Climate change, climate justice and the application of probabilistic event attribution to summer heat extremes in the California Central Valley

Abstract

Probabilistic event attribution (PEA) is an important tool for assessing the contribution of climate change to extreme weather events. Here, PEA is applied to explore the climate attribution of recent extreme heat events in California's Central Valley. Heat waves have become progressively more severe due to increasing relative humidity and nighttime temperatures, which increases the health risks of exposed communities, especially Latino farmworkers and other socioeconomically disadvantaged communities. Using a superensemble of simulations with the Hadley Centre Regional Model (HadRM3P), we find that (1) simulations of the hottest summer days during the 2000s were twice as likely to occur using observed levels of greenhouse gases than in a counterfactual world without major human activities, suggesting a strong relationship between heat extremes and the increase in human emissions of greenhouse gases, (2) detrimental impacts of heat on public health-relevant variables, such as the number of days above 40°C, can be quantified and attributed to human Climatic Change (2015) 133:427-438 DOI 10.1007/s10584-015-1474-

Drought in a human-modified world: reframing drought definitions, understanding, and analysis approaches

“…Additionally, more information is needed on past histories of water use and the role of technology in current routines of water practice (Pullinger et al, 2013), tipping points in human water use (Mera et al, 2014), and the reasons for a lack of public awareness of environmental water demands (Dessai and Sims, 2010). Understanding the relationship between these factors is crucial to enhancing our understanding of drought.…”

“…Firstly, regime changes trigger methodological considerations, because they can result in detection of drought events that should otherwise not be classified as drought, such as earlier snowmelt resulting in a drought in the normal snowmelt period (Lehner et al, 2006;Van Huijgevoort et al, 2014). Secondly, ecological and societal systems might adapt to a changing normal situation, but it is unclear how fast these adaptations will take place and whether tipping points will be passed (Mera et al, 2014).…”

Advancing the interdisciplinary dialogue on climate justice

“…However, she extends the perspective by touching on related justice aspects such as compensation for the harms caused by climate change, introducing considerations of criminal justice into climate debates, and catastrophe ethics. The latter issues are closely tied to discussions breached upon by a number of other contributions to this special issue, such as Mera et al (2015); Thompson and Otto (2015); Huggel et al (2015), and Wallimann-Helmer (2015b) (see below).…”

“…However, with the rise of loss and damage as a policy mechanism, which is increasingly pushed in the international climate negotiations, several contributions in this issue add depth and substance to the emerging debate and examine from different perspectives whether, and to what degree, attribution can have a role in informing or supporting loss and damage policies. Mera et al (2015) contribute to this issue with a study on heat waves in California which have a disproportional impact on Latino workers. By means of probabilistic event attribution (PEA) they evaluate to what degree extreme temperatures in California can be attributed to anthropogenic climate change.…”

The rise in global atmospheric CO2, surface temperature, and sea level from emissions traced to major carbon producers

“…The analyses presented here could be extended to examine the contribution of emissions traced to major carbon producers to other impacts, such as historical increases in ocean acidification (Ekstrom et al 2015) or the mortality impacts from extreme heat and other extreme events (Otto et al 2012;Mote et al 2015;Mera et al 2015;Mitchell et al 2016).…”