Record heat is burning the Arctic and melting Greenland’s ice | Science News for Students

Record heat is burning the Arctic and melting Greenland’s ice

Wildfires are pumping vast amounts of carbon dioxide into the air, which could make the problem worse
Sep 10, 2019 — 6:45 am EST
a satellite image of wildfires

 Wildfires near the Mackenzie River in Canada’s Northwest Territories. A European Space Agency satellite, called the Copernicus Sentinel-2, snapped this image on July 27.

Pierre Markuse/Flickr (CC BY 2.0)

Wildfires raged across the Arctic this summer. Record-high temperatures and strong winds fueled those fires. And those fires are occurring in greater numbers than ever recorded.

In Siberia alone, hundreds of wildfires spanned about 3 million hectares (300 million acres) of land. Satellites captured images of those fires on July 28. Across Alaska, as many as 400 wildfires were burning as of mid-July. The Arctic’s heat is also melting Greenland’s ice at an alarming rate.

The size and intensity of the June 2019 wildfires were greater than any seen in the past 16 years. That’s how long the European Union’s Copernicus Atmosphere Monitoring Service, or CAMS, has been tracking global wildfire data. This July’s numbers “have been of similar proportions,” says Mark Parrington. He’s a senior scientist at CAMS in Reading, England. “I’ve been surprised at the duration of the fires in the Arctic Circle, in particular,” he says.

Wildfires most often develop in the Arctic in July and August. They’re typically sparked by lightning. But this year, unusually hot and dry conditions in the Northern Hemisphere in June made the problem worse. That brought the fire season to an earlier-than-usual start. The World Meteorological Organization (WMO) reported this on July 12.

High temperatures and little Arctic rainfall almost certainly played a role in the July wildfires as well, Parrington says.

Heat and fire

In Alaska, temperatures reached as high as 32.2° Celsius (90° Fahrenheit) on July 6. That broke the state’s previous heat record.

June temperatures also were higher than usual in parts of Siberia. That’s in northern Russia. Average temperatures there were almost 10 degrees Celsius higher than the averages from 1981 to 2010. Also in June, more than 100 intense wildfires raged within the Arctic Circle.

Greenland certainly has been sweltering. The island lost nearly 200 billion tons of ice in July. That’s according to the Danish Meteorological Institute. On July 31, 56.5 percent of Greenland’s ice sheet was showing signs of melting, reports Ruth Mottram. She’s a glaciologist (Glay-see-OL-oh-gizt). She studies glaciers at the Danish Meteorological Institute in Copenhagen.

a satellite image showing Greenland melting
On August 1, the Copernicus Sentinel-3 satellite took this image of western Greenland. An active wildfire burns to the left of the island’s ice sheet. Meanwhile, abundant melt ponds (seen here as blue spots) collect atop the ice. This is another effect of record high temperature.
Pierre Markuse/Flickr (CC BY 2.0)

August 1 images from the Copernicus satellite show multiple melt ponds on Greenland. They also show burn scars on the island from a recent fire and smoke from an active fire.

Arctic blazes are not only scorching vast areas of Earth. Those flames also are releasing large amounts of carbon dioxide (CO2). June’s fires alone released more than 50 metric megatons of CO2, the WMO said. That’s more than the amount released, or emitted, by all June fires combined from 2010 to 2018.

Total CO₂ emitted from July’s Arctic wildfires is estimated at about 79 megatons, Parrington says. That’s double the emissions from July 2004. Until now, that had been the previous record-setting month. The year 2004 also set an annual record. Total Arctic wildfire CO₂ emissions hit about 110 megatons that year. This year has already smashed that record.

People and machines

Emissions of CO₂ and other greenhouse gases are responsible for modern global warming. Most increases in greenhouse gases are caused by human activities. These gases have already warmed the planet by 1 degree C (1.8 degrees F) above levels seen before the Industrial Revolution.

Temperatures in the Arctic are increasing twice as fast as the global average. That rapid warming has added to the growth and persistence of wildfires there.


Carbon dioxide emissions from wildfires in the Arctic in July, 2003–2019

a graph showing Carbon dioxide emissions from wildfires in the Arctic in July, 2003–2019
Wildfires emitted about 79 metric megatons of carbon dioxide in the Arctic Circle in July 2019. That smashed the previous record set in July 2004.
CAMS

Arctic wildfires are expected to become more common as the planet warms. There’s geologic evidence to support that. Layers of black charcoal have been found in sediments in the Canadian Arctic. That suggest wildfires frequently raged through the region during the Pliocene Epoch. But that was some 3 million years ago.

Back then, global atmospheric CO₂ levels were between 350 and 450 parts per million. Today’s measurements are similar. In June, CO₂ levels averaged 413.92 ppm. That’s according to data collected at the Mauna Loa Observatory in Hawaii.

Meanwhile, the frequent winter warm spells, insect outbreaks and wildfires are also causing problems for Arctic plants. Many have lost their resistance to freezing. This has caused them to dry out and die. Large parts of the Arctic have turned brown. That, in turn, has upped the region’s risk of wildfires.

Normally, the area’s icy peat-filled lands are soggy enough to be fire-resistant. But those lands are thawing and drying out. Once set ablaze, carbon-rich peat can burn for months. This releases large amounts of CO₂ back into the atmosphere. And that fuels even more warming.

Power Words

(more about Power Words)

annual     Adjective for something that happens every year.

Arctic     A region that falls within the Arctic Circle. The edge of that circle is defined as the northernmost point at which the sun is visible on the northern winter solstice and the southernmost point at which the midnight sun can be seen on the northern summer solstice. The high Arctic is that most northerly third of this region. It’s a region dominated by snow cover much of the year.

atmosphere     The envelope of gases surrounding Earth or another planet.

average     (in science) A term for the arithmetic mean, which is the sum of a group of numbers that is then divided by the size of the group.

carbon     The chemical element having the atomic number 6. It is the physical basis of all life on Earth. Carbon exists freely as graphite and diamond. It is an important part of coal, limestone and petroleum, and is capable of self-bonding, chemically, to form an enormous number of chemically, biologically and commercially important molecules.

carbon dioxide (or CO2)     A colorless, odorless gas produced by all animals when the oxygen they inhale reacts with the carbon-rich foods that they’ve eaten. Carbon dioxide also is released when organic matter burns (including fossil fuels like oil or gas). Carbon dioxide acts as a greenhouse gas, trapping heat in Earth’s atmosphere. Plants convert carbon dioxide into oxygen during photosynthesis, the process they use to make their own food.

develop     To emerge or come into being, either naturally or through human intervention, such as by manufacturing.

epoch     (in geology) A span of time in the geologic past that was shorter than a period (which is itself, part of some era ) and marked when some dramatic changes occurred.

European Union     The confederation of 28 European countries that have agreed to work peacefully together. Residents of EU can move freely between its member countries and sell goods to them. Most members have also adopted the same currency, known as the Euro.

fuel     Any material that will release energy during a controlled chemical or nuclear reaction.

geologic     An adjective that refers to things that are related to Earth’s physical structure and substance, its history and the processes that act on it. People who work in this field are known as geologists.

glacier     A slow-moving river of ice hundreds or thousands of meters deep. Glaciers are found in mountain valleys and also form parts of ice sheets.

global warming     The gradual increase in the overall temperature of Earth’s atmosphere due to the greenhouse effect. This effect is caused by increased levels of carbon dioxide, chlorofluorocarbons and other gases in the air, many of them released by human activity.

greenhouse gases     Gases that contribute to the greenhouse effect by absorbing heat. Carbon dioxide and methane are two examples of such gases.

Greenland     The world’s largest island, Greenland sits between the Arctic Ocean and North Atlantic. Although it is technically part of North America (sitting just east of Northern Canada), Greenland has been linked more politically to Europe. Ice covers roughly 80 percent of Greenland. Indeed, the Greenland ice sheet is the world’s largest. If its frozen water were to melt, it could raise sea levels around the world by 6 meters (about 20 feet).

ice sheet     A broad blanket of ice, often kilometers deep. Ice sheets currently cover most of Antarctica. An ice sheet also blankets most of Greenland. During the last glaciation, ice sheets also covered much of North America and Europe.

Industrial Revolution     A period of time around 1750 that was marked by new manufacturing processes and a switch from wood to coal and other fossil fuels as a main source of energy.

lightning     A flash of light triggered by the discharge of electricity that occurs between clouds or between a cloud and something on Earth’s surface. The electrical current can cause a flash heating of the air, which can create a sharp crack of thunder.

observatory     (in astronomy) The building or structure (such as a satellite) that houses one or more telescopes.

outbreak     The sudden emergence of disease in a population of people or animals. The term may also be applied to the sudden emergence of devastating natural phenomena, such as earthquakes or tornadoes.

peat     Largely decomposed plant material that develops in the absence of oxygen within a water-saturated site, such as a bog. When dried out, peat can be burned as a low-grade fuel.

proportion     The amount of a certain component of a mixture relative to other components. For example, if a bag contains 2 apples and 3 oranges, the proportion of apples to oranges in the bag is 2 to 3.

risk     The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. (For instance: Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.)

satellite     A moon orbiting a planet or a vehicle or other manufactured object that orbits some celestial body in space.

sediment     Material (such as stones and sand) deposited by water, wind or glaciers.

Siberia     A region in northern Asia, almost all of which falls within Russia. This land takes its name from the language of the Tatar people, where Siber means sleeping land. This region is vast. It has become famous for its long, harsh winters, where temperatures can fall to −68° Celsius (−90° Fahrenheit).

World Meteorological Organization     Created in 1950, this is a special agency of the United Nations. More than 190 nations and territories belong to WMO, which serves as the official “voice” on the status of the planet’s atmosphere and how it is behaving. WMO is based in Geneva, Switzerland.

Citation

Website: Danish Meteorological Institute. Greenland daily surface conditions.

Report: World Meteorological Organization. Unprecedented wildfires in the Arctic. July 12, 2019. 

Report: Copernicus Atmosphere Monitoring Service. CAMS monitors unprecedented wildfires in the Arctic. July 11, 2019.