A new study led by Lance Lesack, a Simon Fraser University geographer and Faculty of Environment professor, has discovered unexpected climate-driven changes in the mighty Mackenzie River’s ice breakup. This discovery may help resolve the complex puzzle underlying why Arctic ice is disappearing more rapidly than expected.
Lesack is the lead author on Local spring warming drives earlier river-ice breakup in a large Arctic delta. Published recently in Geophysical Research Letters, the study has co-authors at Wilfrid Laurier University, the University of Alberta and Memorial University.
Its goal was to understand how warming global temperatures and the intensifying Arctic hydrological cycle associated with them may be driving increasing water discharges and more rapid ice breakup in the Arctic’s great rivers.
But the researchers stumbled upon an unexpected phenomenon while trying to figure out why the Mackenzie River’s annual ice breakup has been shortening even though its water discharge isn’t increasing, as in Russian rivers.
Just slightly warmer springs with unexpected snowfall declines — rather than warmer winters or increasing river discharge, as previously suspected — can drive earlier-than-expected ice breakup in great Arctic rivers.
The Mackenzie exemplifies this unexpected phenomenon. The researchers discovered this by accessing records dating back to 1958 of the river’s water levels, snow depths, air temperatures and times of ice breakup.
This finding is significant, as Arctic snow and ice systems are important climate-system components that affect the Earth’s ability to reflect solar radiation.
“Our surprising finding was that spring temperatures, the period when river-ice melt occurs, had warmed by only 3.2 degrees Celsius. Yet this small change was responsible for more than 80 per cent of the variation in the earlier ice breakups, whereas winter temperatures had warmed by 5.3 degrees but explained little of this variation,” says Lesack.
“This is a strong response in ice breakup for a relatively modest degree of warming, but further investigation showed that by winter’s end snow depths had also declined by one third over this period. The lesser snow depths mean less solar energy is needed to drive ice breakup.”
Lesack says this is the first field-based study to uncover an important effect of reduced winter snowfall and warmer springs in the Arctic — earlier-than-expected, climate-change-related ice breakup.
“The polar regions have a disproportionate effect on planetary reflectivity because so much of these regions consist of ice and snow,” says Lesack. “Most of the planetary sea ice is in the Arctic and the Arctic landmass is also seasonally covered by extensive snow. If such ice and snow change significantly, this will affect the global climate system and would be something to worry about.”
Lesack hopes this study’s findings motivate Canadian government agencies to reconsider their moves towards reducing or eliminating ground-based monitoring programs that measure important environmental variables.
There are few long-term, ground-based snow depth records from the Arctic. This study’s findings were based on such records at Inuvik dating back to 1958. They significantly pre-dated remote sensing records that extend back only to 1980. Without this longer view into the past, this study’s co-authors would still be in the dark about the more rapid than expected Arctic melt and planetary heat-up happening.
Quotes by Lance Lesack
Simon Fraser University is consistently ranked among Canada's top comprehensive universities and is one of the top 50 universities in the world under 50 years old. With campuses in Vancouver, Burnaby and Surrey, B.C., SFU engages actively with the community in its research and teaching, delivers almost 150 programs to more than 30,000 students, and has more than 125,000 alumni in 130 countries.
Carol Thorbes | EurekAlert!
Underground fungi detected from space
04.05.2016 | Smithsonian Tropical Research Institute
How much does groundwater contribute to sea level rise?
03.05.2016 | International Institute for Applied Systems Analysis (IIASA)
Using an ultra fast-scanning atomic force microscope, a team of researchers from the University of Basel has filmed “living” nuclear pore complexes at work for the first time. Nuclear pores are molecular machines that control the traffic entering or exiting the cell nucleus. In their article published in Nature Nanotechnology, the researchers explain how the passage of unwanted molecules is prevented by rapidly moving molecular “tentacles” inside the pore.
Using high-speed AFM, Roderick Lim, Argovia Professor at the Biozentrum and the Swiss Nanoscience Institute of the University of Basel, has not only directly...
If a person pushes a broken-down car alone, there is a certain effect. If another person helps, the result is the sum of their efforts. If two micro-particles are pushing another microparticle, however, the resulting effect may not necessarily be the sum their efforts. A recent study published in Nature Communications, measured this odd effect that scientists call “many body.”
In the microscopic world, where the modern miniaturized machines at the new frontiers of technology operate, as long as we are in the presence of two...
Researchers from the Max Planck Institute Stuttgart have developed self-propelled tiny ‘microbots’ that can remove lead or organic pollution from contaminated water.
Working with colleagues in Barcelona and Singapore, Samuel Sánchez’s group used graphene oxide to make their microscale motors, which are able to adsorb lead...
Neutron scattering and computational modeling have revealed unique and unexpected behavior of water molecules under extreme confinement that is unmatched by any known gas, liquid or solid states.
In a paper published in Physical Review Letters, researchers at the Department of Energy's Oak Ridge National Laboratory describe a new tunneling state of...
Honeycomb structures as the basic building block for industrial applications presented using holo pyramid
Researchers of the Alfred Wegener Institute (AWI) will introduce their latest developments in the field of bionic lightweight design at Hannover Messe from 25...
27.04.2016 | Event News
15.04.2016 | Event News
12.04.2016 | Event News
04.05.2016 | Earth Sciences
04.05.2016 | Health and Medicine
03.05.2016 | Physics and Astronomy