Fires in the Amazon cause a host of environmental problems.
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By Claudio Angelo of Nature magazine
A group of scientists from Brazil and the United Kingdom are taking an unusual tropical field trip: 21 days flying in and out of heavy smoke plumes from wildfires in the Amazon and measuring everything they can, from the size of cloud droplets to the thickness of the aerosol column up to the stratosphere.
The goal is to understand how burning biomass in South America is affecting the local weather and air quality, and to close crucial gaps in climate models about how the process changes Earth’s radiation balance.
The SAMBBA (South American Biomass Burning Analysis) mission uses a four-engine jet airplane carrying a suite of instruments that can take measurements up to 12 kilometers above the canopy. Previous airborne campaigns used smaller planes and flew at much lower altitudes, so were unable to observe some crucial physical processes. “The Amazon is dominated by high-altitude convection clouds. If we don’t understand how they process energy and how fires interfere with them, we can’t make good weather predictions,” says Paulo Artaxo, a physicist and climate scientist at the University of São Paulo in Brazil, one of the scientists leading SAMBBA along with researchers from Britain’s Met Office, Brazil's National Institute for Space Research (INPE), the UK's Natural Environment Research Council and several British universities.
One of the instruments on board is a LiDAR, a laser that measures how much light is being blocked by aerosol particles from smoke at various altitudes. That local “dimming” of the atmosphere hampers photosynthesis, sometimes dramatically: local-scale measurements have shown decreases in plant productivity of around 30%. “We want to have an estimate for the whole Amazon”, says Artaxo.
More importantly, aerosols may actually produce cooling at the surface as well as warming at mid altitudes, says Karla Longo, a senior scientist at INPE and one of the 40 SAMBBA field researchers. Current models cannot account for such complex interactions, and therefore can’t accurately predict how increasing carbon dioxide concentrations and burning biomass will affect the radiation balance of the world’s largest tropical forest. “The very direction of the error signal in our models, whether it is towards warming or cooling, is hard to predict,” says Longo.
Ben Johnson, a member of the team from the Met Office, says that information on those aerosols is also important for improving global weather forecasts. “This is the first time we have measured biomass burning emissions from tropical forest with such comprehensive instrumentation.”
But SAMBBA will provide local benefits, too says Johnson. It is measuring substances that affect air quality in Amazonian cities, such as nitrogen oxides and other compounds that react to form polluting ozone at low altitudes. And ozone concentrations are known to be higher in the Amazon during the burning season than in the heavily polluted São Paulo metropolitan area. INPE has developed air-quality models that account for ozone and for particulate matter, but ozone-forming substances have never been measured before across the whole Amazon. One such compound, peroxyacetyl nitrate, was found in surprisingly high concentrations during SAMBBA’s first flights over Acre, in the Western Amazon. That kind of information will help to improve air-quality forecasting. “That result alone is worth the experiment,” says Artaxo.
This article is reproduced with permission from the magazine Nature. The article was first published on September 24, 2012.
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12 Comments
Add CommentLOL they believe that this is why GCMs are inaccurate???
Reply | Report Abuse | Link to thisI love the way you make these random leaps from one thing to another.
Reply | Report Abuse | Link to thisAnother recent article discusses what may be a more significant factor affecting global climate characteristics that is also not included in current models. Please see
Reply | Report Abuse | Link to thishttp://news.sciencemag.org/sciencenow/2012/09/stratospheric-winds-churn-up-the.html
Sisco, when you consider the record fire season this year, on a global scale, it would seem this is a very important portion of the data set. Especially when slash and burn agriculture is added in (the fact that so much of that goes to producing bio-fuel and animal protein is a mistake of tragic proportions.) Isn’t that how good science works, constantly evaluating parameters, striving to make your data set more accurate and complete?
Reply | Report Abuse | Link to thisBut then, based on posts by yourself and a few others it would seem that climatology is the one field of science in which predictive modeling cannot be applied. So it’s of no consequence that researchers are now going back and inputting actual measurements from a century ago, running their models, and using actual measurements made in the near past to verify these useless models. Even though the results are being found fairly accurate, this is climatology, you can’t use predictive models.
jtdwyer, I also saw that, surely that will soon be added to the portion of the data set encompassing ocean currents. But then to be “fair and balanced” we should “ditto” the assertion that it’s useless information because we can be sure that it was produced by members of a global conspiracy.
So If we were to decrease our emmisions from human
Reply | Report Abuse | Link to thisactivity by 25 per cent. How much would this actually
effect global warming given the amount of gases that are
produced by this and other natural phenomenon such as
the ring of underwater volcanoes that encircles the earth. We have no idea how much gas is emitted from this source,and...I don't hear it mentioned much. I suspect that it far exceeds what we as humans produce.
rodestar
Reply | Report Abuse | Link to thisVolcanism is a totally natural process; wildfire is sometimes natural, sometimes not. But your question is how much from each.
Volcanism at present, 130-230 megatonnes per year
Fire and decay, 439 gigatonnes per year (new growth at this time sequesters 450, 11 gigatonne negative)
What difference can we make?
252.4 million passenger vehicles in the US
18 lbs co2 per gallon of gasoline burnt
1 gallon per veh. = 4579 million lbs co2
Divided by 2000 (lbs per ton)
2.3 gigatonnes (1000 times the amount from volcanism) of co2 not produced by burning 1 less gallon of gasoline per passenger vehicle in the US. That is a pretty substantial number and it’s the result a minor conservation, so the argument that it would ruin our economy to have any effect is easily shown to be false.
Excuse me, that should be ten times more than volcanism not one thousand
Reply | Report Abuse | Link to thisThat's okay, we're used to gross exaggerations by the AGW side. You are excused.
Reply | Report Abuse | Link to thisCjoyce- "Sisco, when you consider the record fire season this year, on a global scale,"
Reply | Report Abuse | Link to thisSources please? I'm pretty sure this is no 'record year'.
cjoyce- I am an engineer who has been responsible for the development of large scale complex models. If it seems to you that I am stating that climatology is the one field of science in which predictive modeling cannot be applied, that would be an incorrect conclusion.
Reply | Report Abuse | Link to thisMy position is that developers of GCMs; as well as other models, should specifically publish what criteria their models are designed to accurately predict and within what margin of error at what timescales. Only those models that have demonstrated that they can make accurate forecasts should ever be used outside of the developers computers.
In the case of general circulation models I completely agree that the earth's climate is a very complex system that is currently not fully understood. In my personal opinion I am very skeptical of the concept of long term global general circulation modeling and believe that more accurate models could more easily have been developed if resources had been allocated to the development of regional models that would makes forecasts for less than 30 to 40 years. That type of model would have also been more useful for the development of government policy around the world.
In summary-do I think it is possible to model the climate accurately- answer yes, but it is a complex system and we currently do not fully understand how the system works and as a result the models do not current work well. Imo, formaion of government policy based on the output of a model that we know gives inaccurate reslts is stupid policy.
Do these forests burn without the trees being felled?
Reply | Report Abuse | Link to thisClean air is very important in the world we live in today . We actually have a lot air population mostly from factories and transportation . Such as public buses and hand made cars . Factories release a lot of chemicals in the air .
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