Curbing The Climate Crisis By Ending Wildfires: The Essential Role Of Aviation

By Brien Seeley M.D., President, Sustainable Aviation Foundation
Senior Fellow of UC Berkeley’s Institute of Transportation Studies (ITS)

Meeting climate goals by ending wildfires

Humans have coexisted with wildfires for much of our history, adapting with the assumption that wildfires are an unavoidable natural phenomenon like earthquakes or weather.

Today in the anthropocene age we are again adapting to wildfires with the realization that they contribute massive amounts of CO2 directly and indirectly to our atmosphere, hampering our ability to prevent catastrophic outcomes from global temperature rise.

Our foundation has undertaken a study of these CO2 contributions to understand the potential climate benefits of ending wildfires, and has developed a proposal to achieve that goal using cutting-edge aerial firefighting systems deployed at scale. Our proposal is both sustainable and ambitious, and yet eminently achievable with the right alignment of urgency and collective will.

Wildfire CO2 emissions and the climate crisis

A wildfire is an unplanned, uncontrolled, and unpredictable fire in an area of combustible vegetation. Wildfires emit CO2 directly as smoke, and in addition eliminate the natural photosynthetic sequestration of CO2 by the forests and grasslands that have been burned. This lost sequestration increases every year as wildfires burn new areas – Burned forests take more than 20 years to regrow to 50% of their pre-fire photosynthetic capacity, while burned grasslands take 4 years to do so. Recent boreal forest wildfires in the US, Canada, Australia, Brazil and Russia have made international headlines due to increased frequency and intensity, threatening climate goals and biodiverse habitats. 

The Sustainable Aviation Foundation (SAF) sought to better understand the net CO2 impacts of wildfires, given newly available data on global wildfires and net ecosystem exchange values for lost forests, grasslands, savannahs and other land-cover types. 

When the latest data on mean global wildfire burn areas over the 20-year period from 2000 to 2020 is cumulatively multiplied by their respective net ecosystem exchange values (NEE), a first-order calculation shows wildfires to be responsible for an astonishing 101 gigatonnes of atmospheric CO2 contribution in the year 2020 alone, compared to a world in which we had prevented wildfires. This figure includes both the CO2 contributed directly via wildfire smoke (2010 to 2020) and the 20-year accumulation of lost CO2 sequestration globally in 2000-2020 due to annual devastation of vegetation.

Cumulative global annual CO2 sequestration lost, in gigatonnes, due to fire damage. Includes  linear regrowth to 50% of original photosynthetic capacity. Smoke CO2 2010-2020 in green bars. Sources: Chen et al (BA) and Zhuravlev et al (NEE) 

This value is conservative for for a number of reasons — It only includes the most recent 20 year period during which we have accurate data for burn areas and NEE, and it only accumulates sequestration losses for the first 50% of the burned area’s regrowth period. These calculations are modeled upon linear rather than exponential regrowth. They also do not account for lost sequestration on large areas of land-cover that border the actual burn areas due to them getting covered with smoke, ash and other particulates.
This 101 gigatonnes of CO2 (indexed to the year 2000) will increase every subsequent year that wildfires burn, and the World Resources Institute estimates that wildfire frequency and severity could increase by more than 200% by 2050.

The cost of wildfire CO2

The implications of this data are stark and astonishing: While leading nations struggle to agree on how to curb CO2 emissions via energy transitions, global wildfires are causing 2.5x more atmospheric CO2 per year than the nearly 40 gigatonnes of annual CO2 emissions caused by all global use of fossil fuels by humans.

Put into economic terms, according to the US EPA, each gigatonne of CO2 emitted worsens global climate damage by $190 billion dollars. By that metric, our calculation of 101 gigatonnes of CO2 in one year caused by wildfires amounts to $19 trillion dollars in loss and damages, each year. 

This cost is real, and is corroborated. Kotz et al in their April 17, 2024 report in Nature detail the latest information on climate mitigation costs for already committed loss and damage, stating that “the world economy is [already] committed to an income reduction of 19% within the next 26 years independent of future emission choices… These damages already outweigh the mitigation costs required to limit global warming to 2 °C by sixfold.” 

Increased wildfire damage in the Western US has led several insurance companies to withdraw from the massive California insurance market, raising existing premiums and directly transferring the cost of future wildfire damage to homeowners and taxpayers. Attribution scientists are increasingly successful in applying tort law to hold individuals, corporations and government agencies liable for loss and damages due to their inaction in preventing fires and other environmental impacts. 

Despite this alarming data and steep costs, CO2 emissions caused by wildfires have generally been regarded by global climate summits as unavoidable natural events that are baked-in to planetary systems. 

Ending wildfires with aerial firefighting systems

We believe that wildfire CO2 contribution represents a huge opportunity to meet humanity’s CO2 mitigation goals, hiding in plain sight. Significantly curtailing global wildfires will provide a huge chunk of the CO2 budget necessary to meet climate goals in the next thirty years, while we work to reduce CO2 from other sources. 

Understanding the challenge

In September 2020 SAF leaders met with the directors of CAL FIRE Aviation to identify the main challenges to current aerial firefighting operations. We learned that the biggest foundational challenge is that fires can start anytime, anywhere, and firefighting agencies are subject to human and operational limits that constrain rapid response to new fires. A lightning strike deep in the forest can become a dangerous wildfire before it is detected or reported, and grow even more before agencies can put boots on the ground or deploy aircraft to directly attack the fire.

The CAL FIRE directors further enumerated specific challenges to the present aerial attack system as:

  1. A shortage of trained pilots to fly air-tankers
  2. Lengthy startup and cycle times for large air tankers to load, launch and arrive on-scene
  3. Operational constraints that prevent crews from flying at night
  4. The high cost of air tankers and their maintenance (about $24M each)
  5. The hazards of aircrew exposure (chemical, smoke inhalation, collision) and corresponding limitation on missions
Editor’s note: To be clear, SAF has deep admiration for CAL FIRE and other firefighting agencies who have bravely and tirelessly served the public in the fight against wildfire devastation, and our goal is to augment their efforts.

Further research by SAF revealed other challenges and needs for aerial fire-fighting:

  • The need for a global early detection network that can issue prompt dispatch of firefighting assets
  • The need for aerial attack that can make precise, low-level drops of fire suppressing liquid with minimal wind scatter Large air tankers drop retardant from high up, risking wind scatter)
  • The need to avoid contamination of waterways with eco-toxic fire retardants
  • 53% of wildfires of > 10,000 acres happen outside the 10AM-6PM pilot’s flying window

AAF: An new aerial system for fighting wildfires

SAF staff devoted three years of study to developing a system to end wildfires by meeting these challenges. The result is a proposal for a new system called Autonomous Aerial Firefighting (AAF). AAF is a moonshot project to deploy aerial firefighting systems at massive scale to stop wildland fires before they become unmanageable. In brief, the project consists of:

  • Continuous monitoring of fire-prone regions using satellites and autonomous aerial systems
  • A modular fleet of autonomous, electric firefighting aircraft called eTankers
  • A network of micro airparks distributed throughout wildfire-prone areas

AAF system in operation

The mission of AAF is to effectively contain and control any nascent wildfire within the first hour after its outbreak, 24/7, in any location. To achieve this an integrated system of detection, suppression and agency cooperation is needed. Let’s examine an imagined AAF incident story:

  • 12:00 AM, Saturday night during fire season: Lightning strikes a tree in remote Mendocino County. Windy, dry weather conditions allow sparks to ignite the tree and nearby ground fuels. A forest fire has started.
  • 12:02 AM: A high-altitude long-endurance (HALE) AAF drone system detects the strike and sends an incident notification to CAL FIRE. CAL FIRE systems analyze the notification, and determine that based on available data this fire is high-risk.
  • 12:03 AM: An action order is dispatched to an AAF micro base near Philo, California, a small town 10 miles from the incident location. Within seconds a high-speed observation drone is launched, flying towards the incident at 150mph.  At the same time eight small eTankers wake up and instantly move into takeoff formations on a 300 foot runway.
  • 12:04 AM: All eTankers are airborne, flying towards the incident.
  • 12:07 AM: The observation drone is on site. There is indeed a fire, and the drone analyzes local conditions: fire size, wind conditions and tree canopy terrain. Using machine learning the AAF system creates an air drop plan, complete with 4D flight path and precision timing for eTanker drops.
  • 12:10 AM: The eTankers approach the fire and adjust their formation to match the air drop plan instructions. Their nimble, autonomous control systems allow them to fly in tight formation, and skim the treetops.
  • 12:11 AM The eTankers each drop 150 gallons of liquid on the fire to douse the flames, like an aerial bucket brigade. The observation drone makes micro-adjustments to the plan, allowing eTankers to douse at exact altitudes for maximum effectiveness. The resulting dispersion pattern has slowed the fire.
  • 12:12 AM eTankers immediately return to the micro airbase for refilling operations. The observation drone stays on site, updating the plan in realtime.
  • 12:18 AM eTankers land at the micro airbase in close formation and navigate to refilling stations where their liquid tanks and batteries are robotically swapped.
  • 12:20 AM The eTanker fleet is once again airborne.
  • 12:20 – 12:45 AM The eTankers have slowed the spread of the wildfire and continue to douse. When not dousing the eTankers loiter near the incident and pounce on flare ups as needed. 
  • 3:00 AM When CAL FIRE ground crews arrive on scene their commander coordinates local control of the observation drone and eTankers, preventing them from making drops in areas where crews are working. Once fully in control of the fire the commander sends eTankers home. The risk of a massive and dangerous wildfire has been averted.

AAF system principles

The story above depicts an amazing symphony of technologies and systems achieving a challenging goal, and may strain credulity of some readers. While advanced, we now believe such a system is achievable by integrating the best of current technology developments in aerospace, robotics, machine learning, sensing, batteries, motors and control systems integrations.

A few key principles guide the system design

  • Scale – Our studies indicate that at full capacity, AAF aircraft could arrive on-scene 4 times faster and drop 20 times more liquid than present aerial attack systems.
  • Modularity – a fleet of thousands of eTankers provides resilience and reconfigurability to meet conditions in nearly real time
  • Autonomy – Unmanned operation of observation systems, eTankers and micro airbases allow for continuous, high-cadence operations not limited by human operators who cannot operate in smoke, darkness and high winds
  • Ubiquity – Today’s existing air attack bases typically occupy more than a thousand acres owing to the very long runways required by very large airtanker (VLAT) aircraft. AAF proposes a distributed network of small 3-acre micro airbases located strategically close to susceptible areas to wildfire.  
  • Safety – Compared to VLATs, the relatively small size and payload, electric propulsion and very quiet Extremely short take-off and landing (ESTOL) operations of eTankers reduces the noise, climate impacts and overhead danger of aerial firefighting
  • Integration – AAF is proposed as an early countermeasure to wildfires, which will slow flame spread until ground crews and larger air tankers can arrive on scene to fully suppress the fire, and is not meant as a single-point solution to the problem. This approach is consistent with CAL FIRE and other agencies’ multi-modal approach to firefighting.

Guided by these principles, SAF has created a reference design for AAF to investigate such solutions, including aircraft design, robotic refilling & recharging, airbase distribution and other key details. Further, we have connected with key industry players to build a coalition of partners ready to start an integrated development and testing program for a phased AAF buildout. Details on this reference design and other operational details are available in this white paper on AAF.

An eTanker firefighting aircraft prepares to take flight

An eTanker prepares for rapid deployment

The autonomous modular system for loading fire-suppressing payload into an eTanker

Funding the AAF commitment

AAF will be costly to develop and deploy at full scale, but as covered above will mitigate billions of dollars of impending climate costs. In addition to these cost defrayals, our studies indicate that the development of AAF will yield significant second-order economic benefits during the development and operation phases. Among those benefits are:

  1. Potential use as passenger-carrying transit aircraft
  2. Potential use for last-mile cargo and logistics missions
  3. A revitalized small aerospace sector
  4. New manufacturing techniques for EVs, batteries, robotics, and composite structures
  5. Regional economic development through support of AAF airbases

These benefits are secondary to the primary mission of CO2 reduction, yet hold huge potential as an economic engine to support AAF and other climate initiatives.

Taking action

Ending wildfires would massively reduce atmospheric CO2 in the coming decades and buy us much-needed time to address the climate crisis through other mitigations. The threat of climate-related chaos and financial damages makes this opportunity too great to ignore.

As introduced above, our study indicates that an effective aerial firefighting system to end wildfires is within our collective reach, and SAF is prepared to share these analyses and reference designs in order to advance the AAF initiative.

We need your help to get this plan enacted, with a commitment to scale that would meaningfully address the challenge and opportunity. Whether you are an individual or member of the public sector, government agency or international organization, we would like to engage with you on these topics to quickly take action. 

How to get involved

  1. Spread the word by sharing this article with your network
  2. Join our mailing list to receive periodic updates on SAF and AAF work
  3. Let us know if you’re interested in collaborating on advancing AAF. We are currently seeking advocates in the public sector who can advance the AAF project within local, state and national agencies.