GREENING OUR LIVES
Seattle is not renowned for being hot. It’s a temperate, cloudy city on the West Coast of the United States, just south of the Canadian border. The Cascade Range lines its horizon, and above its skyscrapers hangs the always-white volcanic dome of Mt Rainier. As with Auckland, the waterfront meanders around harbours and waterways. Its average height-of-summer temperature is also familiar – about 25°C, cooling to 15 °C overnight.
On June 28, Seattle’s temperature reached 42°C. About 300km north, Canada’s hottest-ever recorded temperature of 49.6°C was being endured by the villagers of Lytton. Soon after, a wildfire engulfed the baked-dry village and residents had three minutes to evacuate their homes.
Seattle reached 42°C, and Canada recorded its hottest-ever temperature of 49.6°C in the village of Lytton.
The extreme temperatures were caused by a “heat dome” of warm air trapped underneath high atmospheric pressure, which in turn created heatwaves that killed hundreds of people and many millions of marine animals across the Pacific Northwest and western Canada and triggered devastating wildfires.
Climate change made it at least 150 times more likely to happen, according to scientists from the World Weather Attribution initiative, who described the temperatures as “uncharted territory”.
URBAN HEAT ISLANDS
The planet’s thermostat is rising uncomfortably. By 2050, Paris is predicted to be as hot as Canberra, and Edinburgh as warm as Paris. The same study suggests that Auckland will have Sydney-like temperatures. The National Institute of Water and Atmospheric Research (Niwa) predicts the annual number of days above 25°C will double in some New Zealand cities – 84% of the population live in urban areas.
Cities experience higher temperatures than rural landscapes because they are made of solid surfaces such as paving and roofs, which absorb and then slowly release heat. In addition, heat is generated by urban activities, such as running air conditioners.
This so-called “urban heat island” effect is considerable. Many US cities have air temperatures up to 5.6°C warmer than the surrounding
