Australia experienced its third hottest year on record in 2017. The ‘Angry Summer’ of 2016-17 broke more than 205 climate records across the nation, and included several intense heatwaves in January and February. In winter, over 260 records were broken once again across the country, with the winter of 2017 the hottest on record for maximum temperatures. Low rainfall records were also broken throughout the season, resulting, along with the high temperatures, in an early start to the bushfire season across much of New South Wales. Oceans around Australia recorded temperatures well above average through the year.
The ongoing, long-term trend of recordbreaking heat is increasing the frequency and destructiveness of many extreme weather events, with devastating impacts in Australia and elsewhere around the world. Early in 2017, the Great Barrier Reef suffered its second consecutive mass bleaching event as a result of prolonged high sea surface temperatures, while later in the year, Queensland and northern New South Wales experienced record high May-September forest fire danger index values.
Globally, intense monsoonal rains and consequent flooding in South Asia led to more than 1,200 deaths and left 40 million people displaced or affected. Within one month, a series of powerful, damaging hurricanes—Harvey, Irma and Maria – tore through the Caribbean and southern United States, leading to some of the most intense rainfall and winds ever recorded. Heavy rains in Peru led to landslides leaving 75 people dead and making tens of thousands homeless. Meanwhile, wildfires brought on by extreme heat and drought caused devastation across the Mediterranean, with Portugal worst hit. California was also hit by wildfires in October and December, leaving a trail of devastation across the state.
The record-breaking heat and its associated impacts are amongst the most prominent fingerprints of climate change and are primarily caused by the human emission of carbon dioxide from the burning of coal, oil and gas. Carbon dioxide and other greenhouse gases trap additional heat at the Earth’s surface and in the lower atmosphere, driving the trends of increasing heat and worsening extreme weather. Humandriven greenhouse gas pollution has been rising strongly since the mid-20th century. Rapid and deep reductions in the level of greenhouse gas pollution is the only way to slow and eventually halt the strong upward trend in global temperature and the trend towards more frequent and intense extreme weather events.