Heatwave Trends Accelerate Worldwide – More and Longer Heatwaves Since 1950’s

City Heatwave

The first comprehensive worldwide assessment of heatwaves down to regional levels has revealed that in nearly every part of the world heatwaves have been increasing in frequency and duration since the 1950’s.

The research published in Nature Communications has also produced a new metric, cumulative heat, which reveals exactly how much heat is packed into individual heatwaves and heatwave seasons. As expected, that number is also on the rise.

In Australia’s worst heatwave season, an additional 80°C of cumulative heat was experienced across the country. In Russia and the Mediterranean, their most extreme seasons baked in an additional 200°C or more.

“Not only have we seen more and longer heatwaves worldwide over the past 70 years, but this trend has markedly accelerated,” said lead author Dr. Sarah Perkins Kirkpatrick from the ARC Centre of Excellence for Climate Extremes.

“Cumulative heat shows a similar acceleration, increasing globally on average by 1°C-4.5°C each decade but in some places, like the Middle East, and parts of Africa and South America, the trend is up to 10°C a decade.”

The only heatwave metric that hasn’t seen an acceleration is heatwave intensity, which measures the average temperature across heatwaves. This is because globally we see more heatwave days and heatwaves are lasting longer. When the average temperature is measured across longer heatwaves any shifts in intensity are almost undetectable. Only southern Australia and small areas of Africa and South America show a detectable increase in average heatwave intensity.

The study also identified that natural variability impacts on heatwaves can be large at regional levels. This variability can overwhelm heatwave trends, so regional trends shorter than a few decades are generally not reliable. To detect robust trend changes, the researchers looked at how the trends had changed over multi-decade intervals between 1950-2017. The changes were stark.

For example, the Mediterranean, saw a dramatic uptick in heatwaves when measured over multi-decade spans. From 1950-2017, the Mediterranean saw an increase in heatwaves by two days a decade. But the trend from 1980 to 2017 had seen that accelerate to 6.4 days a decade.

The regional approach also showed how the trends vary. Regions like the Amazon, north east Brazil, west Asia and the Mediterranean are experiencing rapid changes in heatwaves while areas like South Australia and North Asia are still seeing changes but at a slower rate.

However, no matter whether these changes are rapid or slow, it seems inevitable that vulnerable nations with less infrastructure will be hit hardest by extreme heat.

“Climate scientists have long forecast that a clear sign of global warming would be seen with a change in heatwaves,” said Dr Perkins Kirkpatrick.

“The dramatic region-by-region change in heatwaves we have witnessed over the past 70 years and the rapid increase in the number of these events, are unequivocal indicators that global warming is now with us and accelerating. “This research is just the latest piece of evidence that should act as a clarion call to policymakers that urgent action is needed now if we are to prevent the worst outcomes of global warming. The time for inaction is over.”

Reference: “Increasing trends in regional heatwaves” by S. E. Perkins-Kirkpatrick and S. C. Lewis, 3 July 2020, Nature Communications.
DOI: 10.1038/s41467-020-16970-7

3 Comments on "Heatwave Trends Accelerate Worldwide – More and Longer Heatwaves Since 1950’s"

  1. Face reality folks, YOU’RE DOOMED! But then you folks can’t face reality so for sure you are DOOMED! You BOZOS keep flying gigantic VACUUM MACHINES called jet engine airplanes and rockets that SUCK UP AND THEN HEAT UP AND THEN POLLUTE our upper atmosphere where clouds are formed. Theses jet planes suck in enough air to fill a Astrodome size stadium in 2 minutes! If you were to stack the Astrodome stadiums on top of each other it would take about a stack of 43 Astrodome stadiums to reach the part of our atmosphere where clouds are formed. ALL of this sucked in air is heated up from 800 degrees to 1200 degrees for passenger airplanes. Military jet planes exhaust ranges from 1200 degrees to 2500 degrees! Rockets are much hotter! The Space Shuttle was as HOT AS THE SUN! ALL of these flying machines pollute our atmosphere with exhaust that contains many harmful ingredients that causes nature to not be able to combine the right ingredients in the atmosphere’s air to make clouds. Nature needs a certain level of moisture in the air to make clouds. When YOU DAILY suck out moisture from the atmosphere it leaves less moisture in the atmosphere to MAKE CLOUDS! And when you FACE REALITY you will realize that CLOUDS are NATURE’S ONLY way to provide the Earth with a shield of some kind to deflect the hot heat waves that emit millions of miles away from this great ball of fire we call the Sun! But you BOZOS constantly daily fly 90,000 of these polluting PASSENGER jet engine airplanes and who knows how many military planes, into our atmosphere where clouds are formed and fly them around for HOURS as YOU SUCK UP, HEAT UP AND POLLUTE OUR ATMOSPHERE! ALSO you BOZOS are flying who knows how many hotter military airplanes, rockets and weapons of all kinds which also adds to our heated atmosphere. Folks, with ALL the heat and pollutants that you have emitted over time into our atmosphere we have tipped the atmospheric moisture content balance that nature needs to produce CLOUDS AND RAIN and tipped nature into a weather pattern where nature can’t produce enough atmospheric moisture to create clouds and rain and instead now nature is geared to be so that since there is less clouds the Sun can now more easily reach the Earth’s surface and heat up our planet which causes nature to then enter a cycle where the Sun will evaporate water from the planet constantly but nature will only be able to produce a limited amount of clouds or no clouds in most areas. But these clouds won’t produce rain but instead will evaporate from the heat of he Sun. This is how planets turn from having moisture like Earth to not having moisture like Mars or Venus or other planets. So the combination of the jet planes and rockets have heated up our atmosphere since the 1960’s to the point where the weakest link in the Earth’s ice formations which is permafrost has been melting in mass since the 1960’s and that warmer melted permafrost water has been leaking into the North Pole’s ice region where it has since the 1960’s been melting the ice in the North Pole! As the WARMER melted water from the melted North Pole ice started circulating around the world since the 1960’s the oceans and the South Pole waters also started heating up. As waves gulped in more hot air the oceans heated up more. Also Humans cut down many trees around the planet. Trees are nature’s way of providing shade and natural cooling towers for the Earth. Trees also help nature create moisture in the environment. So all of this caused our planet to not be able to provide the environment for nature to perform as it did before the 1940’s. We have to IMMEDIATELY change that because once the North and South Poles ice has all melted as well as all the earth’s ice glaciers and snow covered mountains are gone this planet will be doomed into becoming a hell on earth as the Sun will then start the path of baking the Earth into looking like Venus!

    • Clyde Spencer | July 5, 2020 at 9:05 am | Reply

      Among many things, you said “So all of this caused our planet to not be able to provide the environment for nature to perform as it did before the 1940’s.” Such as the Dust Bowl era of the 1930s?

      Your rantings are that of one who knows enough to convince themselves that they understand the workings of the Earth. The problem is, you don’t know enough to know what you don’t know. You aren’t just detached from reality, you don’t know what reality is. Your rants are full of misconceptions and falsehoods.

  2. Clyde Spencer | July 5, 2020 at 8:27 am | Reply

    For another take on the Heat Wave issue, based on the same data source (BEST), see the following:

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