Urban plant growth can survive climate change if cities build slowly enough, study finds

A new study from AGU finds that cities can maintain or even increase plant productivity despite development, but only if they build slowly enough. Researchers identified a critical speed limit: cities converting more than about 5.83 square kilometers of land to impervious surfaces per year saw plant productivity decline. Slower building allowed climate benefits like warmer air and higher CO2 to offset the loss of green space. The study looked at urban plant communities from 1982 to now and found that the offset effect varies by climate. For planners, this means the pace of development matters as much as the amount. Slower expansion lets remaining vegetation benefit from longer growing seasons and reduced water stress, keeping cities cooler and cleaner. Most cities currently build too fast to see this benefit, but the finding gives a clear target for urban growth policy tied to climate resilience.