The study looked at how future city growth in Melbourne could affect urban heat during heatwaves. By using computer models, researchers found that expanding urban areas could increase nighttime temperatures by up to 2.8°C in some parts of the city. This increase is due to changes in how heat is stored and released in the city. However, during the day, there were no significant changes in temperature between existing and expanded urban areas. Overall, the expansion did not impact human comfort levels in the city.