Jake Slobe | February 8, 2017
The likelihood of extreme wildfires, or “megafires,” across the world is expected to increase as global temperatures continue to rise, a new study says.
The research, published in Nature Ecology & Evolution, uses satellite data to identify the 500 most extreme wildfires in recent years. Almost a third of these mega-fires caused deaths, burned down homes, or were declared a disaster by a national government.
Using climate change projections for the middle of this century, the study predicts there will be a 35% increase in the days with a high danger of fire across the world. Some regions will see even larger increases, say the researchers, including western states in the US, southeastern Australia, the Mediterranean and southern Africa.
The study uses satellite data collected by imaging instruments aboard two NASA satellites, Terra and Aqua. Using this data, the researchers identified more than 23 million wildfires globally between 2002 and 2013. While the most severe fires are often loosely dubbed “megafires”, the researchers went a step further by identifying the 500 most extreme wildfires to carry forward for their analysis.si
Of the 500, 22 were ruled out as they were caused by volcanic eruptions or industrial fires. With the remaining 478, the researchers assessed which ones could be classed as “disasters.” There are many definitions of wildfire disasters, the researchers note, many of which focus on the economic impacts – but there is no consistent global database for this. So the researchers based their definition on whether an emergency was declared or the fires caused death or loss of property. For this, they used national disaster databases, news reports and internet searches.
96% of these disastrous mega fires occurred during periods of unusually hot and/or dry weather, the researchers say.
The study projects how the Fire Weather Index (FWI) – an estimate of wildfire risk based on weather conditions and how dry the landscape is – will change the world in future. They look specifically at the changes in “high” fire danger under a climate change scenario where global CO2 emissions aren’t curbed.