. 24/7 Space News .
ICE WORLD
Mastodons migrated vast distances in response to climate change
by Brooks Hays
Washington DC (UPI) Sep 01, 2020

Climate change fuels sharp increase in glacier lakes
Paris (AFP) Sept 1, 2020 - The volume of lakes formed as glaciers worldwide melt due to climate change has jumped by 50 percent in 30 years, according to a new study based on satellite data.

"We have known that not all meltwater is making it into the oceans immediately," lead author Dan Shugar, a geomorphologist and associate professor at the University of Calgary, said in a statement.

"But until now there were no data to estimate how much was being stored in lakes or groundwater."

The findings, published Monday in Nature Climate Change, will help scientists and governments identify potential hazards to communities downstream of these often unstable lakes, he said.

They will also improve the accuracy of sea level rise estimates through better understanding of how -- and how quickly -- water shed by glaciers makes it to the sea.

Between 1994 and 2017, the world's glaciers, especially in high-mountain regions, shed about 6.5 trillion tonnes in mass, according to earlier research.

"In the past 100 years, 35 percent of global sea-level rises came from glacier melting," Anders Levermann, climate professor at the Potsdam Institute for Climate Change Impact, told AFP.

The other main sources of sea level rise are ice sheets and the expansion of ocean water as it warms.

- Glacial lake outbursts -

Earth's average surface temperature has risen one degree Celsius since preindustrial times, but high-mountain regions around the world have warmed at twice that pace, accelerating glacier melt.

Unlike normal lakes, glacier lakes are unstable because they are often dammed by ice or sediment composed of loose rock and debris.

When accumulating water bursts through these accidental barriers, massive flooding can occur downstream.

Known as glacial lake outbursts, this kind of flooding has been responsible for thousands of deaths in the last century, as well as the destruction of villages, infrastructure and livestock, according to the study, published in Nature Climate Change.

The most recent recorded incident was a glacial lake outburst that washed through the Hunza Valley in Pakistan in May.

In January, the UN Development Programme estimated that more than 3,000 glacial lakes have formed in the Hindu Kush-Himalayan region, with 33 posing an imminent threat that could impact as many as seven million people.

The new study, based on 250,000 scenes from NASA's Landsat satellite missions, estimates current glacial lake volume at more than 150 cubic kilometres (37 cubic miles), equivalent to one-third the volume of Lake Erie in the United States or twice the volume of Lake Geneva.

A decade ago, it would have not been possible to process and analyse that volume of data, said Shugar.

Before their disappearance at the end of the Pleistocene, North American mastodons trekked hundreds of miles across the continent, altering their range in response to dramatic climatic shifts, according to research published Tuesday in Nature Communications.

In a largest-of-its-kind survey of mastodon mitochondrial genomes, using DNA collected from 33 individual animals, researchers were able to retrace the movements of ancient mastodon populations.

"We used one genetic marker known as the full mitochondrial genome," Hendrik Poinar, evolutionary geneticist and director of the Ancient DNA Center at McMaster University in Canada, told UPI in an email. "This is a maternally inherited marker that does not recombine and allows us to trace migration history and female population size through time."

"We compared the mitochondrial genomes from all mastodons to say something about where they fall in relation to each other," Poinar said. "When combined with their geographical location you can make sense of migrational direction."

The genomic data showed mastodons from farther north featured lower levels of genetic diversity, suggesting smaller subsets of southern populations migrated north.

By comparing differences in the number of genetic mutations between individual mastodons and geographically distinct groups of mastodons, researchers were able to better understand the relationships between different population subsets. They also were able to estimate when different branches of the family tree split off and migrated elsewhere.

When researchers compared the timing of mastodon migrations with paleoclimate evidence, they were able to confirm that groups of mastodons headed north as temperature rose and glaciers receded.

"The interglacial occupation of mastodons has been proposed for a few years now, but I think we show the strongest evidence of it," lead study author Emil Karpinski, graduate student at the Ancient DNA Center, told UPI.

Scientists have previously suggested North American mastodons were hunted to extinction by people of the Clovis culture, a prehistoric Paleoamerican culture that spread across the continent some 13,000 years ago. But the latest research suggests climate change likely played a role in the mastodon's disappearance.

"[The findings] certainly suggest that the mastodons migrated huge distances over the course of generations, tracking environments that favored their ecology, but ultimately that they were susceptible to changing climate, perhaps priming them for human predation," Poinar said.

The researchers say their findings have implications for modern conservation science. Today, a variety of animal species, including elk and bears, are expanding their ranges northward as a result of anthropogenic greening.

"If these northern populations show the same pattern as mastodons, they might also be very similar genetically and the loss of populations in the southern ranges may have detrimental effects for the genetic health of the species," Karpinski said.

Earth's ice sheets tracking worst-case climate scenarios
Paris (AFP) Sept 1, 2020 - The Greenland and Antarctic ice sheets, which hold enough frozen water to lift oceans 65 metres, are tracking the UN's worst-case scenarios for sea level rise, researchers have said, highlighting flaws in current climate change models.

Mass loss caused by melt-water and crumbling ice from 2007 to 2017 aligned with the most extreme forecasts from the Intergovernmental Panel for Climate Change (IPCC), which see the two ice sheets adding up to 40 centimetres (nearly 16 inches) to global oceans by 2100, they reported on Monday in Nature Climate Change.

Such an increase would have a devastating impact worldwide, increasing the destructive power of storm surges and exposing coastal regions home to hundreds of millions of people to repeated and severe flooding.

That is nearly three times more than mid-range projections from the IPCC's last major Assessment Report in 2014, which predicted a 70 centimetre rise in sea level from all sources, including mountain glaciers and the expansion of ocean water as it warms.

Despite this clear mismatch between the observed reality of accelerating ice sheet disintegration and the models tracking those trends, a special IPCC report last year on the planet's frozen regions maintained the same end-of-century projections for Greenland, and allowed for only a small increase from Antarctica under the highest greenhouse gas emissions scenario.

"We need to come up with a new worst-case scenario for the ice sheets because they are already melting at a rate in line with our current one," lead author Thomas Slater, a researcher at the Centre for Polar Observation and Modelling at the University of Leeds, told AFP.

"Sea level projections are critical in helping governments plan climate policy, mitigation and adaptation strategies.

"If we underestimate future sea level rise, then these measures may be inadequate and leave coastal communities vulnerable."

Ice sheet losses at the upper end of the IPCC forecasts would by itself expose some 50 million people to annual coastal flooding worldwide by mid-century, according to research published last year.

- Balance upended -

Several factors explain why the climate models underlying UN projections for sea level might have given short shrift to ice sheets, according to the new analysis.

Ice sheet models do well in describing the long-term impact of gradual global warming, which has seen temperatures at the poles rise far more quickly than for the planet as a whole.

But they have failed to account for short-term fluctuations in weather patterns that are, themselves, deeply influenced by climate change.

"For Greenland, much of the ice loss is now being driven by surface melt events during hot summers -- processes not captured in the AR5 simulations," said Slater, referring to the 2014 IPCC report, the fifth since 1992.

"We need to understand these better to improve our sea level rise predictions."

Until the turn of the 21st century, the West Antarctic and Greenland ice sheets generally accumulated as much mass as they shed. Runoff, in other words, was compensated by fresh snowfall.

But over the last two decades, the gathering pace of global warming has upended this balance.

Last year, Greenland lost a record 532 billion tonnes of ice -- the equivalent of six Olympic pools of cold, fresh water flowing into the Atlantic every second. This run-off accounted for 40 percent of sea level rise in 2019.

"We have now had record breaking ice loss twice in less than 10 years," said Twila Moon, a research scientist at the University of Colorado, noting that the previous melts on this scale were 150 and 600 years ago.

"If everyone's alarm bells were not already ringing, they must be now."

A new generation of climate models that better reflects how ice sheets, the oceans and the atmosphere interact will underpin the IPCC's next major report, which will be completed next year, said Slater.

In another study published earlier this month in The Cryosphere, a journal of the European Geosciences Union, Slater and colleagues calculated that Earth's ice masses -- including mountain glaciers, the Arctic ice cap, and both ice sheets -- lost nearly 28 trillion tonnes of mass between 1994 and 2017.

Less than half of that amount contributed to sea level rise. The Arctic ice cap, for example, forms in the ocean, and thus does not increase sea level when it melts.

The rate of ice loss, they found, has increased nearly 60 percent of that time period.


Related Links
Beyond the Ice Age


Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly


paypal only
SpaceDaily Contributor
$5 Billed Once


credit card or paypal


ICE WORLD
Global survey using NASA data shows dramatic growth of glacial lakes
Washington DC (SPX) Sep 01, 2020
In the largest-ever study of glacial lakes, researchers using 30 years of NASA satellite data have found that the volume of these lakes worldwide has increased by about 50% since 1990 as glaciers melt and retreat due to climate change. The findings, published in the journal Nature Climate Change, will aid researchers assessing the potential hazards to communities downstream of these often unstable lakes and help improve the accuracy of sea level rise estimates by advancing our understanding of how ... read more

Comment using your Disqus, Facebook, Google or Twitter login.



Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

ICE WORLD
ISS crew moved to Russian segment for 3 days to search for air leak

NASA perseveres through pandemic, looks ahead in 2020, 2021

Moonstruck 'aroma sculptor' builds scent from space

A QandA on the Demo-2 mission

ICE WORLD
Skyrora's Skylark Micro rocket launches from Iceland

Under pressure, nontoxic salt-based propellant performs well

Sierra Nevada aims to complete Dream Chaser space plane in March

SpaceX sets rocket booster reuse record in satellite launch

ICE WORLD
Follow Perseverance in real time on its way to Mars

Sustained planetwide storms may have filled lakes, rivers on ancient mars

Deep learning will help future Mars rovers go farther, faster, and do more science

NASA establishes Board to initially review Mars sample return plans

ICE WORLD
China's Mars probe over 8m km away from Earth

China seeks payload ideas for mission to moon, asteroid

China marching to Mars for humanity's better shared future

From the Moon to Mars: China's long march in space

ICE WORLD
Satellite constellations could hinder astronomical research, scientists warn

ESA astronauts are flat out training

Ban on import of communication satellites opens up opportunity says ISRO chief

SES picks SpaceX to launch four additional O3b mPower satellites

ICE WORLD
NOAA selects Orbit Logic for enterprise scheduling

New ground station brings laser communications closer to reality

Nellis AFB, Nev., opens pilots' virtual training center

'FreeFortnite' tournament taunts Apple amid legal battle

ICE WORLD
Pristine space rock offers NASA scientists peek at evolution of life's building blocks

Rogue planets could outnumber the stars

The most sensitive instrument in the search for life in space comes from Bern

Microbes living on air a global phenomenon

ICE WORLD
Technology ready to explore subsurface oceans on Ganymede

Large shift on Europa was last event to fracture its surface

The Sun May Have Started Its Life with a Binary Companion

Ganymede covered by giant crater









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.