THIS STUDY EXAMINES how urban designinfluences the human experience of heat inPacoima, a neighborhood in the San FernandoValley region of Los Angeles. The primary metricfor heat exposure is Mean Radiant Temperature(MRT), which measures a variety of factors (e.g.,sun, surfaces, air, humidity, wind speed) thatcontribute to that experience, though we alsoexamine Land Surface Temperature (LST; anindicator for the “skin” temperature of the Earth)using estimates from satellite imagery.We find that the dominance of impervioussurfaces like buildings, parking lots and roads,as well as the scarcity of vegetative coverlike trees, shrubs and grass, contributes tohigh LST. In examining MRT using observedand simulated data to evaluate the humanexperience of heat, however, we find that theprimary factor in reducing heat burden is shade.Thus, areas of Pacoima that lack shade leavepeople vulnerable to extreme heat. This effect isespecially noticeable at Fernangeles ElementarySchool, which has less than 20% shade coveragethroughout the day and less than 10% shadecoverage during the midday recess period.Fernangeles Elementary is much hotter than itssurrounding residential neighborhood acrossall surfaces (grass, asphalt, concrete, rubber,soil) because it has so little shade. Both theschool and residential areas of Pacoima couldbenefit from increased shade but would also becandidates for a suite of interventions includinggreening, cool pavements and site-specificbuilding design.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Synthesizing trait observations and knowledge across the Tree of Life remains a grand challenge for biodiversity science. Species traits are widely used in ecological and evolutionary science, and new data and methods have proliferated rapidly. Yet accessing and integrating disparate data sources remains a considerable challenge, slowing progress toward a global synthesis to integrate trait data across organisms. Trait science needs a vision for achieving global integration across all organisms. Here, we outline how the adoption of key Open Science principles-open data, open source and open methods-is transforming trait science, increasing transparency, democratizing access and accelerating global synthesis. To enhance widespread adoption of these principles, we introduce the Open Traits Network (OTN), a global, decentralized community welcoming all researchers and institutions pursuing the collaborative goal of standardizing and integrating trait data across organisms. We demonstrate how adherence to Open Science principles is key to the OTN community and outline five activities that can accelerate the synthesis of trait data across the Tree of Life, thereby facilitating rapid advances to address scientific inquiries and environmental issues. Lessons learned along the path to a global synthesis of trait data will provide a framework for addressing similarly complex data science and informatics challenges.