Carbon dioxide poisoning dry ice1/24/2024 Since the 1970s, the Arctic has warmed at least three times faster than anywhere else on Earth, transforming its waters and ecosystems, the scientists said. And while the study focused on a particular corner of the Arctic Ocean, it can help tell a larger story of environmental change unfolding in the region. Such insights are critical because about half of the area of the Arctic Ocean is composed of coastal waters, where land meets sea in a complex embrace. “With our model, we are trying to explore the real contribution of the coastal peripheries and rivers to the Arctic carbon cycle,” said lead author Clément Bertin, a scientist at Littoral Environnement et Sociétés in France. However, the observational record is sparse along the coastal fringes of the Arctic, where the terrain, sea ice, and long polar nights can make long-term monitoring and experiments challenging. Scientists have for decades studied how carbon cycles between the open ocean and atmosphere, a process called air-sea CO2 flux. The release of CO2 into the atmosphere varied between seasons, being more pronounced in warmer months, when river discharge was high and there was less sea ice to cover and trap the gas. The researchers, from France, the U.S., and Canada, found that the river discharge was triggering such intense outgassing in the southeastern Beaufort Sea that it tipped the carbon balance, leading to a net CO2 release of 0.13 million metric tons per year – roughly equivalent to the annual emissions from 28,000 gasoline-powered cars. The scientists used the model to simulate the discharge of fresh water and the elements and compounds it carries – including carbon, nitrogen, and silica – across nearly 20 years (from 2000 to 2019). NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team The model assimilates nearly all available ocean observations collected for more than two decades by sea- and satellite-based instruments (sea level observations from the Jason-series altimeters, for example, and ocean-bottom pressure from the GRACE and GRACE Follow-On missions). To fill that void, the study team adapted a global ocean biogeochemical model called ECCO-Darwin, which was developed at NASA’s Jet Propulsion Laboratory in Southern California and the Massachusetts Institute of Technology in Cambridge. But there has been great uncertainty due to a lack of data from the remote region. Scientists have thought of the southeastern Beaufort Sea as a weak-to-moderate CO2 sink, meaning it absorbs more of the greenhouse gas than it releases. Some of the carbon is eventually released, or outgassed, into the atmosphere by natural processes. That material drains into the Beaufort Sea as a soup of dissolved carbon and sediment. Along the way, the river acts as a conveyor belt for mineral nutrients as well as organic and inorganic matter. In this marshy corner of Canada’s Northwest Territories, the continent’s second largest river system ends a thousand-mile journey that begins near Alberta. Like many parts of the Arctic, the Mackenzie River and its delta have faced significantly warmer temperatures in recent years across all seasons, leading to more melting and thawing of waterways and landscapes. The study, published earlier this year, explores how scientists are using state-of-the-art computer modeling to study rivers such as the Mackenzie, which flows into a region of the Arctic Ocean called the Beaufort Sea. But recent findings show that thawing permafrost and carbon-rich runoff from Canada’s Mackenzie River trigger part of the Arctic Ocean to release more carbon dioxide (CO2) than it absorbs. It’s been estimated that the cold waters of the Arctic absorb as much as 180 million metric tons of carbon per year – more than three times what New York City emits annually – making it one of Earth’s critical carbon sinks. When it comes to influencing climate change, the world’s smallest ocean punches above its weight. Runoff from one of North America’s largest rivers is driving intense carbon dioxide emissions in the Arctic Ocean. NASA Earth Observatory image by Jesse Allen using Landsat data from USGS
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