Claim: Global warming to make more lightning caused fires, but only in the Southern Hemisphere

From PORTLAND STATE UNIVERSITY and the “global warming, is there anything it can’t do with the help of  interpreters” department:

Climate change increasing risks of lightning-ignited fires, study finds

Fires ignited by lightning have and will likely continue to increase across the Mediterranean and temperate regions in the Southern Hemisphere under a warmer climate, according to a new study co-led by a Portland State University researcher.

The study, published online in May in the journal Geophysical Research Letters, examined the observed and forecasted relationship between lightning-ignited fires, rising temperatures across the Southern Hemisphere and natural climate variability in three leading climate drivers that affect weather worldwide: El Niño-La Niña, the Indian Ocean Dipole and the Southern Annular Mode.

El Niño-La Niña, known as ENSO, is the periodic warming and cooling periods of the equatorial eastern and central Pacific Ocean that affects the world’s climate the most. The Indian Ocean Dipole, or IOD, is a similar ocean-atmospheric phenomenon characterized by changes in sea-surface temperatures between the eastern and western part of the Indian Ocean, while the Southern Annular Mode, or SAM, describes the north-south movement of the westerly wind belt that circles Antarctica and carries moisture to the southwest corners of all the Southern Hemisphere continents.

Heat, oxygen, fuel and an ignition source combine to start wildfires, but where and how quickly a fire moves depends on the terrain, the types and condition of vegetation present and the weather, said Andrés Holz, the study’s co-lead author and a geography professor in PSU’s College of Liberal Arts and Sciences.

The study found that of the three climate drivers, the SAM had the strongest impact on fire activity – both lightning- and human-caused wildfires – due to a combination of lower precipitation and higher temperatures, said Holz, who also serves as a faculty fellow at PSU’s Institute for Sustainable Solutions.

During the positive phase of SAM, the westerly winds contract toward Antarctica, leaving large areas in southern South America, South Africa and Australia rain-free. The recent positive trends in SAM are attributed to increasing greenhouse gas levels and the hole in the ozone layer.

“Now the winter is not as rainy and the summer is longer, drier and warmer,” Holz said.

Drier winters mean less moisture on the land, and warmer springs and summers are pulling the soil moisture into the air more quickly, allowing the soil and vegetation to dry out and ignite more readily, he said.

The study found that the natural influence of the three climate modes (ENSO, IOD and SAM) on fire activity was stronger during the 21st century than during the last couple of decades of the 20th century as a result of anthropogenic warming. That trend is expected to continue.

Among the study’s findings:

Global warming is linked to increased natural (lightning-ignited) fire occurrence

Climate change is amplifying climate-fire teleconnections, or the strength of long-distance relationships between weather patterns and fire During the onset of the 21st century, lightning-ignited fires were tightly coupled with upward trends in the SAM and rising temperatures across the Southern Hemisphere

“We think that by having warmer oceans and warmer temperatures in general, we’re going to see higher evaporation and heat transfer, and thus higher frequency of convective storms that in turn results in more lightning-ignited fires,” Holz said. “And with a climate mode such as SAM stuck in its positive, fire-prone phase that seems to amplify climate change, it doesn’t look good.”

But Holz cautions that it does not mean that there will be an increasing number of fires everywhere. Under warmer conditions, if precipitation stays constant, there will be increased fire activity in areas that already have plenty of fuel to burn but have historically been too humid or wet to burn. On the flip side, areas that are dry year-round will likely see a decline in fire activity with global warming unless there’s a strong increase in rainfall.

“These trends are expected worldwide, not just in the Southern Hemisphere,” Holz said.


The paper:

Climate Change Amplifications of Climate‐Fire Teleconnections in the Southern Hemisphere


Recent changes in trend and variability of the main Southern Hemisphere climate modes are driven by a variety of factors, including increasing atmospheric greenhouse gases, changes in tropical sea surface temperature, and stratospheric ozone depletion and recovery. One of the most important implications for climatic change is its effect via climate teleconnections on natural ecosystems, water security, and fire variability in proximity to populated areas, thus threatening human lives and properties. Only sparse and fragmentary knowledge of relationships between teleconnections, lightning strikes, and fire is available during the observed record within the Southern Hemisphere. This constitutes a major knowledge gap for undertaking suitable management and conservation plans. Our analysis of documentary fire records from Mediterranean and temperate regions across the Southern Hemisphere reveals a critical increased strength of climate‐fire teleconnections during the onset of the 21st century including a tight coupling between lightning‐ignited fire occurrences, the upward trend in the Southern Annular Mode, and rising temperatures across the Southern Hemisphere.

Plain Language Summary

This paper provides a critical view on the impending fire danger under increased climatic pressures, which is of extreme importance for the immediate future of climate change policy making and of landscape management and conservation actions. Our analysis of documentary fire records from across the Southern Hemisphere reveals, for the first time, a critical increased strength of fire‐climate teleconnections and a tight coupling between lightning‐ignited fire occurrences, the upward trend in the Southern Annular Mode, and rising temperatures during the onset of the 21st century. A clear increase in the potential for lightning‐ignited fires in response to climate change is an important reminder of the multitude of impacts that global warming will wreak on the Earth System.

NOTE: the title had a typo in it, accidentally switching northern and southern hemispheres. It has been corrected. – Anthony

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May 31, 2018 3:04 am

‘Heat, oxygen, fuel and an ignition source combine to start wildfires’
Really? What will they discover next?

Reply to  NorwegianSceptic
May 31, 2018 3:12 am

They will discover that most of the time “ignition source” is man-made (arson, carelessness), so much so that lightning caused fire cannot even happen any more, because someone did it before?

May 31, 2018 3:14 am

allowing the vegetation to get to massive levels by greetard agw-ist banning grazing in parks n high plains etc,,then add morons with matches
co2 isnt in the race

May 31, 2018 3:22 am

Use geoengineering to remove most of the CO2 ‘pollution’ and there will soon be no more fuel for the fires.
There – fixed!

May 31, 2018 5:01 am

The article talks about the Southern Hemisphere, but the title says Northern.

Reply to  jaxad0127
May 31, 2018 8:50 am

The *actual* article’s title says Southern Hemisphere. The blog title talks about Northern, although the blog itself never really justified the sarcasm. A little bit of twisting in an attempt to mock credibility before we can the actual article? Bias indeed…

[no, no mocking, just a simple typo, fixed -mod]

May 31, 2018 5:52 am

The titile seems contradictory. The main areas mentioned in the article are Mediterrean and temperate southern hemisphere regions.

Fires were ALL caused by lightning until people discovered how to keep small fires going and learned how to start new fires from scratch.

joe - the non climate scientist
May 31, 2018 6:48 am

Katheryn Hayhoe is even more impressive with her models, She has be able to model the weather and climate patterns for regions the size of the state of maine in the years 2050-2060 with impressive accuracy.

how about her study of precipitation in the state of Illinios
or climate change in Deleware

all peer reviewed

Alan Tomalty
Reply to  joe - the non climate scientist
May 31, 2018 7:05 am

My weather forecasters at Environment Canada should get her to forecast the weather in my city. Sometimes they put out a storm alert 6 hours ahead and the storm never happens. At other times they forecast the temperature 6 hours ahead and they end up being 3C off.

Farmer Ch E retired
Reply to  Alan Tomalty
May 31, 2018 7:18 am

Do climate scientists graduate from the same universities as weather forecasters? :<)

Alan Tomalty
Reply to  Farmer Ch E retired
May 31, 2018 7:45 am

To be fair to weather forecasters they have to rely on models for predictions. At least they don’t pressure governmental officials to put taxes on breathing like the climate scientists do.

Farmer Ch E retired
Reply to  Alan Tomalty
May 31, 2018 8:29 am

Fair enough. Which models are more accurate? Weather models or climate models?

Reply to  Alan Tomalty
May 31, 2018 8:32 am

Weather forecasters also have to deal with the initial values problem.
The better they know the current conditions, the better their forecasts become. The problem is that there aren’t enough sensors to know current conditions all that well.

Reply to  Alan Tomalty
May 31, 2018 8:42 am

The differences between weather and climate models are great enough that it isn’t possible to compare them.

Weather models, because they usually just try to forecast a small region are able to reduce their granularity, but still not enough. Weather models also need to know exactly what current conditions are so that they can be extrapolated forward. The less perfectly current conditions are known, the more quickly the forecast goes off the rails.

Climate models don’t care what current conditions are, so they can avoid that trap. Unfortunately for them, because they have to be able to model the entire earth, they have to greatly increase the size of their cells so that the computational requirements don’t become impossible. The larger the size of the cells, the more they have to parameterize rather than calculate from first principles.

Another difference is that changes that they have to be able to model long term changes.
For example, if increased rainfall changes the type of vegetation in an area, these changes will in turn modify the climate. Since weather models work for at most 5 to 7 days in the future, changes in vegetation aren’t large enough to matter.
This is the biggest reason why climate models are junk, everything affects everything, and we don’t understand the relationships well enough to model it.

I like to call this the 5 spheres.

A change in anyone of these “spheres” will impact the other spheres, which in turn cause changes in all the spheres, etc.

Some have suggested that I add the sun as a 6th sphere. However, while changes in the sun do impact the 5 spheres, changes in the 5 spheres don’t impact the sun.

Farmer Ch E retired
Reply to  Alan Tomalty
May 31, 2018 4:01 pm


“. . . everything affects everything, and we don’t understand the relationships well enough to model it.
I like to call this the 5 spheres.”

Is this like the 5th dimension? (not to be confused with the musical group)
More like one dimension beyond Einstein’s dimension of time. :<)

Alan Tomalty
May 31, 2018 6:52 am

No one can prove that a certain fire was caused by lightning unless a human observer happened to be right on the spot at the time. That being said , most estimates are that humans cause 90% of all wildfires with lightning and volcanic activity as the other 2 causes. They took data from 1950 . In one of the regions no lightning caused fire data was available. In another region in 3 parts of Australia the dataset did not include info on the source of ignition. Of the other 5 regions only 1 showed a clear increased trend of wildfires started by lightning. At least so far there has been no evidence except for Michael Mann of any climate scientists faking the actual data in their studies. However since most data on extreme weather events are in the public records, it would be easy to catch fake data for those types of studies. Let me repeat no dataset in the world shows any increase in extreme weather events despite this study’s claim. This study is bogus and is a prime example of junk science.

joe - the non climate scientist
Reply to  Alan Tomalty
May 31, 2018 7:20 am

Same with the increased hurricane intensity studies due to warming sea surface temps –

There has been a long term (150+ years ) trend of warming sea surface temps (since circa 1850) while
there has been a flat line trend in Hurricane intensity – yet somehow the climate scientists are able to “accurately” model / predict the change from the flat line trend to the upward trend in hurricane intensity.

Reply to  Alan Tomalty
May 31, 2018 8:43 am

It would be nice if they could find some evidence that the type of storms that create lightning are increasing.

Reply to  MarkW
May 31, 2018 12:50 pm

It would be nice if we could actually read the paper. I imagine that they could have managed to come up with a whole new statistical analysis which proves all of their bias. Just giving them the benefit of doubt. I mean, how else could they get the paper published???

May 31, 2018 6:53 am

I thought CO2 was used as a fire suppressant?

Johann Wundersamer
May 31, 2018 7:36 am

New acronyms “Indian Ocean Dipole, or IOD, is a similar ocean-atmospheric phenomenon characterized by changes in sea-surface temperatures between the eastern and western part of the Indian Ocean, while the Southern Annular Mode, or SAM, describes the north-south movement of the westerly wind belt”.

The lie staying Same As It Ever Was.

May 31, 2018 9:16 am

I don’t know if this is true or not, but there some people say they were behind the May 2016 Fort McMurray wildfire and others in US.

John Hardy
May 31, 2018 1:45 pm

I’m a bit confused here: the Med is northern hemisphere

ken morgan
Reply to  John Hardy
June 3, 2018 3:14 am

well i live in Australia and we dont know who to believe BOM said 3 days ago we are going to have a warmer and drier winter 3 days later it is going to be cold and wet ??????? ………

Reply to  ken morgan
June 3, 2018 3:58 am

” 3 days later it is going to be cold and wet “
No, they didn’t. Your second link is from 9 May, and they were then (accurately) predicting a few days cold wet weather, not even in winter.

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