ZOMBIE FIRES

Introduction

• ‘Zombie fires’ are becoming more frequent in the Arctic region.
• A ‘zombie fire’ is a fire left from a previous growing season.
• Because Arctic soils are often densely packed with flammable organic matter, such as peat, above ground fires that burn themselves out can leave the ground smoldering.
• When winter comes, snow can actually insulate the smoking mat from the cold air above as it consumes peat and pockets of flammable methane gas.
• These conditions can sometimes allow a zombie fire to keep burning until temperatures warm and the snow melts away.
• When the weather warms further, the fire can reignite.

Recent Findings

• Fires in the Arctic are spreading to areas which were formerly fire-resistant.
• The tundra — north of the Arctic Circle — is drying up and vegetation there like moss, grass, dwarf shrubs, etc are starting to catch fire.
• In 2019 and 2020, burning occurred well above the Arctic Circle, a region not normally known to support large wildfires.
• Nearly all of this year’s fires inside the Arctic Circle occurred on continuous permafrost, with over half of these burning on ancient carbon-rich peat soils.
• As per the World Meteorological Organization (WMO), June 2019 was Earth’s warmest June on record. Due to large part to this heat surge, wildfires are now running rampant in Siberia, Greenland, Alaska and Canada, producing plumes of smoke visible from space.

 

Why is the Arctic warming up so fast?

• The Arctic’s extreme warming, known as Arctic amplification or polar amplification, is due to three factors:

 Albedo

• One, the region’s reflectivity, or albedo—how much light it bounces back into space—is changing as the world warms?
• Since ice is white, it reflects the sun’s energy.
• Sea ice is melting rapidly in the Arctic, the darker ocean surface is absorbing more of the sun's heat due to the removal of white surface.
• That’s warming the region’s waters, and potentially raising temperatures on land as well.

 Changing Currents

• The second factor: changing currents. Ocean currents normally bring in warmer water from the Pacific, and colder water exits out of the Arctic into the Atlantic.
• But those currents are changing because more melting ice is injecting the Arctic Ocean with freshwater, which is less dense than saltwater, and therefore floats above it.
• The missing ice also exposes the surface waters to more wind, speeding up the Beaufort Gyre in the Arctic, which traps the water it would normally expel into the Atlantic.
• This acceleration mixes up colder freshwater at the surface and warmer saltwater below, raising surface temperatures and further melting ice.
  • The Beaufort Gyre is one of the two major ocean currents in the Arctic Ocean, it is roughly located north of the Alaskan and Canadian coast.
  • An ocean gyre is a large system of circular ocean currents formed by global wind patterns and forces created by Earth's rotation.
  • The movement of the world's major ocean gyres helps drive the “ocean conveyor belt.” The ocean conveyor belt circulates ocean water around the entire planet.

Influence of Ocean Current on Weather

• Ocean Currents drive the powerful polar jet stream, which moves hot and cold air masses around the Northern Hemisphere.
• This is a product of the temperature differences between the Arctic and the tropics.
• But as the Arctic warms, the jet stream now undulates wildly north and south.
• This has been injecting the Arctic with warm air in the summer.

Jet Streams The polar jet stream is found high up in the atmosphere where the Ferrell and Polar cells come together. A jet stream is a fast-flowing river of air at the boundary between the troposphere and the stratosphere. Jet streams form where there is a large temperature difference between two air masses.

Impact of wildfires

• The fires are releasing copious volumes of previously stored carbon dioxide and methane - carbon stocks that have in some cases been held in the ground for thousands of years.
• Thus the fires and record temperatures have the potential of turning the carbon sink into a carbon source and increasing global warming.
• A lot of the particulate matter from these fires will eventually come to settle on ice surfaces further north, darkening them and thus accelerating melting.
• Greenhouse gases emitted will further exacerbate greenhouse warming, leading to more fires.
• Arctic infernos released 50 megatons of carbon dioxide—the equivalent of Sweden’s total annual emissions—into the atmosphere in June alone.
• Vicious cycle: Climate change-induced heat waves trigger Arctic wildfires, which in turn contribute to climate change by releasing carbon dioxide and pollutants into the atmosphere.
• Temperatures in the Arctic have been increasing at a much faster rate than the global average.
• It's all part of a process of Arctic amplification.

Tackling Arctic Wildfires

• There is a need to understand the nature of fires in the Arctic which are evolving and changing rapidly.
• There is also an urgent need of global cooperation, investment and action in monitoring fires.
• It important to learn from the indigenous peoples of the Arctic about how fire was traditional used.
• New permafrost- and peat-sensitive approaches to wild land fire fighting are needed to save the Arctic.