Press Association: London needs more parkland and to plant more trees to combat predicted rises in summer temperatures, an environment chief said today. Mayor Boris Johnson’s environment adviser Isabel Dedring said climate projections showed average summer temperatures in London could be some 3.9C higher than today by 2080, and as much as 6C to 10C on the hottest days. The “urban heat island effect” in which buildings absorb and release heat, maintaining a higher temperature in cities than …