Embedded Files
Wild fires: Global Phenomenon
Wild fires: Global Phenomenon
The risk of devastating wildfires around the world will surge in the coming decades as climate change further.
In a moderate scenario for global warming, the likelihood of extreme, catastrophic fires could increase by up to a third by 2050 and up to 52 percent by 2100, the report estimates. If emissions are not curbed and the planet heats up more, wildfire risks could rise by up to 57 percent by the end of the century.
The scientific assessment is the first by the organization’s environmental authority to evaluate wildfire risks worldwide. It was inspired by a string of deadly blazes around the globe in recent years, burning the American West, vast stretches of Australia, and even the Arctic.
But hot weather and weak rainfall can also decrease the amount of vegetation that is available to feed fires. In other places, the decreased humidity can make vegetation more flammable, helping fires spread more easily.
Wildfires:
Wildfires:
Weather Conditions
Weather Conditions
Fire danger in a wildland setting varies with weather conditions: drought, heat, and wind participate in drying out the timber or other fuel, making it easier to ignite. Once a fire is burning, drought, heat, and wind all increase its intensity. Topography also affects wildfire, which spreads quickly uphill and slowly downhill. Dried grass, leaves, and light branches are considered flash fuels; they ignite readily, and fire spreads quickly in them, often generating enough heat to ignite heavier fuels such as tree stumps, heavy limbs, and the organic matter of the forest floor. Such fuels, ordinarily slow to kindle, are difficult to extinguish. Green fuels—growing vegetation—are not considered flammable, but an intense fire can dry out leaves and needles quickly enough to allow ready ignition. Green fuels sometimes carry a special danger: evergreens, such as pine, cedar, fir, and spruce, contain flammable oils that burst into flames when heated sufficiently by the searing drafts of a forest fire.
Wild fires: Climatic Impact
Wild fires: Climatic Impact
The many people affected by devastating bushfires in southeast Australia in December 2019 and January 2020 may have greater concerns than whether these events were primarily a manifestation of climate change. However, future policy and practice that seek to minimize both the scale and impacts of future fire events do need to consider this question. Extreme events like bushfires and floods are rarely related in a simple way to general trends in climate, so any argument for more action on greenhouse gas (GHG) emissions is likely to prove an over‐simplification, in other words, the generalization. Also, it has long been known that the climate of southeast Australia is characterized by distinct but irregular oscillations, between periods of a few years dominated by drought that may lead to fires (Kiem & Franks, 2004), and a few years with high rainfall and floods (Kiem et al., 2003).
These oscillations seem to be related to ocean-atmosphere interactions leading to fluctuations that include the El Niño‐Southern Oscillation (or ENSO) in the Pacific Ocean (a three to seven-year fluctuation) and the Indian Ocean Dipole (IOD; three to five years). Such sources of variability are part of the prevailing climatic regime of southeast Australia, rather than being a climatic change, and are not directly related to GHG emissions.
Global warming arising from GHG emissions may, however, be intensifying the amplitudes and changing the phases of these quasi‐periodic phenomena (Abram et al., 2020; King et al., 2017), and altering their frequency – as Cai et al. (2009) have noted with respect to increased occurrence of positive IOD conditions (warmer water off East Africa). But the signals of these cycles can be identified in the Australian Late Quaternary record long before anthropogenic warming (Beck et al., 2017).
And while the “fire‐adapted” nature of the native vegetation has generated controversy about how far this reflects periodic climate‐related drought or periodic burning by pre-colonial Indigenous peoples (Benson & Redpath, 1997), the very adaptation itself has clearly had a much longer history than that of anthropogenic global warming. A decade ago, on what is known as Black Saturday (7th February 2009), severe and extensive bushfire activity occurred in the state of Victoria, resulting in the destruction of around 2,850 homes and 173 fatalities. The death rate makes this seem an even greater disaster than the 2019–2020 event, for which equivalent figures are approximately 5,900 and 34; the lower ratio of deaths to property losses in 2019–2020 may reflect improvements in disaster response and community resilience after 2009.
Following Black Saturday, Crompton et al. (2010) analyzed 100 years of data to assess whether the 2009 bushfires had indeed been particularly severe. This led to the conclusion that Black Saturday was (then) the second-worst bushfire event in terms of normalized fatalities and the fourth-worst in terms of normalized building damage. The normalization process suppressed any evidence of a trend of rising relative damage and death. The authors accordingly reported that “… it is not possible to detect a greenhouse‐gas climate‐change signal… it is dwarfed by the magnitude of the societal change and the large year‐to‐year variation in impacts” (p. 308). A complex chain of causation leads from the climate (with its structured temporal variability) and anthropogenic climate change, through their impacts on drought, its impact on vegetation and the fuel supply for fires, the ignition sources, and the development of fires, to their impacts on property and people (Richards, 2020).
Damages of Wildfires: Impact
Damages of Wildfires: Impact
Environmental
Environmental
Destruction of wildlife habitats
Endangered species
Climate change due to increased carbon dioxide emissions
ECONOMIC
ECONOMIC
Loss of income
from timber, livestock, and forestry products
Loss of environmental functions of forests
Decrease in tourists
Health
Health
Burns and injuries
Eye, nose, throat, and lung irritation
Decreased lung function, including coughing and wheezing
Pulmonary inflammation, bronchitis, exacerbation of asthma, and other lung diseases
Exacerbation of cardiovascular diseases, such as heart failure
Release significant amounts of mercury into the air, which can lead to impairment of speech, hearing, and walking, muscle weakness, and vision problems for people of all ages.
Page updated
Report abuse