Heatwaves: Longer, hotter and more common

Apr 02, 2013
Heatwaves: Longer, hotter and more common

(Phys.org) —Australia's summer heatwaves are lasting longer and have been increasing in number over the past 60 years, a UNSW study shows.

During the same six-decade long period, days 12 to 14 degrees above average have been appearing more frequently throughout the year.

That is the finding of a detailed new study of heatwaves in Australia by Dr Sarah Perkins from the UNSW Climate Change Research Centre, and the Centre of Excellence for Science.

If the trends continue, there is no doubt the recent hot summer is likely to be a far more common event in Australia's future.

"Heatwaves have been increasing worldwide but the trend is even more marked across large parts of Australia, which as a has warmed faster than the global average," says lead author, Dr Perkins.

"Not only are we seeing more heatwaves in Australia but trends are suggesting that the hottest temperatures recorded during heatwave events are rising faster than the overall for these events."

To achieve their results the researchers used a new classification method they developed for a recent global heatwave study. The method defines heatwaves as periods of three days or more where the temperatures fall into the top 10% of the hottest temperatures ever recorded for specific times of year.

By taking this approach, the researchers were also able to look beyond the summer months and detect periods of unusually throughout the year, which they have analysed at the global scale.

"Interestingly, the anomalous warming events during the cooler months revealed through our research were increasing faster than summer heatwave events," Dr Perkins says.

"This could have important impacts on agriculture, particularly for the production of ."

The research also revealed how heatwaves have changed in a variety of ways from one region to another. A few of these changes include:

  • The number of heatwave days in a year has increased across much of north and central Queensland; Victoria and the southeast area of South Australia.
  • In many of these places, the increase in the number of heatwave events corresponded to the increase in heatwave days. However, in Victoria and South Australia the number of individual heatwaves have barely changed while heatwave days have increased, suggesting the heatwaves in these two states are increasing in length if not in number.
  • The temperatures recorded on the hottest days during heatwaves continue to climb in every state across Australia with some regional exceptions in northern and central Australia. This trend of increasingly hot peak temperatures during has accelerated since 1971.
"The next stage of our research will be to model these trends into the future under enhanced greenhouse gas conditions. Understanding how these trends may change in the future will help Australians better adapt to changing heatwave conditions," Dr Perkins says.

Explore further: New research on Earth's carbon budget

More information: On the Measurement of Heatwaves, Journal of Climate 2012 ; e-View, journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00383.1

add to favorites email to friend print save as pdf

Related Stories

Temperature hits all-time record in Sydney

Jan 18, 2013

Temperatures in Sydney on Friday hit their highest levels since records began 150 years ago, after an Australian government agency warned of more frequent and intense heatwaves in the future.

Australian climate on 'steroids' after hottest summer

Mar 04, 2013

Australia's weather went "on steroids" over a summer that saw an unprecedented heatwave, bushfires and floods, the climate chief said Monday, warning that global warming would only make things worse.

Scientists study record-breaking 2010 heatwave

Mar 18, 2011

An international research team has compared the hot summers of 2003 and 2010 in detail for the first time. Last year’s heatwave across Eastern Europe and Russia was unprecedented in every respect: Europe ...

Heatwaves to move toward coasts, study finds

Aug 29, 2012

(Phys.org)—A new study by researchers at Scripps Institution of Oceanography, UC San Diego, suggests that the nature of California heatwaves is changing due to global warming.

South Europe cities 'face 50 days above 35 degrees'

Sep 04, 2012

The European Environment Agency (EEA) on Tuesday unveiled an interactive map indicating the heatwave risk for European cities six decades from now on the basis of likely global warming trends.

Mapping the heatwave toll

Jan 08, 2013

A study identifying those Australians who are most vulnerable to extreme heat will inform new ways to help communities manage the risks associated with heatwaves.

Recommended for you

New research on Earth's carbon budget

1 hour ago

(Phys.org) —Results from a research project involving scientists from the Desert Research Institute have generated new findings surrounding some of the unknowns of changes in climate and the degree to which ...

More, bigger wildfires burning western US, study shows

18 hours ago

Wildfires across the western United States have been getting bigger and more frequent over the last 30 years – a trend that could continue as climate change causes temperatures to rise and drought to become ...

User comments : 0

More news stories

New research on Earth's carbon budget

(Phys.org) —Results from a research project involving scientists from the Desert Research Institute have generated new findings surrounding some of the unknowns of changes in climate and the degree to which ...