A new NASA study shows how lightning is driving forest fires and pushing it north. NASA confirms a likely link to climate change.
The worlds largest biome is named after Boreal the Greek goddess of the North Wind. The boreal forest is nearly a continuous belt of coniferous trees circling across North America, Europe and Asia. The trees grow on areas that were formerly glaciated, and in areas of patchy permafrost on all three continents. The region has 30 percent of the Earth’s forests and they store about 30 percent of the carbon found on the Earth’s surface.
The conditions are very harsh so there is not much diversity of life. Plant life is limited because most species can’t survive the extreme cold that lasts 6 months or more. Plant species, such as lichens and mosses will grow there as well as coniferous trees such as pine, spruce and fir which form the vast majority of the plant life that exists. The animals that do call the Boreal home tend to be predators like lynx, wolverines, bobcats and minks. They feed on the herbivores in the area such as rabbits, squirrels and voles. Larger mammals such as deer, elk, and moose can be found only in regions of the forest where some deciduous trees can grow. The boreal forests play a vital role in Earth's climate system by sequestering carbon dioxide.
Science Daily reports on the many challenges this biome is facing due to human induced climate change.
At the same time, boreal forests are one of the ecosystems most affected by climate change, with temperatures in the arctic and boreal domains recently warming at rates as high as 0.5°C per decade, and potential future warming of 6 to 11°C over vast northern regions by 2100, according to the IPCC's most pessimistic scenario, RCP 8.5.
Studies have shown that climate zones in boreal forests are moving northwards ten times faster than the trees' ability to migrate. Warmer and drier conditions and enhanced variability of climate may have already contributed to increased extent of wildfires, and the spread of outbreaks of dangerous insects. Thawing permafrost poses threats to the hydrological system at the continental scale, as well as the potential of releasing huge amounts of CO2 and methane. Locally, increasing non-forestry industrial development, accompanied by air pollution, soil and water contamination, might reinforce the negative impacts of climate change. Overall, these factors mean that huge areas of boreal forest will be at high risk of impoverishment or change to grassland or shrubland.
"These forests evolved under cold conditions, and we do not know enough about the impacts of warming on their resilience and buffering capacity," says Shvidenko.
The NASA funded study found that lightening storms are the main culprit of recent massive fires that have burned in Alaska and northern Canada’s boreal forests. The study found that these electrical storms are “likely to move farther north with climate warming, potentially altering northern landscapes”.
NASA reports that lightning-ignited fires broke records in the Canadian Northwest Territories in 2014 and in Alaska in 2015. Researchers found “increases of between two and five percent a year in the number of lightning-ignited fires since 1975.
We found that it is not just a matter of more burning with higher temperatures. The reality is more complex: higher temperatures also spur more thunderstorms. Lightning from these thunderstorms is what has been igniting many more fires in these recent extreme events," Veraverbeke said.
Study co-author Brendan Rogers at Woods Hole Research Center in Falmouth, Massachusetts, said these trends are likely to continue. "We expect an increasing number of thunderstorms, and hence fires, across the high latitudes in the coming decades as a result of climate change." This is confirmed in the study by different climate model outputs.
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The researchers found that the fires are creeping farther north, near the transition from boreal forests to Arctic tundra. "In these high-latitude ecosystems, permafrost soils store large amounts of carbon that become vulnerable after fires pass through," said co-author James Randerson of the University of California, Irvine. "Exposed mineral soils after tundra fires also provide favorable seedbeds for trees migrating north under a warmer climate."
"Taken together, we discovered a complex feedback loop between climate, lightning, fires, carbon and forests that may quickly alter northern landscapes," Veraverbeke concluded. "A better understanding of these relationships is critical to better predict future influences from climate on fires, and from fires on climate."