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City dwellers at higher risk of heatwave death

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19 Feb, 2025

This post was originally published on Sustainability Matters

Mortality rates during heatwaves have been put in the spotlight with research from the University of Queensland (UQ) showing a 20% increase in heatwave-related deaths due to human-induced climate change.

Another UQ study has also revealed people living in cities are at a higher risk of dying from heatwaves than those in regional areas.

The two studies examined the mortality burden of heatwaves in Australia, and Associate Professor Nicholas Osborne from the School of Public Health hopes this research will assist communities and health authorities to prepare for extreme temperature events.

“Our results suggest heatwaves with associated periods of higher mortality will occur more often than they did in the past,” Osborne said.

“These higher mortality rates associated with extreme temperature heatwaves are projected to continue and we hope our research will help communities be better prepared for heatwaves.”

Heatwave risk for those living in cities

In one study, UQ researchers analysed two decades’ worth of temperature and mortality data to determine which areas in Australia are more vulnerable to heatwaves, through a Heatwave Vulnerability Index.

PhD candidate Patrick Amoatey from the School of Public Health said the study — the largest of its kind conducted in Australia — found people living in cities were at higher risk of death during extreme temperature events.

“We used an index mapping tool to assess how human populations will fare under a range of heat scenarios,” Amoatey said.

“We found the Heatwave Vulnerability Index, frequently used in other countries, could reliably predict heatwave-related deaths in Australia.

“In analysing data for more than 2000 suburbs, we found city dwellers with low income, low education, diabetes and limited access to health services, were at the highest risk of heatwave-related deaths.

“This was the case for all of Australia’s capital cities, which are home to 70% of Australia’s population.”

‘Heat island effect’

The researchers found that even during low-intensity heatwaves there was a strong association with deaths and the Heatwave Vulnerability Index in Australia’s capital cities.

“We believe the risk is higher in cities because of the ‘heat island effect’, as there are more heat-absorbing surfaces like roads, buildings and railway lines,” Amoatey said.

“In Greater London, for example, research has shown the Heatwave Vulnerability Index could be used to predict an increase in ambulance callouts and mortality rates during heatwaves, which is helpful for health authorities and something we could use in Australia.

“We already have useful tools and state-based action plans to reduce the impact of heatwaves, but we believe a vulnerability index could help supplement this to help communities plan and build resilience.”

Amoatey said a heatwave was considered a period of three consecutive days where the maximum temperature was in the top 5% for that area.

Climate change impacts on heatwave deaths

In a separate study, researchers from UQ and The Australian National University analysed mortality rates during an extreme heatwave in Victoria in January 2009, along with decades of climate data, to examine the impacts of climate change on heat-related deaths.

An estimated 374 excess deaths occurred in Victoria during the five-day event, with maximum temperatures reaching 12–15 degrees above normal.

“Human-induced climate change had increased the excess heatwave-related mortality in the 2009 event by 20%,” Osborne said.

“These findings were in line with other research that shows heat-related deaths are increasing due to human-induced climate change.

“From a public health perspective, our studies and further research can provide guidance on the need for adequate health infrastructure and workforce that might be needed to cope with higher demand for health services during heatwaves.”

The Heatwave Vulnerability Index research is published in Environmental Impact Assessment Review.

The mortality and climate change research was led by ANU’s Professor Sarah Perkins-Kirkpatrick and is published in Environmental Research Climate.

Image credit: iStock.com/Jay_Zynism

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Sustainability compliance should not be seen as a cost

Sustainability compliance should not be seen as a cost

The challenges of meeting new corporate sustainability reporting requirements are creating concerns across industries, but Schneider Electric’s Lisa Zembrodt says organisations should focus on the positives of compliance.

Zembrodt leads Schneider Electric’s Sustainability Business division, which assists many of Australia’s leading corporations to increase energy efficiency, reduce costs, adopt renewables and map their energy transition pathway.

Speaking to corporate leaders at Schneider Electric’s Innovation Summit in Sydney, Zembrodt said there was too much negativity in current debates over energy and sustainability, including focusing on the complexity and costs of compliance.

“We should turn these perspectives around and look at the opportunities in companies understanding their energy consumption and processes and using technology to drive efficiency. With compliance should come cost savings.”

The new Australian Sustainability Reporting Standards are mandatory and comprehensive, described by ASIC chair Joe Longo as the biggest change to corporate reporting in a generation. They carry penalties for non-compliance and will be closely monitored by investors and stakeholders.

The requirements came into effect for major companies from January and will be gradually rolled out. It involves more than putting data into a report and committing to emissions cuts, said Zembrodt.

“It’s about understanding the impact that climate has on an organisation, its markets and its supply chain. It’s putting in place plans to mitigate the risks, adapt and take advantage of the opportunities.

“Many entities today don’t have a transition plan; simply by requiring a plan to be created, the laws encourage companies to act,” said Zembrodt. “Organisations can gain competitive advantage from complying with the standards and set their strategies to capture the opportunity.

“Sustainability Business has been advising our customers on many areas of energy and sustainability for over 25 years, globally we work with 40% of the Fortune 500, working on everything from ESG reporting and disclosures to decarbonisation strategies and their implementation.

“Improving energy and resource efficiency creates cost savings,” she said. “Investing in renewable generation, storage, microgrids and demand response ensures the security and resilience of power supplies and can reduce energy costs in the long term.

“We’re advising companies on how to be more efficient, how to eliminate the use of fossil fuels in their fleets and their operations and, of course, we advise on how to switch to renewables.”

She points out that new technology and the evolution of power generation create opportunities and risks around energy sourcing. The influx of renewable projects in Australia has made buying renewables much easier than it was a decade ago.

Increased scrutiny and knowledge of business operations can bring additional and unexpected benefits.

“We’ve found that management of energy and energy supply contracts brings cost savings — these are often low-hanging fruit,” said Zembrodt.

“In 2024 we identified $6.7 million of errors in energy invoices for our clients. There’s absolutely no reason any company should overpay for energy.”

She also observed the increasing pressure from stakeholders and investors to progress sustainability, with a real impact on a corporation’s capacity to raise capital if it was not seen to be taking a positive approach.

Zembrodt acknowledged the sometimes-contentious issue of carbon offsets and emphasised they should not be used by companies to avoid actual emissions reduction in their operations. Some organisations were rightly walking away from dubious, generic offset schemes, she said.

However, targeted and documented offset programs had a vital role to play in hard to abate sectors where it was impractical to immediately cut emissions, she said.

“In Australia, the government has put a requirement called the safeguard mechanism on the highest-emitting facilities to buy carbon offsets if they can’t reduce their emissions. We can help to ensure the offsets procured have a positive impact on people and ecosystems.

“Did you know we supported the Paris Olympics with carbon offsets? Part of this included choosing three projects to support through carbon offset purchase for the Paris Olympics. People at the equator are most affected by climate change, so projects in that region are incredibly impactful in a positive way and that’s where we focused our attention.

“The first is mangrove restoration in Senegal, which involved 350 villages and 100,000 people. The second is water well restoration in Rwanda, which gives people safe drinking water nearby but also means emissions from burning wood to boil water are reduced. The third project is a 50 MW solar farm in Vietnam.

“However, we urgently need real emissions reductions. While it is positively impactful that companies invest in gold-standard carbon offset projects, it cannot come at the expense of action to decarbonise.”

Zembrodt pointed to recent extreme weather events as demonstrating how critical taking action on emissions was. “We’ve just seen the Queensland and NSW coastlines buffeted by a major cyclone, while in LA, this year’s devastating bushfires caused an estimated cost bill of more than $250 billion. And it’s not just the physical damage; medical and social costs follow, and let’s see the impact on insurance costs.”

Across the nation, we need to electrify processes wherever possible, and maximise renewable generation, she said. Those electrified processes also need to be made as efficient and optimised as possible through digitisation, monitoring and AI.

“The time to act is now,” she said. “70% of emissions can be eliminated today with the technologies we already have available to us.”

Image caption: Lisa Zembrodt, Principal and Senior Director, Schneider Electric Sustainability Business.

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