Modern Australian
Men's Weekly

.

The world endured 2 extra heatwave days per decade since 1950 – but the worst is yet to come

  • Written by Sarah Perkins-Kirkpatrick, ARC Future Fellow, UNSW

The term “heatwave” is no stranger to Australians. Defined as when conditions are excessively hot for at least three days in a row, these extreme temperature events have always punctuated our climate.

With many of us in the thick of winter dreaming of warmer days, it’s important to remember how damaging heatwaves can be.

In 2009, the heatwave that preceded Black Saturday killed 374 people. The economic impact on Australia’s workforce from heatwaves is US$6.2 billion a year (almost AU$9 billion). And just last summer, extreme temperature records tumbled, contributing to Australia’s unprecedented bushfire season.

What are heatwaves?

Our new study – the first worldwide assessment of heatwaves at the regional scale – found heatwaves have become longer and more frequent since 1950. And worryingly, we found this trend has accelerated.

We also examined a new metric: “cumulative heat”. This measures how much extra heat a heatwave can contribute, and the new perspective is eye-opening.

What is ‘extra heat’?

In southeast Australia’s worst heatwave season in 2009, we endured an extra heat of 80℃. Let’s explore what that means.

For a day to qualify as being part of a heatwave, a recorded temperature should exceed an officially declared “heatwave threshold”.

And cumulative heat is generally when the temperature above that threshold across all heatwave days are added up.

Let’s say, for example, a particular location had a heatwave threshold of around 30℃. The “extra heat” on a day where temperatures reach 35℃ would be 5℃. If the heatwave lasted for three days, and all days reached 35℃, then the cumulative heat for that event would be 15℃.

Another decade, another heatwave day

We found almost every global region has experienced a significant increase in heatwave frequency since 1950. For example, southern Australia has experienced, on average, one extra heatwave day per decade since 1950.

Read more: Anatomy of a heatwave: how Antarctica recorded a 20.75°C day last month

However, other regions have experienced much more rapid increases. The Mediterranean has seen approximately 2.5 more heatwave days per decade, while the Amazon rainforest has seen an extra 5.5 more heatwave days per decade since 1950.

The global average sits at approximately two extra heatwave days per decade.

The last 20 years saw the worst heatwave seasons

Since the 1950s, almost all regions experienced significant increases in the extra heat generated by heatwaves.

Over northern and southern Australia, the excess heat from heatwaves has increased by 2-3℃ per decade. This is similar to other regions, such as western North America, the Amazon and the global average.

Alaska, Brazil and West Asia, however, have cumulative heat trends of a massive 4-5℃ per decade. And, for the vast majority of the world, the worst seasons occurred in the last 20 years.

The world endured 2 extra heatwave days per decade since 1950 – but the worst is yet to come In the heatwave before Black Saturday, 374 people died. Shutterstock

We also examined whether heatwaves were changing at a constant rate, or were speeding up or slowing down. With the exception of average intensity, we found heatwave trends have not only increased, but have accelerated since the 1950s.

Don’t be fooled by the maths

Interestingly, average heatwave intensity showed little – if any – changes since 1950. But before we all breathe a sigh of relief, this is not because climate change has stopped, or because heatwaves aren’t getting any warmer. It’s the result of a mathematical quirk.

Read more: Climate change: 40°C summer temperatures could be common in UK by 2100

Since we’re seeing more heatwaves – which we found are also generally getting longer – there are more days to underpin the average intensity. While all heatwave days must exceed a relative extreme threshold, some days will exceed this threshold to a lesser extent than others. This brings the overall average down.

When we look at changes in cumulative heat, however, there’s just no denying it. Extra heat – not the average – experienced in almost all regions, is what can have adverse impacts on our health, infrastructure and ecosystems.

The world endured 2 extra heatwave days per decade since 1950 – but the worst is yet to come The Amazon has endured 5.5 more heatwave days per decade since 1950. Shutterstock

Like nothing we’ve experienced before

While the devastating impacts of heatwaves are clear, it has been difficult to consistently measure changes in heatwaves across the globe. Previous studies have assessed regional heatwave trends, but data constraints and the spectrum of different heatwave metrics available have made it hard to compare regional changes in heatwaves.

Our study has closed this gap, and clearly shows heatwaves are on the rise. We are seeing more of them and they are generating more heat at an increasing pace.

Read more: We've learned a lot about heatwaves, but we're still just warming up

While Australia may be no stranger to heatwaves in the past, those we see in the future under these accelerating trends will certainly be foreign.

For example, a 2014 study found that depending on where you are in Australia, anywhere between 15 and 50 extra heatwave days will occur by 2100 compared to the second half of the 20th century.

We can still abate those trends if we work collectively, effectively and urgently to reduce our greenhouse gas emissions.

Authors: Sarah Perkins-Kirkpatrick, ARC Future Fellow, UNSW

Read more https://theconversation.com/the-world-endured-2-extra-heatwave-days-per-decade-since-1950-but-the-worst-is-yet-to-come-141983

Refurbished iPads Are Better Than New Ones (Here's Why)

Image by rawpixel.com on Freepik Apple's refurbished iPad program has quietly become one of the best deals in tech. While everyone obsesses over the ...

Your Guide to Finding the Right GP: What Perth City Doctors Offer Today

Choosing a General Practitioner (GP) is one of the most important health decisions you’ll make. Luckily, Perth’s vibrant CBD now hosts a new ge...

Why Every Mining Operation Needs a Robust Safety Management System

Mining is one of the backbones of the Australian economy, particularly in Western Australia. Back in 2019-20, mining contributed 10.4% of Australia...

Australian Classic Literature Enjoys Resurgence

Welcome back to the good old days of storytelling! As the modern world becomes increasingly more demanding, returning to childhood favourites offers...

Building a Governance Model for Headless Content Management at Scale

Image by pch.vector on Freepik There's never been a better time to implement a headless content management system (CMS) to gain the flexibility and ...

Understanding Trade Insurance: Essential Protection for Businesses

Image by Drazen Zigic on Freepik In the current economic environment, trade insurance is an important element for companies trading both locally an...

Choosing the Right Timber for External Cladding

Timber cladding is one of those finishes that pulls double duty: it makes a building look warm and welcoming, and it quietly shields the frame from ...

Top Services Offered by Diesel Mechanics in Brisbane

Keeping a diesel vehicle running at its best takes more than the occasional oil change. When you invest in regular specialist care, you protect the ...

Top 5 Benefits of Hiring Professional House Removalists

Moving day should feel like the start of a new adventure, not the end of your patience. Yet once the settlement papers are signed and the champagne ...

Navigating the Digital Landscape: Managed IT Solutions and IT Services in Townsville

As technology advances at an unprecedented pace, companies must adapt to embrace the transformation ahead. With an evolving technology landscape, mana...

Types of Catering You Should Consider for Your Next Event

Choosing the right type of catering service can elevate your event from ordinary to unforgettable. Whether it’s an elegant wedding, corporate func...

Understanding the Benefits of Split System Installation for Your Home

Climate control is essential to maintaining comfort in your home, especially during the extreme temperatures that many regions face. Whether you’r...

Best Aluminium Window Sliding Designs for Natural Light and Airflow

Bringing natural light and airflow into a space is one of the most efficient ways to create a healthy and comfortable home. In Sydney and across Aus...

Maximising Operational Efficiency: Electric Winch Hire Australia and Hydraulic Power Pack Hire Solutions

Image by jcomp on Freepik From urban construction sites and remote mining operations to coastal maritime facilities, specialised equipment solutio...

Navigating the System: Your Guide to Support Finding Work with a Disability Around Melbourne

Image by freepik Finding the right job can be a challenge for anyone, but it can feel particularly daunting when you're also navigating life with a ...

Say Goodbye to Draughts and Hello to Savings: Your Guide to Perth Window Replacement

Image by prostooleh on Freepik Are your windows looking worse for wear? Are you paying a hefty power bill due to sneaky draughts and poor insulation...

How to Choose the Right Horse Trailer for Your Riding Needs

Many horse owners travel long distances for riding lessons, competitions, or to move horses between properties. Having a safe and reliable trailer i...

Sydney Turf Installer for Instant Green Lawns and Long-Term Performance

Having a green lawn at home makes everything look better. Whether it’s the front yard, backyard, or a small patch beside the driveway, people in S...