demands of CCS technologies. For CFPPs located in these water-scarce areas, the trade-offs between the climate change mitigation benefits and the increased pressure on water resources of CCS should be weighed. We conclude that CCS should be preferentially deployed at those facilities least impacted by water scarcity.