Spatial Impacts of Climate Change. Denis Mercier

of Arctic climate warming

       (source: design D. Mercier, drawing by F. Bonnaud, Faculty of Arts, Sorbonne University, 2020). For a color version of this figure, see www.iste.co.uk/mercier/climate.zip

      In addition to albedo, Figure 1.12 illustrates the major components of the Earth's radiation budget, which is simplified by an average solar energy input of 342 watts per square meter to the Earth's surface. The percentages of each component (clouds, ocean, land surface, atmosphere) show that only 47% is absorbed (25% by the oceans and 22% by land surfaces). In the evolution of temperature in the lower layers of the atmosphere, the cloud component plays a fundamental role because it absorbs part of the energy (19%) and reflects 20%. Cloud cover and its temporal evolution therefore appear to be an essential element in understanding the evolution of the radiation balance on the Earth's surface.

1.6. Conclusion

Contemporary climate change is illustrated by recognized and measured thermal and rainfall trends that are neither linear over time nor spatially uniform. Beyond the general logics of the physical laws governing the climate machine on a global scale (radiation balance, importance of astronomical parameters, role of greenhouse gases and volcanism, thermal gradients, air humidity capacity, etc.), regional and local nuances illustrate the importance of geographical factors and interactions between all components, such as the fundamental Arctic-wide interaction between the ocean, sea ice and the atmosphere. Whether during the cold Pleistocene sequences or during contemporary global warming, we are seeing an amplification of changes in high-latitude environments, particularly in the Arctic Basin.

1.7. References

      AMAP (2017). Snow, Water, Ice and Permafrost in the Arctic (SWIPA). Arctic Monitoring and Assessment Programme (AMAP), Oslo.

      Bethke, I., Outten, S., Ottera, O.H., Hawkins, E., Wagner, S., Sigl, M., Thorne, P. (2017). Potential volcanic impacts on future climate variability. Nature Climate Change, 7(11), 799-805.

      Bourriquen, M., Mercier, D., Baltzer, A., Fournier, J., Costa, S., Roussel, E. (2018). Paraglacial coasts responses to glacier retreat and associated shifts in river floodplains over decadal timescales (1966-2016), Kongsfjorden, Svalbard. Land Degradation and Development, 29(11), 4173-4185.

      Cheng, L., Abraham, J., Zhu, J., Trenberth, K.E., Fasullo, J., Boyer, T., Locarnini, R., Zhang, B., Yu, F., Wan, L., Chen, X., Song, X., Liu, Y., Mann, M.E. (2020). Record-setting ocean warmth continued in 2019. Advances in Atmospheric Sciences, 37, 137-142.

      Forland, E.J., Benestad, R., Hanssen-Bauer, I., Haugen, J.E., Skaugen, T.E. (2012). Temperature and precipitation development at Svalbard 1900-2100. Advances in Meteorology, 2011(17).

      Hanssen-Bauer, I., Forland, E.J., Hisdal, H., Mayer, S., Sand0, A.B., Sorteberg, A. (2019). Climate in Svalbard 2100 - A knowledge base for climate adaptation. Report, 1/2019, NCCS.

      Humlum, O., Solheim, J.-E., Stordahl, K. (2011). Spectral analysis of the Svalbard temperature record 1912-2010. Advances in Meteorology, 2011.

      IPCC (2014). Climate Change 2014: Synthesis report. Contribution of working groups I, II and III to the fifth assessment report of the Intergovernmental Panel on Climate Change. Report, IPCC, Geneva.

      IPCC (2019). Special report on the ocean and cryosphere in a changing climate. [Online]. Available at: https://www.ipcc.ch/srocc.

Khodri, M., Swingedouw, D., Mignot, J., Sicre, M.A., Garnier, E., Masson-Delmotte, V.,

      Ribes, A., Terray, L. (2015). Le climat du dernier millénaire. La Météorologie, 88, 36-47.

      Lageat, Y. (2019). Les variations du niveau des mers. Presses Universitaires de Bordeaux, Pessac.

      Masson-Delmotte, V., Braconnot, P., Kageyama, M., Sepulchre, P. (2015). Qu'apprend-on des grands changements climatiques passés ? La Météorologie, 88, 25-35.

      Solheim, J.-E., Stordahl, K., Humlum, O. (2011). Solar activity and Svalbard temperatures. Advances in Meteorology, 2012.

      Stoffel, M., Khodri, M., Corona, C., Guillet, S., Poulain, V., Bekki, S., Guiot, J., Luckman, B.H., Oppenheimer, C., Lebas, N., Beniston, M., Masson-Delmotte, V. (2015). Estimates of volcanic-induced cooling in the Northern Hemisphere over the past 1,500 years. Nature Geoscience Letters, 8(10), 784-788.

      Toohey, M. and Sigl, M. (2017). Volcanic stratospheric sulfur injections and aerosol optical depth from 500 BCE to 1900 CE. Earth System Science Data, 9, 809-831 [Online]. Available at: https://doi.org/10.5194/essd-9-809-2017.

      Toohey, M., Krüger, K., Sigl, M., Stordal, F., Svensen, H. (2016). Climatic and societal impacts of a volcanic double event at the dawn of the Middle Ages. Climatic Change, 136, 401-412.

      WMO (2019). The state of greenhouse gases in the atmosphere based on global observations through 2018. Greenhouse Gas Bulletin, 15.

      1 1 https://public.wmo.int.fr.

      2 2 Zetta: one trilliard (1021) or one thousand trillion, according to the international system of units.

      3 3 http://www.climate4you.com/SvalbardTemperatureSince1912.htm.

      4 4 Representative Concentration Pathway (RCP), scenario expressed in watts per square meter.

      2

      Climate Change and the Melting Cryosphere

       Denis Mercier

       Sorbonne University, Paris, France

2.1. Introduction

      Contemporary climate change affects the cryosphere; the thermal changes at stake today are limited compared to the great climatic oscillations that affected the Earth, particularly during the past 2.58 million years of the Quaternary Period. Indeed, the areas concerned, and the volumes of ice are undeniably not of the same order of magnitude. During the great cold periods of the Pleistocene (2,580,000 to 11,700 years ago), the terrestrial cryosphere capitalized on the planet’s land spaces led to an eustatic decrease of around 120 to 130 m in the global ocean. In retrospect, during previous interglacial periods such as the Eemian (128,000 to 116,000 years ago), the temperature was around 3.5°C higher than today’s, which led to a significant melting of the terrestrial cryosphere and a rise in the average sea and ocean level of between 6.6 and 9.4 m above the current level (Lageat 2019). We are now experiencing a few decimeters per century in sea level rise, as a result of the partial melting of what is currently left of the Earth’s cryosphere. However, over the next several centuries, the continued melting of the cryosphere could bring the average sea and ocean level back to the Eemian level average, due in part to the melting of Greenland’s ice. However, the consequences of this current melting of the cryosphere due to warming air temperatures affect all components of the climatic and hydrological mechanics.

      Spatial Impacts of Climate Change, coordinated by Denis Mercier. © ISTE Ltd 2021.

2.2. The sensitivity of the cryosphere to climate change

The cryosphere is defined as the cold sphere (from the Greek kruos, the cold), and occurs on Earth in various forms from water to solid ice. These include the two ice sheets in Greenland and Antarctica, icecap glaciers such as Vatnajokull in Iceland, valley and cirque glaciers in