Wildfires

• Climate warming in the western United States is causing changes to the wildfire regime in mixed‐conifer forests.

• Rising temperatures, longer fire seasons, increased drought, as well as fire suppression and changes in land use, have led to greater and more severe wildfire activity, all contributing to altered forest composition over the past century.

• Widespread severe wildfires under climate change lead to increased forest homogeneity in dry mixed‐conifer forests.

• Projected climate change generated a 20% increase in the number of extreme fire years (years with at least 40,000 ha burned).

• Human-caused climate change made southeastern Australia’s devastating wildfires during 2019–2020 at least 30 percent more likely to occur, researchers report in a new study published online March 4.

• A prolonged heat wave that baked the country in 2019-2020 was the primary factor raising the fire risk.

• Such an intense heat wave in the region is about 10 times more likely now than it was in 1900, the study found.

• During the last decades, climate and land use changes led to an increased prevalence of megafires in Mediterranean-type climate regions (MCRs).

• The Mediterranean-type climate regions (MCRs) are distributed over five continents: Africa, Australia, Europe, North America, and South America.

• More recently, human alterations of landscapes and climate have led to strong changes in fire regimes and their socio-ecological impacts in all five MCRs.

Although no one wants to be put in this situation, it may be inevitable for lots of people, depending on where they live. The effects of a wildfire can linger on long after it is burned out, so here are some precautions one can take after a wildfire.

The CDC recommends to reduce your smoke exposure. Smoke can stay in the air for several days after the fire ends, and there are a few ways to reduce the exposure, both inside and outside.

Ways to reduce exposure inside:

• Use high-efficiency filters to capture particles from the smoke.

• Seek shelter from somewhere else if you lack resources or it is too hot to stay inside with windows and doors closed.

• Pick the room with the fewest exposures to outside air (with fewer doors/windows/fireplaces) and stay in that room while using an air filter.

Ways to reduce exposure outside:

• Know your air quality. Air quality and smoke measures can change frequently throughout a day, so check with airnow.gov to check the quality.

• Reduce smoke getting into your car by keeping windows and vents closed, and running air conditioning in recirculate mode.

• If you must be outdoors in smoky conditions, an N95 respirator can help protect you more than a bandana or dust mask.

• Know how you will get air quality information and where you will possibly need to evacuate.

• Wildfires cause immense damage and we hear about most of it on the news; acres lost, homes destroyed, and wildlife perishing in the fires. But, I have not heard about the lasting health effects of wildfires.

• Studies have shown that there is a direct connection between decreased lung function in people without asthma and wildfire smoke exposure.

• Individuals exposed to wildfire smoke also are at risk for respiratory infections.

• There is also evidence that birth weights can be affected when the pregnant mother is exposed to wildfire smoke. Pregnant women exposed to large amounts of wildfire smoke have higher rates of giving birth to low-weight babies.

-Since August of 2020, record-breaking wildfires have burned 2.7 million hectares along the West Coast of the United States

• More than 30 people have died and tens of thousands are homeless as a result

-As climate change gets worse, the risk of wildfires will continue to increase in most areas of the world

• Fires will increase excess mortality and morbidity from burns, wildfire smoke, and mental health effects

-High greenhouse-gas emissions and forest lost from the fires are likely to speed up climate change further which can lead to a reinforcing feedback loop

Climate Change and Wildfires

-A wildfire needs three conditions to start:

• These are known as the fire triangle:

  • • Fuel, Oxygen, and an ignition source

    • Climate change can increase the chances that all of these will be present

-Rainfall has become more concentrated in the winter months, which makes other seasons especially summer, hotter and drier

• This causes increased evaporation of the moisture in soil which can fuel wildfires

-Climate change is predicted to increase the differences in temperature between land and sea

• This can result in differences in air pressure among land and sea and causes higher wind power in tropical and southern subtropical areas

• Strong winds provide more oxygen for wildfires and encourage their spread to the point where firefighters can't stop them

-Increases in the frequency and intensity of heat waves under climate change provide more ignition sources for fires

• There has been an increase in lightning strikes in North America and Siberia as the result of climate change

-Since we have a warming climate, the wildfire season is starting much earlier and ending much later

• Now there is a bigger window for which wildfires can occur and a smaller window for prescribed burning which is the burning of available vegetation during cooler seasons in effort to reduce the risk of wildfires

-Setting of fires to convert tropical forest to open lands that can be used for agriculture, cattle ranches, and lands for real-estate contribute to climate change and release large amounts of greenhouse gases and air pollutants

-The risk and severity of wildfires in forests are expected to increase in the future

-From the years 1997 to 2016, carbon dioxide emissions form wildfires equaled about 22% of the carbon emissions from burning fossil fuels

• Losing tropical forests due to wildfires decreases the Earth’s ability to absorb CO2 and cool the climate

-Wildfires that occur in the Artic could melt the permafrost and lead to the release of previously frozen carbon and methane, which is stronger than CO2

Health Risks Associated with Wildfires

Direct Health risks From Wildfire Events

-Firefighters and people living near wildfires can experience burns, injuries, mental health effects, and death due to exposure to flames or radiant heat

• Firefighters are at high risk for heat-related illnesses such as dehydration-induced heat cramps to life threatening heat strokes

• Residents are at increased risk for mental illness, such as PTSD, depression, and insomnia

• A 20 year follow up study concluded that exposure to wildfires as a child was connected with the increased change of mental illness in adulthood

  • • Wildfires have also been associated with a decrease in academic performance in children

Health Risks From Wildfire Smoke

-Heavy smoke can cause eye irritation and corneal abrasions and can reduce ones visibility which can increase the risk of traffic accidents

-Even from 1000 km away, the smoke can increase ambient air pollution and increase risk of illness and death

Air Pollutants from Wildfire Smoke

-Primary air pollutants from wildfire smoke:

• Particulate matter

• Carbon monoxide

• Nitrogen oxides (nitrogen dioxide and nitric oxide)

• Volatile organic compounds (VOCs)

-A photochemical reaction between (VOCs) and nitrogen oxides under sunlight create a secondary pollutant, ground-level ozone

-Peat Fires: may extend up to 20 m underground and result in very high levels of air pollution such as CO2 and many potentially toxic compounds, including formaldehyde and hydrogen cyanide

-Major pollutants of public health during wildfires are:

• Carbon monoxide, ozone, and particulate matter

• CO stays within the relative area of the fire while ozone and particulate matter spread much further

Short-Term Health Effects of Wildfire Smoke

-In comparison to combustion of fossil fuels, wildfire particulate matter has smaller particle size and has more oxidative and proinflammatory components that lead to stronger toxic effects

-Exposure to particulate matter from wildfires increases your risk for respiratory illnesses such as Chronic Obstructive Pulmonary Disease and Asthma

Long-Term Health Effects of Wildfire Smoke

-Those exposed have lower results for lung capacity, self-reported general health, and physical functioning than those not exposed to wildfire smoke

Vulnerable Populations Affected by Wildfire Smoke

-People 65 years of age or older

-Preexisting cardiac or respiratory conditions and pregnant women

-Children are more susceptible to harmful effects from wildfire smoke because their respiratory and immune systems are less mature

Protecting Health against Wildfires

-Have emergency supplies gathered before wildfire season

• These should include: food, water, medication, goggles, and face masks

-Have a community evacuation plan

-During and after wildfires, residents in affected areas should avoid drinking water that could be contaminated by ash, fire retardant, dead animals, or damaged water pipes

• Have bottled water readily available

Mitigating Wildfire Risks by Limiting Global Temperature Increase

-In a scenario of high greenhouse gas emissions, wildfires will increase in frequency by over 74% by end of this century

• If steps are taken to limit the global mean temperature, then 60-80% of the increase in wildfire exposure could be avoided

-Reducing carbon emissions is hard and expensive but its benefits outweigh the costs in many areas

Conclusion

-Wildfires are linked to increased morbidity and mortality

-Societal action is needed

-If we do not try and limit the global temperature increase, wildfires and climate change are likely to form a reinforcing feedback loop that will make wildfires and their health consequences increasingly severe

The climate and humans have both had a profound effect on wildfire activity in the world. The amount of global burning can fluctuate dramatically over time, and differ drastically throughout hundreds of years. NASA has been conducting research as to why such trends exist in order to predict what may happen in the future. Many variables govern wildfire activities, the main ones being global temperature and moisture, but human activity has made calculations more complicated.

NASA researchers have finally conducted models which display the history of wildfires throughout the entire globe, where previously the predictions were only set to certain parts of the world. The research concludes that after a population boom and the Industrial Revolution, humans have been a more prevalent cause of wildfire trends since the 18^th century.

Conducting the model:

NASA researchers Olga Pechony and Drew Shindell made a fire model which combines previous fire/climate models which takes different variables such as greenhouse gas emissions, population, temperature, moisture, and others into consideration. Next, they can change the year and past results (going back to 844) will show the fire trends and provide expectations of future fire trends.

What to expect in the future:

When projecting the model forward, Pechony and Shindell modeled three different greenhouse-gas emissions scenarios, “One that curtailed greenhouse-gas emissions significantly, one that assumes they continued unabated, and on in the middle. All three produced rapidly rising temperatures, regional drying, and increases in fire abundance.”

The scientists conclude that changes region to region will vary dramatically, and globally there will be a wildfire increases of around 5%. Also, unexpectedly, they think that areas with more greenhouse-gas emissions will have less wildfires because of more capability of aggressive and abundant firefighting.

Global average fire abundance has decreased since 1900 due to advances in firefighting, but by 2050, global warming will reverse that decline.

Predicted locations of large increases in fire activity:

• India

• Australia

• Central Asia and Siberia

• Southern Europe

• Southern Africa

Predicted locations of decreases in fire activity:

• Northern Europe

• South America

• Equatorial Africa

(This is due to increased precipitation).