To many people, the Arctic is an almost unimaginably remote area at the end of the Earth – more a land of fable and fantasy than a real part of the everyday world. Most people have very little day-to-day connection with the forests, the fields, and the people who are all part of the vast boreal ecosystem. Yet, in a very real way, the health of every person and every ecosystem on Earth is linked to the health Arctic. We are all connected to the Arctic – and that connection is carbon.
It is because of this vital connection to the Earth’s health – the carbon stored in the frozen soil and the vast forestlands of the Arctic region – that it is imperative to understand the boreal ecosystem. As a carbon sink, the boreal region helps stabilize the Earth’s climate by keeping carbon in storage, and out of the atmosphere. But a warming climate may bring increased fires to the forest, and rapid decomposition of thawing carbon-rich soil. Both burning and decomposition release carbon into the atmosphere – which, in turn, is expected to increase warming.
Driven by the desire to learn more about a vital, yet scantily studied, region, a dedicated team of scientists from NASA and Russia’s Academy of Science are embarking on a two week expedition in the remote boreal forests of northern Siberia. The international team, led by Jon Ranson, Chief of the Biospheric Sciences Branch at NASA’s Goddard Space Flight Center and Slava Kharuk of the Sukachev Forest Institute, will hop a helicopter in Tura, and then disembark on the banks of the remote Embenchime (Em- bem- chee-may) River in far northern Siberia.
They will be studying the larch forests (taiga) of the region to broaden the understanding of the Siberian larch forest in many ways, including validating measurements of forest height, structure and biomass which have already been made by the ICESat satellite’s GLAS instrument, looking at the fire history and fire-return intervals in the region, and making visual observations to collect information on any changes that may be occurring due to regional warming, including tree heights, growth patterns, types of trees which grow there, and the location of the taiga-tundra ecotone – the place where forest gives way to scrubby grassland.
Another, very important, reason for this expedition is to pave the way for use of a unique, well-tested, yet little utilized instrument package, so that it can be flown over these same forests over the next two years to collect high-resolution, detailed data on forest structure. Known as the Goddard Lidar, Hyperspectral and Thermal (G-LiHT) system, it contains imaging lidar, visible and near infrared hyperspectral and thermal capabilities. This instrument package is small enough and sturdy enough to fit aboard Russian aircraft, and has the potential to characterize the forest with more accuracy that has been available up to this time.
The Arctic Carbon Connection
The boreal ecosystem encompasses a vast region along the northern edges of North America, Europe, and Asia, including the Arctic Circle. Named after Boreas, the Greek god of the north wind, the world’s boreal forest is huge – almost 20 million square kilometers (more than 7.7 million square miles), or 29 times the state of Texas. In Russia, larch is the dominant tree species in the taiga, covering some 278 million ha, or 42% of Russian forests, and occupying about 70% of the permafrost areas in Siberia.
The roots of the taiga’s forests grow in a unique soil – one which is almost entirely made up of carbon. In much of the boreal biome, this carbon-rich soil is comprised of thick layers of peat – dead plant matter that decomposes very slowly or not at all. A meter or so below the moss-covered surface, the soil is frozen – a state the both stabilizes the carbon stores of the soil and slows the growth of forest trees.
Between the trees and the frozen soil, the Arctic region holds a vast amount of carbon, tucking it away and keeping it out of the atmosphere. In fact, Scientists estimate that while the boreal forest occupies about 21% of the Earth’s forested land surface and contains 13% of all the carbon stored in biomass (or living matter), it holds about 43% of all of the world’s carbon that is stored in soil.
Once released, carbon becomes a greenhouse gas (carbon dioxide), which contributes strongly to global warming. In a warming Arctic, peat soils begin to thaw, releasing both carbon and methane (another powerful greenhouse gas). Also, dead trees, which currently stand literally “frozen” in time, undecomposed over hundreds of years, will begin to decompose as temperatures rise. Also, as the taiga dries in warmer weather, the incidence of fires are predicted to increase. Both fire and decomposition release carbon, increasing the concentration of greenhouse gases.
Because the Arctic holds so much carbon, it is known as a carbon “sink”. As long as the Arctic stays cold, and the forests of the region continue to absorb carbon emitted by other sources (particularly human activity) our climate in our home latitudes can also remain relatively stable. Should the Arctic thaw, however, the release of both carbon and methane can heavily contribute to a warming world.
Warmth has already come to much of the Arctic. In the last 40 years, scientists have reported that the average temperatures have increased over these regions by as much as 1.25°C per decade. In northern Siberia, average temperatures have risen 1 to 3°C (3 to 5°F) over the past 30 years, whereas the worldwide average increase in that time is 0.6°C (1°F).
Back to the Future
The NASA-Sukachev scientists have been intensely interested in Siberia’s boreal ecosystem for decades. Dr. Jon Ranson and Dr. Slava Kharuk have both committed their entire careers to improving understanding of the region, and have partnered in their study since 1991. The Embenchime River Expedition will mark their 10th expedition together in the remote forests of Siberia.
In 2007 and 2008, the expeditions were similar, traveling for weeks to measure forests on the banks of the Kochechum (2007) and the Kotuykan (2008) Rivers. The Embenchime is one of the major tributaries to the Kochechum and flows one valley to the south of it, so this expedition returns to similar conditions as the team experienced in 2007.
The waters of both the Kochechum and Embenchime come primarily from summer melt of winter ice and snowfields. Even in high summer, the rivers are icy cold, and sometimes unpredictable. Heavy rains upstream can swell the rivers with surprising swiftness, causing rapidly rising waters to soak a campsite placed too close to the river. The waters can also become dangerously fast with no notice, so the scientists must sport life jackets at all time when on the river.
An expedition in Siberia is hard work, under strenuous and dangerous conditions, with hordes of mosquitoes buzzing about. Despite the adversity, these two scientists have returned to these forests, again and again, for over two decades – and plan to return as long as they are able. It’s not sheer adventure that brings them back to these beautiful but harsh conditions, again and again. They are driven by the need to learn more about the boreal ecosystem and its integral role in the health of the Earth. From these ongoing studies, these scientists hope to help the Earth, and all of her inhabitants, have a more habitable future.