Climate Change, Physical Activity and Bike Share Usage
Heaney et al. investigate how rising temperatures due to climate change might impact outdoor bicycling, which is a form of physical activity that has demonstrated health benefits. In this study, the authors use New York City Citi bike data to better understand the relationships between population bicycling behaviors and ambient temperatures.
Biking as a form of transportation or leisure has been shown to have marked health benefits. Biking is dependent on climate factors such as weather and temperature, with several studies showing that as temperature increases linearly, so does biking. However, as climate modeling predicts the increase in ambient temperature, how will bike use change? Heaney et al. seek to address this question in their recent study of bikeshare use in New York City.
More than 10,000 Citi bikes are available throughout Manhattan, Brooklyn, and Queens and rides cost from $3 for half an hour to $12 for a day; yearly memberships in 2018 were $169. Heaney et al. accessed Citi bike data from between 2013 and 2017 and constructed a data set of 37 million rides. Specifically, Heaney et al. used the duration and distance of rides to measure daily bike usage. In order to determine the relationship between bike use and temperature, Heaney et al. accessed maximum and minimum ambient air temperature, precipitation, and relative humidity from the National Oceanographic and Atmospheric Administration (NOAA). Finally, in order to approximate how climate change would affect bikeshare use, Heaney et al. projected mean daily maximum temperatures for the period from 2040 to 2069 from 21 climate models under two hypothetical emission pathways.
Heaney et al. found that in general, Citi bike use increased with temperature, until a threshold of 28.1 degrees Centigrade/82.6 degrees Fahrenheit or 25.8 degrees Centigrade/78.4 degree Fahrenheit, depending on the outcome, was reached. Above 28 degrees C, bike use significantly decreased. Under the various climate change scenarios, they predicted a decline in summer bike usage by 2070 due to an increase in days with temperatures above the threshold of 28C. However, they predicted annual increases in bike usage by 2070 because the decline in bike usage during the summer would be smaller than increases in bike usage projected for the winter, fall, and spring. Heaney et al. note that future work should investigate the effects of continuing temperature increase after 2070, individual and social determinants of bike use behavior, and the effects of other climactic factors such as humidity or precipitation.
Heaney AK, Carrión D, Burkart K, Lesk C and Jack D. Climate Change and Physical Activity: Estimated Impacts of Ambient Temperatures on Bikeshare Usage in New York City. Environ Health Perspect. 2019 Mar;127(3):37002. doi: 10.1289/EHP4039