Klimaänderung. Robert Sausen Deutsches Zentrum für Luft- und Raumfahrt Institut für Physik der Atmosphäre Oberpfaffenhofen

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1 Klimaänderung Robert Sausen Deutsches Zentrum für Luft- und Raumfahrt Institut für Physik der Atmosphäre Oberpfaffenhofen Vorlesung WS 2017/18 LMU München

2 6. Kohlenstoff- und andere biogeochemische Kreisläufe

3 Contents of IPCC 2013 Working Group I: the Physical Science Basis

4 Contents of IPCC 2013 Working Group I: the Physical Science Basis

5 The basis for the confidence level IPCC 2013, Chap

6 Likelihood terms IPCC 2013, Chap. 1

7 Statements in the Executive Summary The Human-Caused Perturbation in the Industrial Era (1) CO 2 increased by 40% from 278 ppm about 1750 to ppm in During the same time interval, CH 4 increased by 150% from 722 ppb to 1803 ppb, and N 2 O by 20% from 271 ppb to ppb in It is unequivocal that the current concentrations of atmospheric CO 2, CH 4 and N 2 O exceed any level measured for at least the past 800,000 years, the period covered by ice cores. Furthermore, the average rate of increase of these three gases observed over the past century exceeds any observed rate of change over the previous 20,000 years. Anthropogenic CO 2 emissions to the atmosphere were 555 ± 85 PgC (1 PgC = gc) between 1750 and With a very high level of confidence, the increase in CO 2 emissions from fossil fuel burning and those arising from land use change are the dominant cause of the observed increase in atmospheric CO 2 concentration. About half of the emissions remained in the atmosphere since Carbon emissions from fossil fuel combustion and cement production increased faster during the period than during the period

8 Statements in the Executive Summary The Human-Caused Perturbation in the Industrial Era (2) Atmospheric CO 2 concentration increased at an average rate of 2.0 ± 0.1 ppm yr 1 during This decadal rate of increase is higher than during any previous decade since direct atmospheric concentration measurements began in

9 Simplified schematic of the global carbon cycle

10 Black: reservoir mass and exchange fluxes prior to the Industrial Era, about 1750 Red reservoirs: cumulative changes of anthropogenic carbon Red arrows: annual anthropogenic fluxes averaged

11 Main natural processes that remove CO

12 Percentage of emitted CO 2 remaining in the atmosphere in response to an idealised instantaneous CO 2 pulse emitted

13 Atmospheric concentrations of CO 2, oxygen, 13 C/ 12 C stable isotope ratio in CO 2, CH 4 and N 2 O

14 Statements in the Executive Summary The Human-Caused Perturbation in the Industrial Era (2) Atmospheric CO 2 concentration increased at an average rate of 2.0 ± 0.1 ppm yr 1 during This decadal rate of increase is higher than during any previous decade since direct atmospheric concentration measurements began in After almost one decade of stable CH 4 concentrations since the late 1990s, atmospheric measurements have shown renewed CH 4 concentrations growth since The concentration of N 2 O increased at a rate of 0.73 ± 0.03 ppb yr 1 over the last three decades. The human-caused creation of reactive nitrogen in 2010 was at least two times larger than the rate of natural terrestrial creation

15 Simplified schematic of the global methane cycle Black: natural fluxes Red: anthropogenic fluxes Brown: combined natural + anthropogenic flux

16 Atmospheric concentrations of CO 2, oxygen, 13 C/ 12 C stable isotope ratio in CO 2, CH 4 and N 2 O

17 Global anthropogenic CO 2 budget

18 Statements in the Executive Summary Before the Human-Caused Perturbation During the last 7000 years prior to 1750, atmospheric CO 2 from ice cores shows only very slow changes (increase) from 260 ppm to 280 ppm, in contrast to the human-caused increase of CO 2 since pre-industrial times. The contribution of CO 2 emissions from early anthropogenic land use is unlikely sufficient to explain the CO 2 increase prior to Atmospheric CH 4 from ice cores increased by about 100 ppb between 5000 years ago and around Further back in time, during the past 800,000 years prior to 1750, atmospheric CO 2 varied from 180 ppm during glacial (cold) up to 300 ppm during interglacial (warm) periods

19 IPCC 2013, Chap

20 Mechanisms contributing to carbon dioxide concentrations changes

21 CO 2, CH 4, and N 2 O concentrations during the Holocene

22 Sausen, Klimaänderung 1.6 IPCC 2013, Chap. 5 Orbital parameters and proxy records over the past 800 kyr

23 Statements in the Executive Summary Future Projections