Investigating the Changing Arctic
The Arctic is at the epicenter of climate change: warming is greatest in the Arctic, arctic ecosystems are particularly sensitive to warming, and changes in the Arctic can strongly impact the global climate system. Perhaps more than any other large region on Earth, the Arctic functions as a “system” with land, ocean, and atmospheric components of the system tightly coupled. The Arctic contains Earth’s largest forest (called the taiga or boreal forest), several of Earth’s largest rivers, and vast amounts of ancient organic carbon that is now vulnerable to release as carbon dioxide or methane – both greenhouse gases – as permafrost thaws. For these reasons and others, scientists at the Woods Hole Research Center are leading several international efforts to understand both the impacts of climate change on the Arctic as well as the feedbacks from the Arctic to the global climate system.
Tundra north of the Arctic Circle (66 degrees N) in Alaska. Photo by Scott Goetz.
Using River Chemistry to Assess Arctic Watersheds
Just as a physician can analyze blood chemistry to assess the health of a patient, a scientist can use river water chemistry to investigate the “health” of a watershed. Scientists at the Woods Hole Research Center are analyzing the discharge and chemistry of large rivers from around the world, striving to understand how disturbances such as climate change or deforestation are impacting the rivers and altering the transport of materials from land to the ocean (see Global Rivers Project pages). For almost a decade, WHRC scientists have worked with an international team of scientists on the six largest rivers in the Arctic (see map below), collecting water samples multiple times per year from each of the rivers and then transporting the samples to Woods Hole for chemical analysis. Now known as the Arctic Great Rivers Observatory and funded by the National Science Foundation, this project has made fundamental advances in the understanding of land-ocean interactions in the Arctic and has “set the baseline” against which to judge future changes in the Arctic. Illustrating the tight and important coupling between different components of the Arctic System, WHRC’s work on the biogeochemistry of large arctic rivers is leading to fundamental advances in the understanding of both land and ocean in the Arctic.
Watersheds of the six largest rivers in the Arctic, all of which are part of the Arctic Great Rivers Observatory project. Together these rivers account for the majority of river water inputs to the Arctic Ocean, and the discharge and chemistry provides important clues about changes occurring in their massive watersheds. For perspective, the Ob’, Yenisey, and Lena rivers are all comparable in size and annual discharge to North America’s largest river, the Mississippi.
Senior Scientist Max Holmes sampling the Lena River.
Satellite and Field-Based Approaches to Studying Terrestrial Productivity and Fire
The Arctic environment has experienced dramatic changes over the past few decades as the region is subjected to greater temperature increases and more frequent and intense drought conditions. The 2010 fires in Russia, preceded by equally intense fires in North America in 2004, 2005 and 2009, signal a regime shift that could persist for decades. In addition to fire, boreal forests have experienced widespread productivity declines documented not only with satellite observations but also by field observations, including tree rings and CO2 exchange measurements. Tundra regions, by contrast, are responding positively to the warmer conditions. Productivity in these treeless regions has increased, as observed with satellite imagery and field measurements of shrub growth. These differing changes may result partly because tundra areas are not yet moisture limited – even though rare tundra fires have expanded in recent years, including one in 2007 on the North Slope of Alaska that burned some 256,000 acres.
Notably, then, the circumpolar boreal forest is an integral part of the global ecosystem and has important influences on the global cycling of energy, carbon and water. Over the past 30 years, global boreal forests have experienced a significant amount of warming and drying which, if trends continue as predicted, are likely to induce feedbacks that may further influence global climate.
One goal of the Woods Hole Research Center’s work in this region is to quantify the magnitude and variability of carbon exchange, assess the mechanisms by which fire disturbance influences these processes, and characterize how changes in these ecosystems respond to and are influencing climate. By synthesizing results from direct field measurements, satellite remote sensing and ecosystem modeling, WHRC scientists study the processes driving changes in the boreal forest in order to inform assessments and predictions of how those changes will be expressed under a future climate regime.
Using time series analyses of a 22-year record of satellite observations across the northern circumpolar high latitudes, scientists at the Woods Hole Research Center are assessing trends in vegetation photosynthetic activity. The results indicate that tundra areas consistently and predominantly show greening trends while forested areas show browning in many areas, indicating that the boreal forest biome might be responding to climate change in previously unexpected ways. Overall, tundra areas show marked greening over the entire growing season. These patterns were consistent with relatively simple climate response seen in related work in North America, where areas responded to summer maximum temperatures while the response of forest vegetation was more complex. Boreal forests patterns indicate significant greening in May and June, with gains offset by substantive browning in July and August.
Using the Allure of the Arctic to Educate and Engage Public Audiences
In addition to contributing rigorous scientific research, arctic initiatives at the Woods Hole Research Center also encompass unique educational outreach programs.
Began in 2008, the Polaris Project trains future leaders in arctic research and education, and informs the public about the impacts of climate change, essential goals given the rapid and profound transformations underway in the Arctic in response to global warming. The Polaris Project includes an annual 4-week field course in the Russian Arctic for scientists and undergraduate students from the United States, Russia, and other countries. The participants are based near Cherskii, along the Kolyma River. While there, the focus of the students’ and scientists’ work is the transport and transformations of carbon and nutrients as they move with water from terrestrial uplands to the Arctic Ocean. The Polaris Project also includes several new arctic-focused undergraduate courses taught by project co-primary investigators (PIs) at their home institutions, the opportunity for those co-PIs to initiate research programs in the Siberian Arctic, and a wide range of outreach activities.
The Woods Hole Research Center’s arctic education initiatives also include an exhibition of drawings and paintings created by schoolchildren in Zhigansk, Siberia, a small community along the banks of the Lena River. There, students have become key partners in a scientific research initiative exploring the impacts of climate change on the Arctic. The program was begun in 2002, when a 13-year-old girl named Anya, the daughter of a boat captain, just happened to be along for a research expedition along the Lena that included Max Holmes, an earth system scientist with the Woods Hole Research Center. Dr. Holmes noticed her interest in the scientific sampling work, and communicating through a little English, a little Russian, and a lot of hand signals, she quickly mastered the basic sampling protocols. Anya’s participation quickly grew to include fellow students and teachers at her school in Zhigansk, and in other communities throughout the Arctic. This initiative, which was funded by the National Science Foundation, has not only advanced scientific understanding of a part of the world already experiencing climate change, but is also creating the next generation of scientists and scientifically-literate citizens.
“Holiday of the Reindeer” by Senya Koryakin, a piece in the WHRC Arctic Art collection.
Artwork from the collection has been shown at the American Museum of Natural History (New York City), the American Association for the Advancement of Science (Washington DC), the United Nations (New York City), the Vermont State Capital, the Begich-Boggs Visitors Center at Portage Glacier in Alaska, and a variety of other venues including internationally in Moscow, St. Petersburg, and Yakutsk. An online exhibition of the collection is in development and will be available on the WHRC website in early 2011.
Photographs, including thumbnail, unless otherwise credited, © Chris Linder.