This is a wildfire near the China-Russia border inside Amur Oblast (49.4N 129.7E) on 7 May 2020. The fire is about 15 km x 10 km. This incredible image demonstrates the power of ‘false-colour’ composites for visualising satellite data. What does it show?
In the ‘true-colour’ image below, you might not notice that there is a fire raging on the ground. There’s a dark patch of land shrouded by clouds. This is how it would look to the human eye, if you were taking a ride on the satellite.
For the ‘false-colour’ image, we can visualise wavelengths of light that are invisible to the human eye. Short-wave infrared light reflected by plants is shown as green in this image, enabling a strong contrast between the live vegetation and the dead burnt vegetation.
Infrared energy from the intense heat of the fire show up as shades of red and orange. Some of the heat from the wildfire is so intense that it causes a glaring effect, like taking a photograph of the sun.
Sunlight reflected by the clouds shows up as a shade of blue. While the pink clouds are being illuminated from below by the heat from the fire!
This visualisation is built-in to the Sentinal-Hub EO browser as the false colour combination using Bands 12, 11, and 4 from the Sentinel-2 satellite. I processed the image further using photography software. Explore the imagery for yourself here.
Richard Feynman was an inspiring science communicator. In one of his television broadcasts [embedded below], he talks about a log burning on an open fire and provides one of the most eloquent explanations of the physical chemistry of wood combustion [full video and transcript below].
Feynman explains that throughout its life, a tree accumulates a great amount of potential energy in the form of carbon stripped by photosynthesis from its preferred molecular partner oxygen thanks to energy from the sun – that at a tree grows from the air, and not from the ground. It is only once it is provided with a source of ignition that carbon atoms in the tree and oxygen atoms in the air gain enough energy to reunite, a process that releases a great amount of energy, sustaining high temperatures and producing a chain reaction that is a fire. As Feynman put it, “the light and heat that’s coming out, that’s the light and heat of the sun that went in. So it’s stored sun that’s coming out when you burn a log!”
An interpretation of Feynman’s discussion is that combustion re-balances the imbalance caused by photosynthesis. The carbon that was taken from the atmosphere, and the energy that was taken from the sun by the tree, is quickly released back to the atmosphere during a fire – a closed cycle, where the regrowth of a new tree begins the process once again. If we extend this interpretation to the burning of ancient and fossilised carbon stores, such as peat, coal, oil, and gas; we can appreciate that the energy released comes from sunlight that once shone down on our planet many thousands or millions of years ago.
In a separate post on ‘Why wildfires fuel climate change’, I discuss how this natural component of the carbon cycle has been tipped far from equilibrium by human activity.
This video shows a brief walk through of one of our Trocari field sites near Sungai Besar, North Selangor, Malaysia. This site was once part of the Raja Musa Forest Reserve, but was illegally deforested ~15 years ago. Since then, the site has been drained and burned a number of times for land clearance and conversion to an oil palm plantation around 3 years ago (2015).
The video shows evidence of the burning, loss of ~1 m of peat soil profile, drainage, and the young oil palm trees. The converted side of the drainage canal is quite dramatically at a lower elevation than the forested side, with considerable loss of elevation due to peat fires, decomposition, and compaction.
It also ends showing the rather precarious bridge onto the site. Quite tricky to negotiate when you’re carrying heavy and expensive scientific equipment.
This photo essay documents a trip made by UK firefighters, land managers, and researchers, to participate in a “Technical Fire Management” training course in Catalonia led by the GRAF bombers (‘bombers’ being Catalan for fire fighter), Catalonia’s highly skilled forest fire fighters.
The trip formed part of my work whilst leading a Natural Environment Research Council (NERC) funded Knowledge Exchange project that links wildfire academics with various Fire and Rescue Services in the UK. The main aim of the project was to incorporate cutting-edge wildfire research (for example, wildfire spread simulation models, unmanned aerial reconnaisance systems etc.) into the wildfire training programmes offered by UK Fire and Rescue Services.
Perhaps surprisingly, the UK Fire and Rescue Services respond to more than 60,000 wildfires annually, which is around one-third of all fire ‘call-outs’. Despite this, specialised training is only offered by a handful of Services. Opportunities for UK fire personnel to participate in ‘live’ training fires are rare due to the unpredictable British weather and strict restrictions on when land burning can take place. One solution in recent years has been to send UK fire fighters to undertake training abroad in places like Catalonia and Kruger National Park in South Africa.
In February, around 20 officers from six UK Fire and Rescue Services, two Danish fire fighters, a land manager and myself (a researcher) flew to Barcelona where we were picked up and driven to the GRAF bomber academy in the suburbs. And so began a tough week of learning, hard labour, and fire, of course.
A full photo gallery containing 75 photos from this campaign can be found here.
Before the first classroom exercises of the day, the training course participants walk across the parade for a ceremonial photo under the national flags of the participant countries. Possibly ironic that the Catalans had mistaken Northern Ireland for the Republic of Ireland!
The rainforest is being cleared and burned in Borneo. A majestic Meranti tree is close to the edge of the forest. As flames from the nearby fires rage closer to this ancient tree, water quickly evaporates from its leaves, transforming the foliage into dry fuel for the fire. When turbulent, convective winds within the canopy bring hot air to the immediate surroundings of our tree, long-chain cellulose molecules in the desiccated foliage begin to crack, producing hydrocarbon gases and solid char deposits; with a flash, the gases ignite, forming the flames of the fire.
This brief, catastrophic episode at the end of this tree’s life quickly rebalances a century of organic chemistry. Throughout its life, the tree had accumulated a great amount of potential energy in the form of carbon stripped from its preferred partner oxygen thanks to energy from the sun through photosynthesis. Once provided with a source of ignition, carbon atoms in the tree and oxygen atoms in the air gain enough energy to reunite, releasing a great amount of energy, sustaining high temperatures and producing a chain reaction that is a fire. As the great physicist Richard Feynman once put it, “the light and heat that’s coming out [of a log fire], that’s the light and heat of the sun that went in. So it’s stored sun that’s coming out when you burn a log!”
According to Feynman, one could explain that a forest fire is ‘recycled sunlight’, a natural component of the carbon exchange between the biosphere and atmosphere. After all, fire is endemic to many of our planet’s natural environments, essential for regeneration, fertilisation and germination of many plant species. But does all of this burning have any influence on our climate? Continue reading “Why wildfires fuel climate change”