Predicting impacts of climate change in Greenland: Substituting space for time Prepared by: Mikael K. Sejr, Dorte Krause-Jensen and Paul E. Renaud A contribution to the EU project: Arctic Tipping Points 2 Substituting space for time – Greenland Substituting space for time – Greenland 3 4 Substituting space for time – Greenland Substituting space for time – Greenland 5 The Arctic is warming twice as fast as the global average. Sea ice is retreating and the Greenland ice cap is melting. Greenlandic society and Inuit culture have always relied on the ocean and its resources, but now the marine ecosystem is changing. 6 Substituting space for time – Greenland Fishing and hunting is still important for most people in Greenland and the changing climate aff ects everyday life in Greenland. But the warmer climate may also allow for oil and mineral exploitation and new inter- continental shipping routes through Greenland waters where heavy ice cover once prevented these activities. Substituting space for time – Greenland 7 8 Substituting space for time – Greenland The Greenland coast spans more than 22 degrees of latitude from sub-Arctic to high-Arctic environments. Studying the marine ecosystem along this climatic gradient can give us an indication of what to expect in a warmer future. For example we expect the climate (temperature, ice cover, etc.) in the Disko Bay to resemble the conditions we now fi nd further south in Nuuk by the end of the century. Substituting space for time – Greenland 9 Qaanaaq Qaanaaq Disko Bay Disko Bay Nuuk Nuuk 0 50 100 150 200 250 300 350 Open-water period with light (days) 10 5 0 –5 Nuuk –10 Disko Bay –15 –20 Qaanaaq Average monthly temperature (°C) monthly temperature Average –25 J FMAMJ J A SOND Month 10 Substituting space for time – Greenland Ocean currents and air temperature creates diff erent sea-ice regimes and water temperatures along the coast of Greenland. The sub-Arctic conditions with warm water and low sea-ice cover is expected to expand northward in the future due to climate change. Substituting space for time – Greenland 11 70 °N 65 °N 60 °N 55 °N 50 °N 50 °W 40 °W 30 °W 20 °W 10 °W –1 0 1 2 3 4 6 8 10 12 °C 12 Substituting space for time – Greenland Substituting space for time – Greenland 13 14 Substituting space for time – Greenland Substituting space for time – Greenland 15 Open-water period with light 1.2 24 Qaanaaq 1.0 18 0.8 0.6 12 0.4 6 0.2 0 0 1.2 24 Disko Bay 1.0 18 0.8 0.6 12 0.4 Sea index ice 6 (hours) Daylight 0.2 0 0 The combination of sea ice cover 1.2 24 Nuuk (blue line) and polar day lengths 1.0 18 (yellow area) create latitudinal 0.8 diff erences in the duration of the 0.6 12 productive period (white area) 0.4 where sun-light penetrates the sea 6 0.2 surface and provides energy for 0 0 plankton and kelp. J FMAMJ J A SOND Month 16 Substituting space for time – Greenland Substituting space for time – Greenland 17 18 Substituting space for time – Greenland Substituting space for time – Greenland 19 20 Substituting space for time – Greenland Substituting space for time – Greenland 21 Siorapaluk Qaanaaq Dundas Young Sound Upernavik Uummannaq The longer productive period Disko Bay in southern Greenland allows Eqalunguit kelp to extend deeper and Itelleq grow larger. Nuuk 22 Substituting space for time – Greenland In Young Sound, NE Greenland, where climate monitoring has taken place since 2003 data show that kelp grow more in years with long duration of open water. This confi rms the pattern from the latitudinal study. 20 Young Sound 2003 15 2009 2010 2005 10 2007 2008 2011 Blade biomass (g C) Blade biomass 5 2004 Spheric 2006 R2 = 0.47 0 80 100 120 140 160 180 200 Open-water period with light (days) Substituting space for time – Greenland 23 24 Substituting space for time – Greenland Substituting space for time – Greenland 25 The reduction in sea ice cover has direct impacts on the animals that rely on sea ice as their main habitat such as walruses, polar bears and ice algae. However, the sea ice also modifi es the physical environment which can have pronounced impacts throughout the marine ecosystem. 26 Substituting space for time – Greenland Substituting space for time – Greenland 27 Cockles and sea urchins rely on phytoplankton and kelp for food. In high- Arctic Greenland they are food-limited Qaanaaq most of the year and consequently grow Young Sound slowly. In southern Greenland low sea-ice cover results in an extended productive period, leading to higher growth rates of Disko Bay these organisms. Nuuk 100 100 Bivalve Sea urchin 80 80 60 60 40 40 20 20 Relative growth performance (%) performance growth Relative (%) performance growth Relative 0 0 0 50 100 150 200 250 300 350 0 50 100 150 200 250 300 350 Open-water period with light (days) Open-water period with light (days) 28 Substituting space for time – Greenland By measuring growth rings in the shell of cockles it is possible to reconstruct past growth rates and show that shell growth is faster in years with less sea ice. As for the kelp, the time series of couples from Young Sound confi rms the relationship between sea ice and productivity. Substituting space for time – Greenland 29 Based on these studies we expect higher productivity of the coastal ecosystem in northern Greenland in a warmer future with less sea ice. However, the loss of sea ice is also a loss of the habitat that characterises the Arctic. With the continued loss of sea ice the high-Arctic marine ecosystem is shrinking and moving further north to smaller and smaller areas near the North Pole. 1.5 1.0 1996 1985 0.5 1979 1998 1991 1984 0 1994 1982 1992 1995 1980 1986 1983 1997 1993 –0.5 1987 1990 1981 Growth index 1988 1989 –1.0 –1.5 0.65 0.70 0.75 0.80 0.85 0.90 Sea ice index 30 Substituting space for time – Greenland Substituting space for time – Greenland 31 One of the aims of the Arctic Tipping Points project was to collect the available evidence in the scientifi c literature on how climate change has aff ected the Arctic marine ecosystem. Although we found numerous examples from all levels of the food chain, it is also evident that almost no examples are found in the central Arctic Ocean and from the Russian part of the Arctic. Large parts of the Arctic are still poorly studied and dramatic changes in the marine ecosystem are mostly likely taking place right now without us knowing it. 32 Substituting space for time – Greenland Substituting space for time – Greenland 33 Predicting impacts of climate change in Greenland: Photo credits: Substituting space for time Credit to Hurtigruten Marsel van Oosten (p. 1, 2, 3, 4, 6, 12, 14, 16, 18, 24, 32) By: Peter Bondo Christensen (p. 20, 23, 26) Mikael K. Sejr1, Dorte Krause-Jensen2 and Paul E. Renaud3 Mikael K. Sejr (p. 19, 28) 1 Aarhus University, Arctic Research Centre, Denmark Scientifi c details can be found in: 2 Aarhus University, Department of Bioscience, Denmark 3 Fram Centre for Climate and the Environment, Blicher, M.E., Rysgaard, S., Sejr M.K. (2007) Akvaplan-niva, Norway Growth and production of sea urchin Strongylocentrotus droebachiensis in a high-Arctic fj ord, and growth along a Graphic design: climatic gradient (64 to 77 degrees N). Juana Jacobsen, AU Bioscience Graphics Group Mar Ecol Prog Ser 341:89-102. Publisher: Sejr, M.K., Blicher, M.E., Rysgaard, S. (2009) Aarhus University, Department of Bioscience Spatial and temporal variation in sea ice cover infl uence annual growth of the Arctic cockle Clinocardium ciliatum Published 2013 in Greenland. ISBN 978-87-93129-02-3 Mar Ecol Prog Ser 389:149-158. Wassmann, P., Duarte, C.M., Agusti, S., Sejr, M.K. (2011) Footprints of climate change in the Arctic marine Scientifi c contributers: ecosystem. Martin Blicher Global Change Biology 17:1235-1249. Núria Marbà Birgit Olesen Krause-Jensen, D., Marbà, N., Olesen, B., Sejr, M.K., Peter Bondo Christensen Christensen, P.B., Rodrigues, J., Renaud, P.E., Balsby, Søren Rysgaard T.J.S., Rysgaard, S. (2012) João Rodrigues Seasonal sea ice cover as principal driver of spatial Susana Agusti and temporal variation in depth extension and annual Paul Wassmann production of kelp in Greenland. Carlos Duarte Global Change Biology 10:2981-2994. Substituting space for time – Greenland.