Climate Change Worsens Western Sydney’s Urban Heat Island

Climate change is creating longer and more intense summers, worsening heatwaves, and droughts in Australia. The year 2023 is on track to becoming Australia’s hottest year yet.

A data analysis, “Impact of Accelerated Climate Change on Maximum Temperature Differences between Western and Coastal Sydney,” published in the journal MDPI on March 2023, shows that temperatures in Western Sydney suburbs are a full 5°C hotter than near the coast. The findings come from an analysis of temperature data from 1962 to 2021, which reveals that one in ten days in summer reached temperatures of 35.4°C or more in Western Sydney, compared to one in ten days exceeding 30.4°C for the coastal areas. One in 20 days reached 37.8°C or more in the west – the equivalent figure near the coast was 33.6°C.

Additionally, Western Sydney experiences far more intense summer (December–March) heat waves than coastal Sydney, with maximum temperatures exceeding those of coastal Sydney by up to 10 °C.

In the last 30 years, hot days have become more common in Western Sydney but not on the coast as coastal Sydney benefits from the cooler temperatures of the Tasman Sea compared to inland Western Sydney.

According to the study, the stark difference in temperatures between the Western suburbs and the coastal areas is attributed to these factors: poor development and its distance from the cool coastal sea breezes, and climate drivers like the El Niño and La Niña events, the difference in the Indian Ocean temperature between the Ocean temperature difference in Ocean temperatures between its eastern and western sides (Indian Ocean Dipole), and movement of winds and weather systems and sea-level air pressure between Tahiti and Darwin. 

The analysis findings highlight the worsening heat in Western Sydney compared to its Coastal areas.

Urban heat island

Suburbs in Western Sydney are also grappling with the phenomenon known as heat island, and climate change is exacerbating the problem. The area is home to more than 2.5 million residents, projected to grow by 400,000 more by 2030.

Urban sprawl in Western Sydney, its dense concentration of buildings and infrastructure made of concrete and asphalt, absorbs and retains substantial heat, creating a localised climate or microclimate in the area. Population growth and economic progress have increased the building and infrastructure in the area.

News.com.au also reports that dark-coloured roofs dominated the newer builds in the area because of their stylish and modern look, which became famous around 15 years ago. Black and grey roofs absorb and trap enormous amounts of heat from the sun, adding to the day and increasing air temperatures.

Soaring temperatures from the heat island also have escalated air conditioning demands, contributing to more heating.

Western Sydney also has higher unemployment and a more significant proportion of lower-income families, and the impacts of climate change will further widen this socioeconomic divide.

Addressing the heat

The Conversation reports that some local councils in the west, such as Blacktown, are already trialling heat refuges to reduce the growing risks for residents.

Longer summers due to climate change also increase the chances of longer heatwaves, droughts, and more intense wildfires, such as the 2019-2020 wildfire dubbed the Black Summer, one of Australia’s most catastrophic fire seasons.

The article notes that economic costs from extreme events in the country have more than doubled since the 1970s and that extreme events are five times more likely to displace Australians. Western Australia’s vulnerable populations, like children in the classrooms, the elderly, those with pre-existing conditions, and low-income households, are highly more susceptible to heat-related illness or deaths.