GEOL 437 Global Climate Change 2/22/18: Role of the Biosphere in the Climate System

Transcription

1 GEOL 437 Global Climate Change 2/22/18: Role of the Biosphere in the Climate System Role of the biosphere in the climate system Discussion of Cox et al (2000) What interactions dominate the results? What are the major uncertainties and how might they be addressed? Where does life fit into our picture of the climate system? AR5 WG1 Ch6: Carbon and other biogeochemical cycles: Ciais, P. et al, 2013: Carbon and Other Biogeochemical Cycles. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., et al (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, acc. 2/28/14.

2 Role of the Biosphere in the Climate System Key concepts Carbon-climate interaction Carbon-biogeochemistry interaction Fig 6.1, AR5 WG1 Ch6: Carbon and other biogeochemical cycles: Ciais, P. et al, 2013: Carbon and Other Biogeochemical Cycles. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., et al (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, acc. 2/28/14.

3 What's missing from our climate model? Atacama Desert photos from Atacama Desert Trek project webpages, 13/www/atacama-trek/photo_gallery/74.jpg, accessed 2/25/09

4 What's missing from our climate model? SeaWiFS chlorophyll-a retrieval (ocean) and NDVI (land) animation for (acc 2/22/18)

5 Where is life in the carbon balance? Ciais, et al, 2014, Fig 6.1

6 Carbon in the climate system: Processes and timescales Carbon-climate interaction: response of the climate to changes in atmospheric CO2 Ciais, et al, 2014, Table 1 in Box 6.1; see also drawn slides from 2/20/18

7 Simulation of carbon in the climate system Ciais, et al, 2014, Fig. 1 in Box 6.4

8 Simulation of carbon in the climate system Ciais, et al, 2014, Fig. 1 in Box 6.4

9 Dynamic vegetation in climate system models Schematic coupled climate-carbon cycle model from Cox et al., Hadley Center Technical Note #23, accessed via internet: 2/25/09

10 Dynamic land vegetation in climate system models TRIFFID structure for a single plant functional type, from Cox et al., Hadley Center Technical Note #23, accessed via internet: 2/25/09

11 Simulation of carbon dynamics in the climate system Observational estimates Ciais, et al, 2014, Fig. 6.24, panel a

12 Simulation of carbon dynamics in the climate system Comparison of TRIFFID output with observed soil carbon, from Cox et al., Hadley Center Technical Note #74, publications/hctn/. acc. 2/25/09

13 Simulation of carbon in the climate system Ciais, et al, 2014, Fig Biogeochemistry-climate interactions: response of the climate to biospheric activity

14 Role of the Biosphere: state of the art These numerical experiments demonstrate the potential importance of climate/carbon-cycle feedbacks, but the magnitude of these in the real Earth is highly uncertain. - P.M. Cox et al. (2000) Indeed, a harsh, but not entirely unwarranted, view would be that our current understanding of biosphere-atmosphere feedbacks is a collection of interesting, but largely untested, hypotheses for the future state of terrestrial ecosystems and climate. -P.R. Moorcroft (2006) In view of the large spread of model results and incomplete process representation, there is low confidence on the magnitude of modeled future land carbon changes... [T]here is no consensus on... open ocean [oxygenation] because of large uncertainties in potential biogeochemical effects and in the evolution of tropical ocean dynamics. - Ciais et al, Exec Summary, AR5WG1 Ch 6 (2014)

15 Summary Movement of carbon within the climate system creates interactions between atmospheric carbon, biological activity, and climate. Interactions between physical climate and atmospheric carbon are relatively well understood, but interactions with biological activity are only beginning to be understood. Next: Discussion of Cox et al (2000) What processes explain the results of Cox et al. (2000)? What are the major uncertainties? Next week: Feedbacks in the climate system