NASA: Global acreage burned by fire has dropped 24% since 1998

NASA detects drop in global fires

Shifting livelihoods across the tropical forest frontiers of South America, the Eurasian Steppe, and the savannas of Africa are altering landscapes and leading to a significant decline in the amount of land burned by fire, a trend that NASA’s satellites have detected from space.

The global area of land burned each year declined by 24 percent between 1998 and 2015, according to analysis of satellite data by NASA scientists and their colleagues. The largest decline was seen across savannas in Africa, and due to changing livelihoods. CREDIT Credits: Joshua Stevens/NASA’s Earth Observatory

The ongoing transition from nomadic cultures to settled lifestyles and intensifying agriculture has led to a steep drop not only in the use of fire on local lands, but in the prevalence of fire worldwide, researchers at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and colleagues found.

Globally, the total acreage burned by fires each year declined by 24 percent between 1998 and 2015, according to a new paper in Science that analyzes NASA’s satellite data, as well as population and socioeconomic information. The decline in burned lands was largest in savannas and grasslands, where fires are essential for maintaining healthy ecosystems and habitat conservation.

Across Africa, fires typically burn an area about half the size of the continental United States every year, said Niels Andela, a research scientist at Goddard and lead author on the paper. In traditional savanna cultures with common lands, people often set fires to keep grazing lands productive and free of shrubs. As many of these communities have shifted to cultivate more permanent fields and to build more houses, roads and villages, the use of fire declines. As economic development continues, the landscape becomes more fragmented, communities often enact legislation to control fires and the burned area declines even more.

By 2015, savanna fires in Africa had declined by 270,000 square miles (700,000 square kilometers) — an area the size of Texas.

“When land use intensifies on savannas, fire is used less and less as a tool,” Andela said. “As soon as people invest in houses, crops and livestock, they don’t want these fires close by anymore. The way of doing agriculture changes, the practices change, and fire slowly disappears from the grassland landscape.”

Andela and an international team of scientists analyzed the fire data, derived from the Moderate Resolution Imaging Spectrometer (MODIS) instruments on NASA’s Terra and Aqua satellites, as well as other sources. They compared these datasets with trends in population, agriculture, livestock density and gross domestic product.

The scientists found a different pattern in the rainforests and other humid regions close to the equator. Natural fires are rare in tropical forests, but as people settle an area they often burn to clear land for cropland and pastures. After the land is first cleared, as more people move into the area and increase the investments in agriculture, they set fewer fires and the burned area declines again.

The impact of human-caused changes in savannas, grasslands and tropical forests is so large that it offsets much of the increased risk of fire caused by warming global temperatures, said Doug Morton, a research scientist at Goddard and a co-author of the study. Still, the impact of a warming and drying climate is seen at higher latitudes, where fire has increased in parts of Canada and the American west. Regions of China, India, Brazil and southern Africa also show an increase in burned area. But the expansiveness of savannas and grasslands puts the global trend in decline.

“Climate change has increased fire risk in many regions, but satellite burned area data show that human activity has effectively counterbalanced that climate risk, especially across the global tropics,” Morton said. “We’ve seen a substantial global decline over the satellite record, and the loss of fire has some really important implications for the Earth system.”

Fewer and smaller fires on the savanna favors trees and shrubs instead of open grasslands, altering habitat for the region’s iconic mammals, like elephants, rhinoceroses and lions.

“Humans are interrupting the ancient, natural cycle of burning and regrowth in these areas,” senior author Jim Randerson, a professor of Earth system science at the University of California, Irvine, said of the African savannas. “Fire had been instrumental for millennia in maintaining healthy savannas, keeping shrubs and trees at bay and eliminating dead vegetation.”

There are benefits to fewer fires as well. Regions with less fire also saw a drop in carbon monoxide emissions and an improvement in air quality during the peak of the fire season, confirming the burned area trends using data from other NASA satellites. With less fire, the vegetation in savannas is also able to build up — taking up carbon dioxide from the atmosphere, instead of releasing it into the atmosphere during fires. The 24 percent decline in burned area may have contributed about 7 percent to the ability of global vegetation to absorb the increase in carbon dioxide emissions from burning fossil fuels and land use change.

The decline in burned area from human activity raises some difficult questions, Morton said: “For fire-dependent ecosystems like savannas, the challenge is to balance the need for frequent burning to maintain habitat for large mammals and biodiversity, while reducing fire on the landscape to improve air quality and protect people’s property and agriculture.”

As these savannas and grasslands continue to develop and agriculture intensifies, however, the researchers expect the global decline in fires to continue. It’s a trend that should be incorporated into computer models that forecast climate and carbon dynamics, Morton said.

“The loss of fire from agricultural landscapes has a big impact on communities and ecosystems. Looking ahead, models that account for changes in fire activity from human management will help us understand the feedbacks from fewer fires on vegetation, air quality and climate,” he said.


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June 30, 2017 2:48 pm

Apparently there is no relationship with global warming / climate change, since they are not mentioned. I thought everything that happened in the world was related to global warming / climate change.

Reply to  firetoice2014
June 30, 2017 3:44 pm

Not mentioning things is consistent with climate change!

Reply to  firetoice2014
June 30, 2017 3:45 pm

If you don’t mention the connection in the forest and no one hears it, does it still burn down?

Reply to  firetoice2014
June 30, 2017 3:59 pm

This is good news that can in no way be blamed on humans. So climate change is not mentioned. Everything that happens in the world, even if it happened many times in the past, is because of climate change and the only solution is for us peons to be poor, both in money and energy.

Reply to  firetoice2014
June 30, 2017 8:18 pm

Of course they mention climate change if you read the whole article….“Climate change has increased fire risk in many regions, but satellite burned area data show that human activity has effectively counterbalanced that climate risk, especially across the global tropics,” Morton said. “We’ve seen a substantial global decline over the satellite record, and the loss of fire has some really important implications for the Earth system.”

Gunga Din
Reply to  firetoice2014
July 1, 2017 9:22 am

Global warming / climate change wasn’t mentioned because has figured a way to spin a decrease in fires into something to defend the meme.
A possibility would be for them to use it to account for the fact that the Earth has greened as CO2 has increased. That fact doesn’t sound good to the climarmageddon promoters.
Maybe they’ll claim the greening isn’t due to CO2 but the war on tobacco? Fewer matches out there? 😎

Michael Jankowski
June 30, 2017 2:54 pm

Decline in burning = humans adjusting their lifestyles.
If there’d been an increase in burning, would that have been the explanation? Nah, it would’ve been global warming/climate change, like Morton says.

Andrew Burnette
Reply to  Michael Jankowski
June 30, 2017 3:06 pm

Good point.

Green Sand
June 30, 2017 2:56 pm

And how much has been chopped and shifted 3500 miles to be burnt in Yorkshire? The logic doesn’t just burn, it stinks of wallet lining

Andrew Burnette
June 30, 2017 3:10 pm

What happened in Northern Australia? Did you finally stop lighting kangaroo tails on fire?

Reply to  Andrew Burnette
June 30, 2017 3:31 pm

I hope not, that’s right up there with a dwarf toss for giggles. Seriously, I’d rather be shooting the excess kangaroos and dingos – more humane and requires skill.

Reply to  Andrew Burnette
June 30, 2017 4:17 pm

The situation in Northern Australia may be somewhat different to what the study claims this shows
From the article:-
“On October 1, 2015 a fire lit to manage weeds at the Ranger Uranium Mine burned through 14,000 hectares of Kakadu National Park, threatening important rock-art sites and closing several tourist attractions.
The Northern Territory Government and Energy Resources of Australia (the mine operators) are conducting enquiries to work out what went wrong and how to prevent similar accidents in the future, because like all natural disasters each one is an opportunity to learn.
As it happens, this fire coincided with the publication this month of my research that helps us to understand the problem posed by unplanned fires in the savannas of northern Australia.”
“My study used MODIS satellite mapping to examine the ignition date, duration and eventual size of 126,000 fires in Arnhem Land over a 10 year period. The largest fire ignited in late August 2004 and burned 445,000 hectares, 30 times the area burnt by the Ranger Mine or equivalent to a quarter of the size of Kakadu, our country’s largest national park.
But other regions have it worse: an accidental fire in the northern Tanami ignited on August 4 2011 burnt an area at least 5 million ha. There are 22 European countries smaller than that. So the Ranger Mine fire is in no way unique: it just happened to occur in a highly visible area.”

June 30, 2017 3:18 pm

Fire is a necessary part of some ecosystems. link I’m not even sure that having fewer fires is a good thing.

Reply to  commieBob
June 30, 2017 3:47 pm

The map shows more fire in central Canada. When I googled it the first thing that came up was the great forest fire of 1919! Missed it by THAT MUCH!

Reply to  commieBob
June 30, 2017 3:55 pm

It sure is in e. g. Madagascar where the fires have devastated most of the island. Little forest is left and erosion has reached catastrophic levels.

Reply to  tty
June 30, 2017 6:40 pm

Where I live, nature produces low intensity fires, which are good for the pine forests.
The USFS came along and suppressed little fires, so that fuel built up and more dry dead snags and deadfalls accumulated. Now the fires burn hot and spread far.
Dunno what happened in Madagascar.

Joe Crawford
Reply to  tty
July 2, 2017 1:29 pm

Back in the late 1950’s or early 1960’s I remember reading where Madagascar had originally been covered in triple canopy jungle. At that time the blame for loss of most of that jungle was placed on the goats left by early sailors: “Goat introductions on remote islands were once common practice—to provide food for shipwrecked sailors.”

Joe Crawford
Reply to  tty
July 2, 2017 1:31 pm

Sorry, the reference for that last line should be:

Reply to  commieBob
June 30, 2017 4:38 pm

I think the “good fire” meme is an urban legend . Maybe somewhere it makes seeds sprout but not here in Colorado . It leaves scars that last for decades .
I don’t question that it keeps grasslands grassland .

Tom Halla
Reply to  Bob Armstrong
June 30, 2017 5:36 pm

From what I know on the subject, it is the frequency of the fires, and therefore indirectly their intensity, that matters. If fire is suppressed long enough for the brush to get too dense, it will produce a much more intense fire, which can be destructive.

Reply to  Tom Halla
June 30, 2017 5:55 pm

I don’t think anything has changed in the intensity of fires . The notion of suppressing fires requires man to do the suppressing , and I think most of the mountain forests around here have never been affected one way or the other by man . I think the intensity of the fires has as much to do with the year’s weather as anything else . In years when it’s hot and scary dry like the year of the Waldo Canyon fire or the Hayman fire ( the area at the top of the image below ) the fires are intense and fast .
All of these burns happened before I moved out here a dozen years ago .

Tom Halla
Reply to  Bob Armstrong
June 30, 2017 6:02 pm

Fire suppression has been going on since the Europeans took over, most effectively since the late 1800’s.By most accounts, the Indians deliberately used fire as management of game as well as a hunting method.

Crispin in Waterloo but really in Ulaanbaatar
Reply to  Bob Armstrong
July 1, 2017 6:41 am

The First Nations can still demonstrate when to light a fire to make it rain.
I am in Mongolia at the moment. A piece in the paper reported flooding cause by heavy rain that lasted for three days, two weeks ago.
It also said that the rain had been arranged by the Weather and Meteorology Department!! Because of the importance of the Nadaam Festival on two weeks, they arranged to seed the clouds to get the grass green and long enough for the horse racing.
So it is still their tradition to initiate rain when the conditions are right. Light a huge grass fire is one good way to do that.

Dave in Canmore
Reply to  Bob Armstrong
July 1, 2017 7:06 am

Bob Armstrong: Rather than being a “meme” or urban legend, fire ecology is well understood and indeed in Colorado, the forest has evolved with fire. I’ve spent 25 years in the reforestation business and most forest managers in mountainous pine areas where I live can tell you the natural fire cycle is only 30-40 years! When suppression techniques delay this, fuel loads build and fire intensity does increase. These aren’t opinions, forest fuel loads are measured quantities carried out by land managers to assess the value of their forests and wildfire managers to assess fire danger ratings.
For a brief education on fire ecology in Colorado see the link below.

Reply to  Dave in Canmore
July 6, 2017 10:44 am

However it may be , these vast areas remain nearly barren with some deciduous scrub for on the order of decades .
My observation is that a core reason is lack of seed . I took some pictures of tree growth on our property , 39.038681° -105.079070° 2500m where the previous owners operated an ATV track until about the time of the Hayman fire , ~ 2002
. In this picture you see the saplings growing in the old ATV tracks near the trees . These tracks were bare like the bit you see in the front , but collected a blanket of cones .
Here’s a broader view showing the tracks of saplings and the more scrubby growth mixed in the foreground . The grass is much richer here than in the burn areas .
Clearly aggressively seeding , most economically from the air . maybe dropping little starter packets designed to stick in the terrain , but even just tearing apart cones and scattering the seeds , would massively accelerate the recovery of these naked lands to forest .

Bloke down the pub
Reply to  commieBob
July 1, 2017 3:05 am

Lightning will still trigger natural fires, and with a build up of woody material, those fires are likely to be more intense in future, especially as the local authorities are unlikely to have the resources to fight them. Probably a good thing, though it’ll obviously get blamed on cagw.

Tom Halla
June 30, 2017 3:25 pm

Living in an area that should be managed by fire (the Texas hill country), fire suppression can definitely be a bad thing. We have a problem with both cactus and Ashe Juniper (cedar) overgrowth, which should be controlled by fire.

Reply to  Tom Halla
June 30, 2017 5:41 pm

Cactus burns? (I googled it, it does burn.)
Anywhere I have lived is too far north to have much in the way of cactus other than a bit of opuntia fragilis so I have no direct experience. That said, I always thought succulents were a good way to protect your property from wildfire. link

Tom Halla
Reply to  commieBob
June 30, 2017 5:48 pm

Small cactus will get killed in a low grass fire, as will young Ashe Juniper, while reasonably mature oaks are not. The problem is getting a low enough fire.

Reply to  Tom Halla
June 30, 2017 6:33 pm

Re Tom Halla
June 30, 2017 at 6:02 pm
“Fire suppression has been going on since the Europeans took over, most effectively since the late 1800’s.By most accounts, the Indians deliberately used fire as management of game as well as a hunting method.”
I suspect that the Indians learned fairly quickly , as would have the Australian aborigines, that to protect themselves in a landscape subject to sudden and fast moving fires, they needed during times of high wildfire risk, to be on or near areas previously burnt in order to simply survive.

Tom Halla
Reply to  kalsel3294
June 30, 2017 6:44 pm

There are assertions that the Aborigines and many Indians deliberately burned off incipient brush to both make hunting easier and to enhance the population of the animals they hunted.

Reply to  kalsel3294
June 30, 2017 7:03 pm

In the case of Pacific NW Indians, it’s an observed fact.

June 30, 2017 3:27 pm

Outside the box: You know, it’s just possible the reason is because they’re running out of acreage to burn. “It could happen.”

June 30, 2017 3:39 pm

“Over last 20 years, annual fires in the US declined by about 50% while career firefighters increased more than 50%?”
Imagine how many firefighters there would be if there were no fires.

kokoda - the most deplorable
Reply to  richard
June 30, 2017 3:50 pm

50% more.

June 30, 2017 3:58 pm

It’s not clear whether the decline refers to an average year on year comparison for the time period or just the difference between that recorded for the year 1998 and the year 2015.

Dave Fair
June 30, 2017 4:26 pm

Well, they did include the obligatory “The impact of human-caused changes in savannas, grasslands and tropical forests is so large that it offsets much of the increased risk of fire caused by warming global temperatures …”
Can we see any observational studies that show an increased instances of fires related to increased global temperatures? We do know that incessant staring into climate model outputs will show pretty much anything you want, so those don’t count.

June 30, 2017 4:53 pm

How much acreage was cut down because the global advocacy focus has been on a trace gas instead?

June 30, 2017 6:37 pm

Since beneficial man-made CO2 has increased global vegetation by 30%, there should be more of it to burn.
But it hasn’t. Why is that?

Reply to  Gabro
June 30, 2017 6:59 pm

” beneficial man-made CO2 has increased global vegetation by 30%”

Do you have a citation for that ?

Patrick MJD
Reply to  Mark S Johnson
July 1, 2017 11:09 pm
June 30, 2017 7:09 pm

Having owned a SW Wisconsin dairy farm for several decades, a few ecological observations. The original land Ecology was prairie savannah. That meant periodic prairie fires dominated by tall ‘bluegrass’, with thick barked burr oaks able to withstand grass fires, plus box elders and cotton woods ( respectively very fast growing and very thick barked) softwoods along the bottom streams and creeks. Beavers loved eating boxelder bark.
Settlers came (my cabin/farm house dates from ~1888 hand hewn oak logs) in the 1870s. Killed all the wolves and cougars. Stopped all the prairie fires. So the ecosystem changed. All our highlands have dying old burr oaks, and all elsewhere red, black, white oak, plus hickory, maple, and black toothed aspen elsewhere. Coyotes have come in, but only one seasonal wandering wolf/coywolf pack in past decade.

Gary Pearse
Reply to  ristvan
July 2, 2017 2:21 am

Box Elder, I believe we called Manitoba maple? When I learned in primary school about folk back east making maple syrup, I tapped a whole bunch of different kinds of trees and boiled down the sap. It made a weird sort of toffee that only I seemed to have a taste for in the neighborhood.
It tasted better than the large blob of of petroleum tar I found along the railway tracks. The tar I broke into small pieces and sold to other kids for a penny a chew. It had a nice shiny black conchoidal fracture and chewed like gum. I suspect my better tasting tree toffee was thought to be poisonous, unlike my petroleum confection.

July 1, 2017 12:47 am

More greening. Less fires.

Peta from Cumbria, now Newark
July 1, 2017 2:27 am

Maybe there’s nothing left to burn.
Maybe the goats and people have eaten everything.
Maybe the people have cut the wood to a) Make ‘permanent’ houses b) to cook the goat-meat
But but but, goat does not *need* to to cooked to be edible.
For corn, wheat, rice, potatoes it is *essential* that they are cooked – totally indigestible otherwise. Its a process called, as it happens, ‘Processing’ and results in Processed Food.
How often do we hear how bad that sh1t is?
Not just for the fat & diabetic muppets that eat it either. It destroys the dirt that grew it
They mention ‘Permanent Fields’ – there is No Such Thing
No-one can repeatedly grow the same/similar crop on the same patch of dirt forever, Do not believe what the snake salesmen with their GM seeds, fertiliser & herbicide tell you.
Farmers in India, by good example, do swallow that guff. But after only 6 or 7 years of happy harvesting find suddenly, they have nothing left to do but use the pesticide on themselves. Thanks to the salesmen, the bankers, the lawyers, the well intentioned bureaucracy and all its cronies.
Meanwhile the Sputnik looks down on the neighbour’s field and everyone goes into raptures of delight because it is green.
It wasn’t yesterday and won’t be tomorrow but still the message is broadcast and repeated and sticks that We Are All Saved. Short term, shallow and unthinking.
Maybe Adam and Eve may have been able to light a fire in their little garden. Maybe not, rumour has it they found other ways of keeping warm..
But look at the place now, even Grenfell Council in London couldn’t start a fire there. Saddam and the US Army/Airforce had a damn good try but still failed.
As it ‘appens, sand doesn’t burn. Do NASA *really* need Sputniks and computers to work that out?
Any Faerie Counters in they house? Can *you* tell us?
Also, sheep, goats, camels and even people can’t eat sand and that, in the main, is why deserts are made of the stuff.

Steve Case
July 1, 2017 4:23 am
Crispin in Waterloo but really in Ulaanbaatar
July 1, 2017 6:30 am

“Humans are interrupting the ancient, natural cycle of burning and regrowth in these areas,” senior author Jim Randerson,
This statement is incorrect on two points: it was humans who were doing the burning all along and it was not ‘natural’.
Granted there are those who view ancient humans as ‘not human’, but I believe they were. Fire was used all over the world including the huge open areas free of trees in Northern Alberta which were managed into living memory. Blocking traditional burning in the lands west of Edmonton has resulted in a vast new forest of trees all the same height.
The story describes humans changing human behaviour and instead of seasonal burning, they are burning less and less. That is not ‘humans interrupting a natural cycle’. It was an unnatural cycle and it was humans who what dunnit. Now they are doing something else.
It seems to me the statement was crafted to make it sound as if ‘evil modern man’ is ‘breaking the natural system’ with new behaviours. Bunk! There was and is nothing natural about savanna burning. Occasional lightning strikes do not produce the seasonal fires in say, Botswana, Zambia, Swaziland and South Africa. They are routinely set by people who burn off the smothering dead grass from the dry season, after harvesting the needed roofing materials of course. Like the First Nations knew in N America, it can be timed to make it rain as well.
Humans are part of nature, dominate it, and maximize it’s productivity to the extent they can. May each of us do what we can to make the future sustainable, clean, intelligently managed and productive. We have everything we need to accomplish this.

Philip Bradley
Reply to  Crispin in Waterloo but really in Ulaanbaatar
July 1, 2017 6:17 pm

‘Bunk! There was and is nothing natural about savanna burning. ‘
Grasses evolved to facilitate fires in their competition with trees, long before humans came along.
That humans use this characteristic of grasses to set regular fires, doesn’t mean there are no natural fires. Here in Western Australia, most fires away from populated areas result from lightning strikes and typically burn for months. One fire in the 1970s burned for 2 years.
I’ll suggest this would be the natural pattern for most savanah and grassland areas, fewer fires that burn for much longer periods.

Rich Lambert
July 1, 2017 8:04 am

In north central Oklahoma the grasslands are being taken over by trees, particularly Eastern Red Cedar (a juniper). Many ranchers resort to controlled burns to kill the saplings. In some cases the burns are done by the local firefighters.

July 1, 2017 8:27 am

“Climate change has increased fire risk in many regions,”
The regions that are more green?

Dave Fair
Reply to  gymnosperm
July 1, 2017 10:40 am

Notice the word “risk?” Not “actual?” If you program your model well, it will tell you what you modeled.

July 1, 2017 11:41 am

@Anthony Watts, what document are you quoting from in your post? The link you gave goes to the homepage, and the first paragraph says,

Fires are an important source of atmospheric trace gases and aerosols and they are the most important disturbance agent on a global scale. In addition, deforestation and tropical peatland fires and areas that see an increase in the frequency of fires add to the build-up of atmospheric CO2.

The New York Times on June 23, 2017 published The Times’s Resident Expert for a World on Fire, and naturally it’s claiming we’re all going to hell in a handbasket.

Reply to  MRW
July 1, 2017 12:22 pm

You don’t need to answer. I just saw the correct link by Steve Case July 1, 2017 at 4:23 am.

Gary Pearse
July 2, 2017 1:56 am

I deliberately looked for mention of the effect of rapid greening both reducing the fires AND promoting land use change towards more intensive agriculture (trend toward the behavior in tropical land use with enhanced growth). I’m only a geologist and engineer and why should I be able to instruct these researchers on this subject? It is a reliable test of the political spin by scientists.
Note they are reluctant to mention anything good that mankind does, so they have to balance a too obvious good with how bad we are making it for “iconic” animals by NOT burning the hell out of lands! Sheesh this même is going to take root hooks to rip out of our civilization.

Istvan Marko
July 4, 2017 9:41 pm

Fires can have positive effects on other things than Savannah. As far as I remember, Giant sequoia trees will only reproduce after a fire; the seeds growing after partial burning. What would be interesting, though, would be to know what is the amount of particules (aerosols) decrease in the atmosphere due to this lowering in the number of fires worldwide since the last 30 years or so, and what is the impact of this decrease on the slight increase in the global average temperature of our planet over the same period of time. Has this parameter been taken into account in any of the currently used climate models?

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