Tipping points in the Ecosystem

Antje Boetius Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung

Global Warming Accelerated

Observed change of temperature 1970 – 2017 [oC] Arctic is warming 2-3 times faster than the Northern hemisphere Indikator des Wandels : Rückgang des Meereises

www.meereisportal.de Arctic change and the perspective of an “eye witness”

1993 2012

Sea ice extent in September 1993 and 2012 (National Snow and Ice Data Center) The melting Arctic sea ice - 2012

Expedition IceArc 2012 Stefan Hendricks, AWI Change in export flux to the seafloor

100 km off North Pole 4400 m water depth, Boetius et al. Science, 2013 Arctic uncertainties of projections

Range of projected warming until 2100 IPCC climate models for RCP8.5 scenario ] C 20100 o - 2090 2015 [ 2015 - 2005 change

to Arctic relative Temperature

Antarctic Latitude Arctic

Many processes in the Understanding of key climate Arctic processes in the Arctic is limited only roughly represented by lack of observations! in Climate Models Arctic uncertainties of climate projections

Pitahn et al. 2014

https://www.nature.com/articles/ngeo2071 Loss of Arctic sea ice – depends on human paths

• loss of 3 ± 0.3 m2 of September sea-ice area per metric ton of CO2 emission

• no Arctic sea-ice in September for an additional 1000 Gt of CO2 emissions (<30 yrs) Notz & Stroeve Science 2017 What is a tipping point ?

A shift of an ecosystem to a new state, with significant changes to biodiversity, foodwebs and the services to people it underpins, at a regional or global scale.

Indicators: • The change becomes self-perpetuating • There is a threshold beyond which an abrupt shift of ecological states occurs • The changes are long-lasting and hard to reverse The Changing Arctic Cryosphere (IPCC SROCC)

Permafrost: +0.29°C ± 0.12°C per decade

Arctic Snow: -13.4 ± 5.4% per decade (-2.5 million km2)

Greenland ice mass -278 ± 11 Gt yr–1

Goddard Multimedia

Sea ice -12.8 ± 2.3% per decade Mass loss of – and

April 1996 April 2018

Mass loss of the Kronebreen- 1996-2018 ~2km Open water Massive Sea ice Permafrost melt and coastal erosion

M. Rex M. Rex

Alaska Village Permafrost melt (Sibiria) Charles Tarnocai Electric Cooperative Coastal erosion (Alaska)

„Thawing soils and plant detritus transport massive amounts of carbon to the sea" ‹Nr.›

Photo: AWI / C. Seidler • AWIPEV • Arctic research station, staffed year-round • Dedicated: 1991 as Koldewey Station in Ny-Ålesund, Spitsbergen; in 2003 merged with the French Polar Institute Paul Emile Victor (IPEV) to form the AWIPEV Temperature record of Svalbard. Black curve: long-term record • 3-person station can support max. 24 researchers at Svalbard Airport (Norwegian Meteorological Institute). • Primary research areas: Impacts of on Surface air temperature (white dots) and soil temperature at 59 fjord, glacier and tundra habitats cm depth (grey dots) recorded at the AWIPEV research base • Long-term observatories: Atmosphere and water (source: Maturilli, Boike). Warming Stripes for Svalbard (source: Ed Hawkins CC BY 4.0). ‹Nr.›

Photo: AWI Samoylov Station Yearly mean, min, max temperature at depth of the permafrost • Permafrost research station (staffed year-round) of the borehole since Russian Academy of Sciences, on Samoylov Island in the installation (source: Siberian Lena Delta Boike). • Dedicated: 2013 as successor to the Samoylov Summer Station

1910 1930 1950 1970 1990 2010 • 8-person station team can support max. 25 visiting researchers Warming Stripes for Sakha Republic (source: Ed Hawkins CC BY 4.0). • Primary research areas: Experimental long-term permafrost research Exploring he polar night ! Indikator des Wandels : Rückgang des Meereises

www.meereisportal.de Shift in seasonal patterns likely to affect biotic interactions

Seasonality in the sea ice habitat

Chl a

Keck & Wassmann 1993 Sea ice algae and phytoplankton are light-limited: sunlight for primary production19 only from May to September Hard to reverse: threats to a productive, unique ecosystem Hard to reverse: threats to a productive, unique ecosystem

Haakon Hop, Norwegian Polar Institute FRAM | FRontiers in Arctic Marine Monitoring: Autonomous observations under the ice FRAM Pollution Observatory: Microplastics

Atmosphere Arctic snow Ø = 1.800 N L-1 Bergmann et al. (eingereicht) Sea ice Ø = 4.500 N L-1 Sea surface Ø = 0.51 N L-1

Water column Ø = 0.19 N L-1 Tekman et al.

Deep sea sediments Ø = 2.300 N L-1 Arctic change – understanding thresholds in biological systems

2 4 Managing threats to a unique region

Sea ice, permafrost Arctic Circle & Observers glacier loss Moratorium on fisheries in Warming the central Arctic

Acidification International Code Operations in Polar Waters Pollution and plastic littering Strong multidisciplinary science & infrastructure Non-sustainable Aquaculture New steps towards reducing CO2 emissions and new alliances MOSAiC: exploring the polar night

https://follow.mosaic-expedition.org/

84N and 135E