Hans von Storch Geesthacht , Hamburg and Qingdao

1. Scientific and social constructions of climate change – What are you more interested in predicting: climate change policy or climate change? Hans von Storch Geesthacht, Hamburg and Qingdao 9. May 2019 - Forum der Europäischen Fracht und Logistikindustrie (F&L) / Weltwirtschaftsforum, Hamburg

2. Hans von Storch Climate researcher (in the field since 1971) Coastal climate (storms, storm surges, waves; North and Baltic Sea, North Atlantic, Yellow Sea); statistical analysis Director emeritus of the Institute of Coastal Research of the HelmholtzZentrum Geesthacht, Germany Professor at Universität Hamburg andat the Ocean University of China Editor-in-chief of the Oxford University Press Research Encyclopedia on Climate Science Lead authorof IPCC AR3 and AR5. Co-Chair of regional assessmentreportsBaltic SeaCatchment (BACC) and of Hamburg Metropolitan Region http://www.hvonstorch.de/klima/

3. Overview • Knowledge as constructions • Scientific construction of climate change • Size of the climate problem • Social constructions of climate change • Climate policy – driven by the social constructions

4. Knowledge is constructed • Knowledge is defined here as „ability to make sense“, and not an indication of knowing the „truth“. • Knowledge is power, claims of knowledge are claims of power. • There are various forms of knowledge about the same issue. • Scientific knowledge is one type of knowledge. • Scientific knowledge does not necessarily win public acceptance. • Constructions are not arbitrary, but based on previously formulated explanations (theories), interpretations of earlier events and recent observations. • Constructions are based on assumptions, which are consistent with cultural contexts and social preferences. • Knowledge is scientific, if it is constructed using the scientific method, not by an acclamation of scientists. • The scientific construction has been prepared by actors who adhere to the CUDOs norms – collective ownership by the scientific community, independent of the constructing persons, without external interests, and critically reviewed by the scientific community. • Scientific constructions are consistent with the interpretation of other phenomena and all relevant observations.

5. Key finding of Working Group I of the IPCC. • Temperatures rise almost everywhere, however with different speeds. • Without a dominant contribution by greenhouse gases an explanation of this warming is not possible at this time.

6. The present scientific construction Within the scientific community there is consensus: • There is a global warming, which is inconsistent with internal causes (detection) • Thus, the warming needs an explanation byexternal causes. Only when greenhouse gases are considered a dominant driver, a consistent explanation can be found (attribution) • The change manifests itself in the thermal regime including diminishing (Northern Hemisphere) sea-ice cover, in sea level rise and, plausibly, in more heavy rainfall events. • Many details are uncertain, such as • the speed of rise of global sea level and of temperature, • the regional and local manifestations, and • the co-effect of different “drivers” (say, greenhouse gases, aerosols, land use change incl. urban effects) This scientific construction of the anthropogenic climate change is broadly supported among climate scientists. It is documented by the collective efforts of the Intergovernmental Panel on Climate Change (IPCC).

7. Size of the climate problem The atmospheric concentration of CO2 has grown from about 280 ppm in 1850 to 410 ppm – due to anthropogenic emissions. These concentrations are small compared to other constituents of air, but go with a significant impact on the thermal structure of the climate system. The concentration will begin to no longer grow only after all human emissions of carbon have come to an end.

8. Emissions and temperature increase The increase of global mean temperature is about proportional to the amount of carbon dioxide released into the atmosphere, with about 2 10-5K per MtCO2 “budget concept”). IPCC, AR5, 2013 Present emissions in Germany: about 0.8 year. (UBA)

9. Scenarios of emissions which would allow meeting the 1.5 K goal. Policy Maker Summary of IPCC Report on Global warming of 1.5C Figueres, C., H.J. Schellnhuber, J. Rockström, A. Hobley, und S. Rahmstorf, 2017: Three years to safeguard our climate. Nature 546, 593pp

10. Climate change and stakeholders • Climate change goes along with changes in the geophysical conditions, in changing hazards and opportunities. • Particularly severe are the effects of rising sea level, the intensification of the water cycles and the loss of sea ice. • Stakeholders are economies, political systems, and the general public. • Political deciders, in consistence with the general public, have decided that climate change must be limited to a 1.5o level (Paris accord). • Even if such an ambitious goal is reached, a number of visible changes in the geophysical system will emerge, and societies and ecosystems will need to adapt. • If this goal is not reached, more damages must be responded to.

11. Climate science in global societies Perceived environment and society model (von Storch, ca. 1992) Global environment and society model (Hasselmann, ca. 1990)

12. Knowledge competition: - The present scientific construction - Dominant present cultural construction: Climate catastrophe - Cultural constructions: Nature strikes back - Skeptics - Outdated scientific constructions

13. Knowledge competitionDominant present cultural construction: Climate catastrophe According to this construction, climate is changing because of human activities. The weather is less reliable than in earlier times; the seasons are unsteady, storms more violent. Climatic extremes take on catastrophic, never seen dimensions. The factors, leading to this change, are related to „our greed and stupidity“. Sometimes, justice is a significant mechanism, sometimes the revenge of nature for human environmental sins. Also, the changes are considered to reflect good‘s wrath. This climate catastrophe may be averted by keeping the change within the 2o limit. Reaching this goal depends crucially on the engagement of the individuals (abstinence of air travel, usage of bikes, vegetarian food; good example for other people.)

16. Knowledge competitionOutdated scientific constructions • Climatic determinism – climate as a key factor determining the development and fall of civilizations, the level of criminal activity, for the superiority of certain world regions, for societal violence, ability to learn and usage of libraries. This theory was used as a legitimation of colonialism, and is implicit in scenarios of contemporary climate change scenarios. • Humans have to live in „harmony“ with „their“ climate; any disturbance of this balance will lead to serious repercussions in the life of people and the success of civilizations. Map of „mental energy“ conditioned by climatic conditions Distribution of civilizations in 1916, according to expert opinions. Stehr, N., and H. von Storch, 1999: An anatomyofclimatedeterminism. In: H. Kaupen-Haas (Ed.): Wissenschaftlicher Rassismus - Analysen einer Kontinuität in den Human- und Naturwissenschaften. Campus-Verlag Frankfurt.a.M. - New York (1999), 137-185, ISBN 3-593-36228-7 Ellsworth Huntington,ca. 1917

17. The science-policy/public interaction is not an issue of „knowledge speaks to power“. The problem is not that the public is stupid or uneducated. A problem is that the scientific knowledge is confronted on the „explanation marked“ with other forms of knowledge (pre-scientific, outdated, traditional, morphed by different interests). Scientific knowledge does not necessarily “win” this competition. A problem is that science is presented as if there were a well-defined problem, which needs one specific “solution”. The social process „science“ is influenced by these other knowledge forms. Knowledge market

18. Take home: Climate science and knowledge • Climate science offers robust answers to the key questions on climate change, namely on the reality of warming, the presence of external causes, and attribution of greenhouse gases to be the dominant cause of the change, and the possibility to limit climate change by reducing or out-phasing CO2 emissions. Other questions are still contested. • Climate science supports the political process of the formation of a democratic will. The results of this political process, however, is a matter of social negotiation processes. • Climate science is in a “post-normal” state, where the political utility of scientific knowledge is more important that methodical rigor, and where political actors claim that their „good“ case is coercively supported by science. • There is a plethora of knowledge claims, which influence the understanding and deciding by stakeholders, media and public. The scientifically constructed knowledge does not necessarily win this competition.

19. Main conclusion • The political decision processes are mostly steered by social constructions of climate change, social preferences and wishful thinking – but only loosely connected to the scientific (de)construction of ongoing and expected geophysical change. • Thus, political decisions are not determined by scientific knowledge about ongoing climate change, but other social factors are decisive. • Changing political wills result in the formation of regulations (such as banning certain fuels) and preferences, with significant consequences for economic actors. • Some geophysical changes may be of direct impact for your industry, such as road conditions or ice-free passages – and will require responses for exploiting beneficial change and adapting to adverse conditions.