Projections of Temperature and Precipitation in CMIP6 in Populated Cities in North America

Abstract

Climate change in the future will be intensified unless significant actions are taken to reduce or capture anthropogenic emissions. This paper uses the recently released CMIP6 simulation data to characterize specific changes in temperature and precipitation expected to take place in 28 populated cities in North America. This practice is based on examination of temperature and precipitation in four periods defined as historical, present day, near-future, and far-future. I first evaluate city-level estimations from CMIP6 with a reanalysis data from ERA5-Land for the present day. I then characterize spatial and seasonal changes in annual and monthly temperature and precipitation in the near and far-future for the 28 cities under SSP-585. Annual mean and maximum temperatures increase in all cities, while the annual minimum temperature shows the same trend but with some exceptions. The comparison across the four periods suggests an acceleration of warming in the second half of the century. Annual precipitation, however, shows an intensification in increasing maximums and decreasing minimums in many cities examined in this study, indicating higher risk of both droughts and extreme precipitation. I discuss the implications of the projected changes in terms of occurrence of extreme events, human health, and the loss and distributional effect in future economic development of the cities. Overall, significantly higher adverse impacts are expected, and the income gap between southern and northern cities will likely be widened. These findings provide city-level implications of climate change in North America for decision-makers.