Climate researchers Nicholas Balascio and Francois Lapointe dealing with an ice auger to drill in the 3.5m thick ice at South Sawtooth Lake, Ellesmere Island, Nunavut Territory, Canada. An ice auger extension is required since the ice is so thick. Coring lake sediments can just be done after this tiresome work, Lapointe notes. Credit: Mark B. Abbott
University of Massachusetts Amherst, Canadian research study utilizes ancient lake sediments to extend environment record.
Taking benefit of special residential or commercial properties of sediments from the bottom of Sawtooth Lake in the Canadian High Arctic, environment researchers have actually extended the record of Atlantic sea-surface temperature level from about 100 to 2,900 years, and it reveals that the hottest period over this duration has actually been the past 10 years.
A group led by Francois Lapointe and Raymond Bradley in the Climate System Research Center of the University of Massachusetts Amherst and Pierre Francus at University of Québec-INRS examined “perfectly preserved” yearly layers of sediment that built up in the lake on northern Ellesmere Island, Nunavut, which include titanium left over from centuries of rock weathering. By determining the titanium concentration in the various layers, researchers can approximate the relative temperature level and air pressure with time.
The recently extended record programs that the coldest temperature levels were discovered in between about 1400-1600 A.D., and the hottest period took place throughout simply the previous years, the authors report. Francus includes, “Our unique data set constitutes the first reconstruction of Atlantic sea surface temperatures spanning the last 3,000 years and this will allow climatologists to better understand the mechanisms behind long-term changes in the behavior of the Atlantic Ocean.”
A Twin Otter research study aircraft on frozen Sawtooth Lake in Canada’a High Arctic. Credit: Mark B. Abbott.
When temperature levels are cool over the North Atlantic, a fairly low air pressure pattern is discovered over much of the Canadian High Arctic and Greenland. This is related to slower snow melt because area and greater titanium levels in the sediments. The reverse holds true when the ocean is warmer – air pressure is greater, snow melt is quick and the concentration of titanium declines.
Lapointe states, “Using these strong links, it was possible to reconstruct how Atlantic sea surface temperatures have varied over the past 2,900 years, making it the longest record that is currently available.” Details were released on October 12, 2020, in Proceedings of the National Academy of Sciences.
The scientists report that their recently rebuilded record is substantially associated with numerous other independent sediment records from the Atlantic Ocean varying from north of Iceland to offshore Venezuela, validating its dependability as a proxy for the long-lasting irregularity of ocean temperature levels throughout a broad swath of the Atlantic. The record is likewise comparable to European temperature levels over the previous 2,000 years, they mention.
Fluctuations in sea surface area temperature levels, called the Atlantic Multidecadal Oscillation (AMO), are likewise connected to other significant weather turmoils such as dry spells in North America and the intensity of typhoons. However, since measurements of sea surface area temperature levels just return a century or two, the precise length and irregularity of the AMO cycle has actually been improperly comprehended.
Climate warming in the Arctic is now two times or 3 times faster than the remainder of the world since of greenhouse gas emissions from burning nonrenewable fuel sources, warming can be enhanced or moistened by natural environment irregularity, such as modifications in the surface area temperature level of the North Atlantic, which appear to differ over cycles of about 60-80 years.
Lapointe, who has actually performed comprehensive fieldwork in the Canadian Arctic over the previous years, keeps in mind that “It has actually prevailed in current summer seasons for climatic high-pressure systems – clear-sky conditions – to dominate the area. Maximum temperature levels frequently reached 20 degrees Celsius, 68 degrees Fahrenheit, for lots of succeeding days or perhaps weeks, as in 2019. This has actually had permanent effect on snow cover, glaciers and ice caps, and permafrost.”
Bradley includes that “The surface waters of the Atlantic have been consistently warm since about 1995. We don’t know if conditions will shift towards a cooler phase any time soon, which would give some relief for the accelerated Arctic warming. But if the Atlantic warming continues, atmospheric conditions favoring more severe melting of Canadian Arctic ice caps and the Greenland ice sheet can be expected in the coming decades.”
In 2019, Greenland Ice Sheet lost more than 500 billion lots of mass, a record, and this was related to extraordinary, relentless high pressure climatic conditions.”
Lapointe notes, “Conditions like this are currently not properly captured by global climate models, underestimating the potential impacts of future warming in Arctic regions.”
Reference: “Annually resolved Atlantic sea surface temperature variability over the past 2,900 y” by Francois Lapointe, Raymond S. Bradley, Pierre Francus, Nicholas L. Balascio, Mark B. Abbott, Joseph S. Stoner, Guillaume St-Onge, Arnaud De Coninck, and Thibault Labarre, 12 October 2020, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2014166117
