Nav: Home

Early start of 20th century arctic sea ice decline

August 30, 2019

Boulder, Colo., USA: Arctic sea-ice has decreased rapidly during the last decades in concert with substantial global surface warming. Both have happened much faster than predicted by climate models, and observed Arctic warming is much stronger than the global average. Projections suggest that Arctic summer sea-ice may virtually disappear within the course of the next fifty or even thirty years.

Although Arctic-wide warming during the 20th century is well documented, little is known about the response of sea-ice to abrupt warming and it is unclear when the sea-ice decline started. Data coverage in this region is highly restricted, with observation-based satellite data only available since the 1970s, too short to accurately calibrate climate models.

Limited observational records therefore hamper the assessment of long-term changes in sea-ice, leading to large uncertainties in predictions of its future evolution under global warming. In the absence of instrumental data, natural archives of environmental changes, so-called proxies can be used to extend climate data further back in time.

In this study published in Geology, Steffen Hetzinger and colleagues present the first annually resolved 200-year record of past sea-ice variability from High Arctic Svalbard (79.9°N) using a newly developed in situ proxy from long-lived encrusting coralline algae. Annual growth and Mg/Ca ratios in this photosynthesizing benthic marine plant are strongly dependent on light availability on the shallow seafloor, recording the duration of seasonal sea-ice cover.

This proxy opens up a new possibility to study past sea-ice variability, and unlike previously available reconstructions from mainly land-based archives, it provides an annually resolved direct in situ proxy from the surface ocean.

Due to the limited availability of instrumental data, current research largely focuses on sea-ice decline since the late 20th century. The results of this study provide evidence for an earlier start of Arctic sea-ice decline at the beginning of the 20th century, not captured by shorter observational records and land-based reconstructions.

The algae also show that lowest sea-ice values within the past 200 years occurred from the 1980s to the early 2000s. These results may help reduce the large uncertainties that exist among ocean model simulations, providing a new approach for the detection and verification of long-term Arctic sea-ice changes.
-end-
FEATURED ARTICLE

Early start of 20th century Arctic sea ice decline recorded in Svalbard coralline algae

Steffen Hetzinger et al., steffen.hetzinger@uni-hamburg.de. URL: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/573355/early-start-of-20th-century-arctic-sea-ice-decline

GEOLOGY articles are online at http://geology.geoscienceworld.org/content/early/recent. Representatives of the media may obtain complimentary articles by contacting Kea Giles at the e-mail address above. Please discuss articles of interest with the authors before publishing stories on their work, and please make reference to GEOLOGY in articles published. Non-media requests for articles may be directed to GSA Sales and Service, gsaservice@geosociety.org.

https://www.geosociety.org

Geological Society of America

Related Climate Models Articles:

Atmospheric scientists study fires to resolve ice question in climate models
Black carbon from fires is an important short-term climate driver because it can affect the formation and composition of clouds.
New soil models may ease atmospheric CO2, climate change
To remove carbon dioxide from the Earth's atmosphere in an effort to slow climate change, scientists must get their hands dirty and peek underground.
Patterns in permafrost soils could help climate change models
A team of scientists spent the past four summers measuring permafrost soils across a 5,000 square-mile swath of Alaska's North Slope.
Latest climate models show more intense droughts to come
An analysis of new climate model projections by Australian researchers from the ARC Centre of Excellence for Climate Extremes shows southwestern Australia and parts of southern Australia will see longer and more intense droughts due to a lack of rainfall caused by climate change.
Some of the latest climate models provide unrealistically high projections of future warming
A new study from University of Michigan climate researchers concludes that some of the latest-generation climate models may be overly sensitive to carbon dioxide increases and therefore project future warming that is unrealistically high.
A Europe covered in grasslands or forests: innovation and research on climate models
An experiment to better understand how atmospheric variables respond to land use changes.
How tiny water droplets form can have a big impact on climate models
Droplets and bubbles are formed nearly everywhere, from boiling our morning coffee, to complex industrial processes and even volcanic eruptions.
Individual climate models may not provide the complete picture
Equilibrium climate sensitivity -- how sensitive the Earth's climate is to changes in atmospheric carbon dioxide -- may be underestimated in individual climate models, according to a team of climate scientists.
Deep neural networks speed up weather and climate models
A team of environmental and computation scientists at the US Department of Energy's (DOE) Argonne National Laboratory are collaborating to use deep neural networks, a type of machine learning, to replace the parameterizations of certain physical schemes in the Weather Research and Forecasting Model, an extremely comprehensive model that simulates the evolution of many aspects of the physical world around us.
Climate models and geology reveal new insights into the East Asian monsoon
A team of scientists, led by the University of Bristol, have used climate models and geological records to better understand changes in the East Asian monsoon over long geologic time scales.
More Climate Models News and Climate Models Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Debbie Millman: Designing Our Lives
From prehistoric cave art to today's social media feeds, to design is to be human. This hour, designer Debbie Millman guides us through a world made and remade–and helps us design our own paths.
Now Playing: Science for the People

#574 State of the Heart
This week we focus on heart disease, heart failure, what blood pressure is and why it's bad when it's high. Host Rachelle Saunders talks with physician, clinical researcher, and writer Haider Warraich about his book "State of the Heart: Exploring the History, Science, and Future of Cardiac Disease" and the ails of our hearts.
Now Playing: Radiolab

Insomnia Line
Coronasomnia is a not-so-surprising side-effect of the global pandemic. More and more of us are having trouble falling asleep. We wanted to find a way to get inside that nighttime world, to see why people are awake and what they are thinking about. So what'd Radiolab decide to do?  Open up the phone lines and talk to you. We created an insomnia hotline and on this week's experimental episode, we stayed up all night, taking hundreds of calls, spilling secrets, and at long last, watching the sunrise peek through.   This episode was produced by Lulu Miller with Rachael Cusick, Tracie Hunte, Tobin Low, Sarah Qari, Molly Webster, Pat Walters, Shima Oliaee, and Jonny Moens. Want more Radiolab in your life? Sign up for our newsletter! We share our latest favorites: articles, tv shows, funny Youtube videos, chocolate chip cookie recipes, and more. Support Radiolab by becoming a member today at Radiolab.org/donate.