Humans causing climate change heat

2014-09-30 05:00
(Saeed Khan, AFP)

(Saeed Khan, AFP)

Multimedia   ·   User Galleries   ·   News in Pictures Send us your pictures  ·  Send us your stories

Washingtn - Heat waves last year in Asia, Europe and Australia were influenced by human-caused climate change, but not all extreme weather events could be linked to global warming, scientists said on Monday.

A total of 16 extreme events - including rain, flood, droughts and storms - were analysed in an annual report called, "Explaining Extreme Events of 2013 from a Climate Perspective," published by the Bulletin of the American Meteorological Society.

The events chosen for study do not represent the year as a whole, but rather those that had big impacts and were of scientific interest, said the peer-reviewed report, compiled by 92 scientists from around the globe.

The most certain link between extreme weather and the burning of fossil fuels - which spew carbon dioxide and contribute to mounting levels of greenhouse gases - was seen in Australia.

Five independent studies all found that human influence had substantially increased both the likelihood and severity of heat waves in that country.

"The results of the Australia study are rather striking," said Peter Stott, a co-editor of the report from the UK's Met Office Hadley Centre.

"They have actually shown that the chances of observing such extreme Australian temperatures in a world without anthropogenic climate change is almost impossible," he said.

Extremely hot summers in Japan, Korea and China last year were also made more likely by human-caused climate change, the report found.

In New Zealand, global warming "caused meteorological conditions that were more favourable for drought in 2013," it added.

Both natural climate variability and human-driven warming were found to be factors in Western Europe's hot and dry summer.

There was also evidence that human-caused climate change contributed to heavy, once-in-100-year rains in India in June 2013, the report said.

Uneven influence

However, not every extreme weather event was found to be influenced by climate change. In some cases, natural variability in climate was deemed the leading factor.

Scientists were unable to find any human influence on some storms, including the 2013 South Dakota blizzard, cyclone Christian in northwestern Europe, and an extreme snowfall in the Pyrenees.

"Given what we know today, it is a lot easier for us to associate heat extremes with human influence than it is with some of the other extremes," said Thomas Karl, head of climatic data at the National Oceanic and Atmospheric Administration.

The science of studying the links between climate change and extreme weather is continuing to advance, and more refined measurements are hoped for in the future, said Marty Hoerling, a co-editor of the report.

He said a broad range of weather patterns were affected by climate change, not merely heat waves.

"It is almost [taken] for granted that climate change is influencing all manners of weather events," Hoerling told reporters.

Not if, but how

"It is a question now that we are posing - not does it influence, but how does it influence?"

Regarding California's ongoing drought - the worst in the state's history - one research team led by Stanford University found evidence that atmospheric pressure patterns increased due to human causes.

But two other research groups said the influence on the California drought remained uncertain.

"A clear picture of how exactly long-term climate change impacted the California drought has yet to emerge from the papers that are in this particular report," said editor Stephanie Herring of NOAA's National Climatic Data Center.

The UN Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report has also found strong evidence for increases in some extreme weather events worldwide since 1950.

Read more on:    ipcc  |  australia  |  climate change  |  global warming

Join the conversation! encourages commentary submitted via MyNews24. Contributions of 200 words or more will be considered for publication.

We reserve editorial discretion to decide what will be published.
Read our comments policy for guidelines on contributions.
NEXT ON NEWS24X publishes all comments posted on articles provided that they adhere to our Comments Policy. Should you wish to report a comment for editorial review, please do so by clicking the 'Report Comment' button to the right of each comment.

Comment on this story
Comments have been closed for this article.

Inside News24

Traffic Alerts
There are new stories on the homepage. Click here to see them.


Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.

Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire network.


Location Settings

News24 allows you to edit the display of certain components based on a location. If you wish to personalise the page based on your preferences, please select a location for each component and click "Submit" in order for the changes to take affect.

Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.