Climate change in cities due to global warming and urban effects

TLDR

Urbanisation will bring 6 billion people to cities by 2050, exposing them to global climate change and localised urban heat island effects. The study incorporates an urban land‑surface model into the HadAM3 global climate model. The model shows that high population growth regions overlap with high urban heat island potential, especially in the Middle East, Indian sub‑continent, and East Africa; climate change can increase urban heat island potential by up to 30 % in some areas while reducing it globally by 6 %; and warming and extreme heat events driven by urbanisation and energy use can match the impact of doubled CO₂ in some regions, widening the disparity in extreme hot nights between rural and urban areas.

Abstract

Urbanisation is estimated to result in 6 billion urban dwellers by 2050. Cities will be exposed to climate change from greenhouse gas induced radiative forcing, and localised effects from urbanisation such as the urban heat island. An urban land‐surface model has been included in the HadAM3 Global Climate Model. It shows that regions of high population growth coincide with regions of high urban heat island potential, most notably in the Middle East, the Indian sub‐continent, and East Africa. Climate change has the capacity to modify the climatic potential for urban heat islands, with increases of 30% in some locations, but a global average reduction of 6%. Warming and extreme heat events due to urbanisation and increased energy consumption are simulated to be as large as the impact of doubled CO 2 in some regions, and climate change increases the disparity in extreme hot nights between rural and urban areas.