Author Archives: Marc Macias-Fauria

OUPF Fall 2020 Seminar Series

Do join us this Fall term with our online seminar series!!

Seminars take place every Wednesday afternoon and are announced in Oxford Talks, our website, and our mailing list.

Please find more information on the individual events in our events page or at the bottom of our Home Page.

14 October (16h BST)

04 November (16h BST)

  • Speaker: Dr Isla Myers-Smith (University of Edinburgh)
  • Title: The Greening of the Arctic – What do the data tell us?

11 November (16h BST)

  • Speakers: Dr Neven Fučkar (ECI, University of Oxford) and PhD candidate Sam Cornish (Department of Earth Sciences, University of Oxford)
  • Title: Sea ice predictions in the Coupled Model Intercomparison Project Phase 6 (CMIP 6)

18 November (18h BST)

  • Speaker: Dr Alan Friedlander (Pristine Seas, National Geographic Society, & Hawaiʿi Institute of Marine Biology, University of Hawaiʿi)
  • Title: Creating a marine protected area for the Western Antarctic Peninsula

25 November (16h BST)

02 December (16h BST)

 

 

Seminars are streamed in Zoom:

 

Warming Temperatures Are Driving Arctic Greening

As Arctic summers warm, Earth’s northern landscapes are changing. Using satellite images to track global tundra ecosystems over decades, a new collaborative study involving the University of Oxford and global institutions across the world, found the region has become greener, as warmer air and soil temperatures lead to increased plant growth.

For the expanded story, visit https://www.geog.ox.ac.uk/news/2020/20200924-warming-temps-driving-arctic-greening.html

Read the publication Summer warming explains widespread but not uniform greening in the Arctic tundra biome in Nature Communications.

Sea-ice-free Arctic makes permafrost vulnerable to thawing

 

New research, published in Nature, led by scientists at the University of Oxford’s Department of Earth Sciences, and at the Geological Survey of Israel, provides evidence from Siberian caves suggesting that summer sea ice in the Arctic Ocean plays an essential role in stabilising permafrost and its large store of carbon.

More info on this study at http://www.ox.ac.uk/news/2020-01-08-sea-ice-free-arctic-makes-permafrost-vulnerable-thawing

Read the paper – ‘Palaeoclimate evidence of vulnerable permafrost during times of low sea ice’ –  online in Nature.

New study changing our understanding of deep-ocean process key to regulating Earth’s climate

Dr Helen Johnson, Associate Professor of Physical Oceanography at the Dept. of Earth Sciences, Oxford, has co-authored a new international study that has found that the Atlantic meridional overturning circulation, a deep-ocean process that plays a key role in regulating Earth’s climate, is primarily driven by cooling waters west of Europe.

Contrary to the prevailing scientific view that most of the overturning and variability occurs in the Labrador Sea off Canada, the study shows that most of this occurs in regions between Greenland and Scotland, where warm salty waters carried northward from the tropics sink and convert into colder, fresher deep waters moving south through the Irminger and Iceland basins.

Here, overturning variability was seven times greater than in the Labrador Sea, accounting for 88% of the total variance documented across the entire North Atlantic over the 21-month study period.

Helen Johnson and Professor of Physical Oceanography David Marshall participated in the study, led by Duke University in the United States and the National Oceanography Centre in the UK.

“The overturning circulation has a major impact on how the Atlantic sector responds to climate change” said Marshall. “Recent work at Oxford has shown that the high latitude North Atlantic is the most important region for understanding how the overturning responds to anthropogenic climate change”.

“Changes in the rate of overturning affect the transfer of heat to high latitudes and can impact on Arctic sea ice” added Johnson.

“These findings, unexpected as they may be, can help scientists better predict what changes might occur to the meridional overturning circulation and what the climate impacts of those changes will be”, said project lead Susan Lozier (Duke University, United States).

The paper, published on 1 February in Science, is the first from the £25 million, five-year initial phase of the OSNAP (Overturning in the Subpolar North Atlantic Program) research project, in which scientists have deployed moored instruments and sub-surface floats across the North Atlantic to measure the ocean’s overturning circulation and shed light on the factors that cause it to vary.

Primary funding came from the US National Science Foundation’s Physical Oceanography Program and the UK Natural Environment Research Council. Additional funding came from the European Union 7th Framework Programme and Horizon 2020.

Photo: Helen Johnson

Link to publication: “A Sea Change in Our View of Overturning – First Results from the Overturning in the Subpolar North Atlantic Program
DOI:10.1126/science.aau6592

Arctic Ocean Freshwater Content and Its Decadal Memory of Sea‐Level Pressure

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Arctic freshwater content (FWC) has increased significantly over the last two decades, with potential future implications for the Atlantic meridional overturning circulation down stream. We investigate the relationship between Arctic FWC and atmospheric circulation in the control run of a coupled climate model. Multiple linear lagged regression is used to extract the response of total Arctic FWC to a hypothetical step increase in the princi pal components of sea-level pressure. The results demonstrate that the FWC adjusts on a decadal timescale, consistent with the idea that wind-driven ocean dynamics and eddies determine the response of Arctic Ocean circulation and properties to a change in surface forcing, as suggested by idealized models and theory. Convolving the response of FWC to a change in sea-level pressure with historical sea-level pressure variations reveals that the recent observed increase in Arctic FWC is related to natural variations in sea-level pressure.

View the article here: Open Publication

Reindeer deaths in the Arctic linked with retreating sea ice.

Press release on reindeer mortality in Yamal, by Dr Marc Macias-Fauria, from the University of Oxford School of Geography and the Environment. ‘Understanding the relationship between retreating sea ice and Arctic animal and plant life is essential if we are to predict how ecosystems will respond to rapid, ongoing environmental change. We are losing sea ice at an accelerating rate in the Barents and Kara Seas and our analysis suggests this is why there is more rain over the land in this region. This has implications both for the reindeer populations, as well as the last nomadic tribe in the Arctic for whom reindeer herding has been a way of life for countless generations.’

Check it out here.