Cloudy issues, burning answers: Jeremy Cherfas finds the best way to study the effect of fires on climate is to start one

ON 16 September, an ecologist will walk into the bush in the middle of South Africa's Kruger National Park and drop a match. The flames crackling across the veld will signal the start of an unusual project by the Southern Africa Fire-Atmosphere Research Initiative (Safari), a massive international effort to gather data on fires and how they affect the earth's atmosphere.

The man who will drop the match, Johann Georg Goldammer, is head of the Fire Ecology and Biomass Burning Research Group at the University of Freiburg in Germany, and co-chair of the Safari steering committee. He is also a driving force in what he calls 'global fire science', and at a recent meeting on fire and the environment organised by the Dahlem Konferenzen in Berlin, insisted that 'we must know the impact of biomass burning on world atmosphere'.

Why? Because vegetation fires fill the atmosphere with staggering amounts of chemicals: a quarter of the global carbon monoxide and nitrogen oxides, a third of the non-methane hydrocarbons, and a third of the ozone in the troposphere, along with many other reactive compounds. Are these pollutants, or integral parts of natural cycles? And if biomass burning - most of which takes place in the developing South - does prove to be a factor in global climate change, will that take the pressure off the developed North to clean up its industrial emissions?

Although there are good models for predicting the behaviour of fires, most have been developed to deal with the kinds of conflagrations that beset the North American timber industry. They are not much good for treating fires being used to clear rainforests, and almost useless for savannah fires.

For example, these models do not clearly distinguish between smouldering and blazing fires. As a fire spreads, it generally advances along a blazing front. Gases produced by the breakdown of the vegetation burst into flame, producing a preponderance of oxidised compounds and smoke, which absorbs sunlight.

Once the flame has passed by, the rest of the fuel smoulders, still burning, but without a flame. The products of a smouldering fire are different, producing more reduced compounds, such as methane, carbon monoxide, and smoke that is less light-absorbing.

Those differences almost certainly imply great variation in the impact of smouldering and blazing fires on atmospheric chemistry and global climate, but nobody knows how much vegetation flames and how much smoulders.

Safari will try to find out the answer, at least for savannah fires, which are among the most common types of deliberate fire. Dr Goldammer says 1.5 billion hectares (3.6 billion acres) of savannah are 'waiting to be burnt' each year, because setting fire to range-lands turns the unpalatable dead thatch into fertiliser that encourages a flush of palatable and nutritious young growth for cattle and other grazers.

The interactions between these fires and atmospheric chemistry are intricate and far-reaching, many of them mediated by the hydroxyl radical. Hydroxyls oxidise important atmospheric pollutants, mostly in equatorial regions.

Paul Crutzen, an atmospheric chemist at Stockholm University, says: 'The hydroxyl radicals are nature's 'detergents' and the tropics her 'washing machine'.' Emissions from fires are cleaned up by hydroxyl radicals, but in the process they destroy those radicals. That, Dr Crutzen says, 'lowers the oxidative capacity of large regions of the atmosphere'. In other words, biomass burning uses up the detergent, leaving the washing machine unable to do its job properly.

Then there is ozone, created by light in the presence of oxides of nitrogen. Nasa scientists have detected excess ozone streaming out over the southern Atlantic during the burning season in southern Africa. Safari should help establish how much ozone these fires create, which will enable modellers to assess its impact on climate.

And of course there is no fire without smoke, which may actually be keeping the planet cooler by reflecting sunlight. Smoke also provides nuclei on which raindrops can condense, thereby altering local rainfall patterns.

Fires have many effects, says Dr Goldammer. They shift nutrients around, change ecosystems, and probably affect climate.

The big issue is whether any of this is of wider significance. Biomass burning has been going on for at least 300 million years, ever since there were plants on land to ignite. And people have probably been using fire for at least half a million years. 'What's new,' says Steve Pyne, a historian and anthropologist at Arizona State University West in Phoenix, Arizona, 'is that global climate is making regional fires a world problem.'

Dr Crutzen explains: 'There is much more biomass burning than there was 100 years ago, of that I am convinced absolutely. Fossil fuels are definitely a driving force on global climate, but biomass burning, that's a very young idea.'

That is why Dr Goldammer is so keen to take everyone with an interest, from fire ecologists to global modellers, on safari. Almost 60 scientists will take part, and although the disastrous droughts in southern Africa have required some scaling back - there just isn't enough vegetation to burn in some places - Safari remains ambitious.

On the ground, crews will study the amount and type of fuel available. They will measure the behaviour of the fires, while overhead, scientists in low-flying aircraft will sample emissions in the smoke plume. High-flying planes and balloon-borne instruments will extend the measurements and tracking, and the whole will be watched over by satellite-borne sensors. Later efforts will look at the impact of fires on plant nutrients and ecosystem changes.

The goal is an improved model that integrates fires, weather and climate. 'We would like a technologically and geographically seamless system,' says Dr Goldammer. Such a model would integrate satellite information about the amount of fuel with recent weather information, to predict the risk of fire. It would also calculate the effects on the atmosphere of fires spotted from space.

(Photograph omitted)

Start your day with The Independent, sign up for daily news emails
ebooksA celebration of British elections
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

SThree: Trainee Recruitment Consultant - Dublin

£13676.46 - £16411.61 per annum + OTE: SThree: SThree Trainee Recruitment Cons...

Ashdown Group: Marketing or Business Graduate Opportunity - Norwich - £22,000

£18000 - £22000 per annum + training: Ashdown Group: Business and Marketing Gr...

SThree: Trainee Recruitment Consultant

£20000 - £25000 per annum + Commission: SThree: Are you great at building rela...

Ashdown Group: Database Analyst - Birmingham - £22,000 plus benefits

£20000 - £22000 per annum + excellent benefits: Ashdown Group: Application Sup...

Day In a Page

Fishing for votes with Nigel Farage: The Ukip leader shows how he can work an audience as he casts his line to the disaffected of Grimsby

Fishing is on Nigel Farage's mind

Ukip leader casts a line to the disaffected
Who is bombing whom in the Middle East? It's amazing they don't all hit each other

Who is bombing whom in the Middle East?

Robert Fisk untangles the countries and factions
China's influence on fashion: At the top of the game both creatively and commercially

China's influence on fashion

At the top of the game both creatively and commercially
Lord O’Donnell: Former cabinet secretary on the election and life away from the levers of power

The man known as GOD has a reputation for getting the job done

Lord O'Donnell's three principles of rule
Rainbow shades: It's all bright on the night

Rainbow shades

It's all bright on the night
'It was first time I had ever tasted chocolate. I kept a piece, and when Amsterdam was liberated, I gave it to the first Allied soldier I saw'

Bread from heaven

Dutch survivors thank RAF for World War II drop that saved millions
Britain will be 'run for the wealthy and powerful' if Tories retain power - Labour

How 'the Axe' helped Labour

UK will be 'run for the wealthy and powerful' if Tories retain power
Rare and exclusive video shows the horrific price paid by activists for challenging the rule of jihadist extremists in Syria

The price to be paid for challenging the rule of extremists

A revolution now 'consuming its own children'
Welcome to the world of Megagames

Welcome to the world of Megagames

300 players take part in Watch the Skies! board game in London
'Nymphomaniac' actress reveals what it was really like to star in one of the most explicit films ever

Charlotte Gainsbourg on 'Nymphomaniac'

Starring in one of the most explicit films ever
Robert Fisk in Abu Dhabi: The Emirates' out-of-sight migrant workers helping to build the dream projects of its rulers

Robert Fisk in Abu Dhabi

The Emirates' out-of-sight migrant workers helping to build the dream projects of its rulers
Vince Cable interview: Charging fees for employment tribunals was 'a very bad move'

Vince Cable exclusive interview

Charging fees for employment tribunals was 'a very bad move'
Iwan Rheon interview: Game of Thrones star returns to his Welsh roots to record debut album

Iwan Rheon is returning to his Welsh roots

Rheon is best known for his role as the Bastard of Bolton. It's gruelling playing a sadistic torturer, he tells Craig McLean, but it hasn't stopped him recording an album of Welsh psychedelia
Morne Hardenberg interview: Cameraman for BBC's upcoming show Shark on filming the ocean's most dangerous predator

It's time for my close-up

Meet the man who films great whites for a living
Increasing numbers of homeless people in America keep their mobile phones on the streets

Homeless people keep mobile phones

A homeless person with a smartphone is a common sight in the US. And that's creating a network where the 'hobo' community can share information - and fight stigma - like never before