Without strong climate action, forests on every continent will be highly flammable for at least 30 extra days per year by the end of the century – and this fire threat is far greater for some forests including the Amazon, according to our new study.
Our research into Nature Communications looked at 20 years of global satellite data to test the link between wildfires and vapor pressure deficit – a measure of the atmosphere’s power to suck moisture out of living and dead plants. You can think of it as the air’s ‘thirst’.
Our results indicate that forest fire is more likely if there is a certain level of vapor pressure in some regions. The type of forest determines the threshold.
Alarmingly, Climate ChangeThis is increasing the days that the planet crosses these critical thresholds. However, we can decrease the number wildfire days by urgently reducing global carbon emissions.
How a forest is made flammable
Wildfire is a unique phenomenon that has been around for thousands of years. Here are four key points The conditions are favorable for a forest fire:
- fuel: The leaves, branches and twigs that catch fire in a forest
- Fuel moisture: Does the fuel have enough moisture to burn?
- Inflammation: The spark that sets things off. lightningStrike
- Weather: Conditions such as high temperatures and strong winds that can help a fire spread.
These four processes are switches. For a fire to start, they must all be in the “on” state.
A forest that is dangerously flammable can be made safer by drying out the fuel. Indeed, Many ResearchersAre Locating LinksThere is a difference between vapor pressure deficits (VPD), and fire activity.
VPD refers to the difference between the amount of moisture in the air and the moisture the air can hold once it is saturated. When air becomes saturated, water can condense and form clouds or dew on the leaves.
The VPD of warmer air is greater because it can hold more water. The air is referred to as ‘thirsty’ when there’s more space between full and empty. This means that there’s more demand (thirst), for water from living and dead plants, drying them out.
This is a serious problem as global warming can be caused by climate change.
Climate change and fire days
More than 30,000,000 were analyzed Satellite recordsAnd a global climate datasetTo determine the maximum daily VPD for each fire, and every time it was detected.
We measured the relationship between VPD, fire activity and different forest types on each continent. We found that VPD and fire activity are strongly linked in many forests.
Our data shows that certain VPD thresholds are beyond which forest fires become more likely.
For example, in boreal forests (predominantly northern European and American coniferous forests), this threshold is 0.7–1.4 kilopascals (a unit of pressure). In subtropical and tropical forests such as the Amazon, the threshold rises dramatically to 1.5–4.0 kilopascals. This implies that the air in Sumatra and Borneo must be more thirsty to ignite fire than the spruce, pine and larch forests of Canada.
We examined both low- and very high-emissions. scenariosWe found that the risks of failing to reduce emissions are greater than they were previously thought.
If humanity continues to release greenhouse gas emissions unabated, the planet is expected to warm by around 3.7 °C by the end of the century. Our study shows that forests across the globe will see at least 30 additional days each year in this scenario of high emissions.
Under a lower-emissions scenario where global warming is limited to around 1.8 °C, each continent will still see at least an extra 15 days per year crossing the threshold.
The greatest increase in both scenarios will be seen in parts of tropical South America, including the Amazon, by the end the century. At least 90 extra days in a low emission scenario and at least 150 additional days in high-emissions scenarios will occur.
What are the potential risks?
Increased forest fires can have devastating consequences. This can lead to a disruption in the forest fires and possibly destabilizing the patterns of fire and regeneration. Carbon storageWe rely on forests to provide for. Indeed, Research from last yearThe Amazon rainforest’s role as a “carbon sink” (which absorbs even more CO) was clearly demonstrated2It releases) could be already in decline.
We can also expect more harmful effects on the health of our human beings From wildfire smoke. It is estimated that approximately one billion people live in the world. More than 330,000 peopleEach year, hundreds of people are killed by smoke inhalation. This could rise significantly by the end of the century, especially in the most densely populated regions of South Asia or East Africa.
The next project we will be pursuing in Australia, where VPD and climate change are more closely linked. We are also interested in forests and areas where VPD is not the primary driver of fire like in Japan and Scandinavia.
The reliable link between atmospheric dryness, forest fire risk, and many other regions has allowed us to develop better fire predictions at both short-term and seasonal scales. This could have significant benefits for those working on the frontlines in managing wildfire and fighting it.
The authors are grateful for the contribution of Shiva Khanal (Western Sydney University) to this article.
Hamish ClarkeSenior Research Fellow The University of Melbourne; Anne Griebel, Postdoctoral Research Fellow Western Sydney University; Matthias BoerHawkesbury Institute for the Environment. Western Sydney University; Rachael Helene Nolan, Senior research fellow, Western Sydney University?, and Víctor Resco de Dios, Profesor de ingeniería forestal y cambio global, Universitat de Lleida
This article was republished by The ConversationUse the Creative Commons license Please read the Original article.
