Klimawissenschaft – eine Spielart der

Physik?

Hans von StorchInstitut für

Küstenforschung

Hans von Storch

• Klimaforscher• Spezialgebiet: Küstenklima, also Windstürme, Sturmfluten, Seegang, Nordsee, Ostsee, Nordatlantik• Kooperation auch mit Sozial- und Geisteswissenschaftlern• Direktor des Instituts für Küstenforschung des Helmholtz Zentrums Geesthacht

Overview

• Climate Research – history• Physics of Climate• Problems – independence, experiments,

inhomogeneity of data, parameterizations• Postnormality – high uncertainty, high stakes• The knowledge market

Overview

• Climate Research – history• Physics of Climate• Problems – independence, experiments,

inhomogeneity of data, parameterizations• Postnormality – high uncertainty, high stakes• The knowledge market

Climate research – history

• Anthropocentric view – climate determines living conditions;

• Climatic determinism• Physics of atmosphere and of

ocean• Physics of climate• Climate change – climate

constrains living conditions

Alexander von Humboldt (1769–1859) Cosmos, A Sketch of a Physical Description of the Universe, 1845

“The term climate, taken in its most general sense, indicates all the changes in the atmosphere, which sensibly affect our organs, as temperature, humidity, variations in the barometrical pressure, the calm state of the air or the action of varying winds, the amount of electric tension, the purity of the atmosphere or its admixture with more or less noxious gaseous exhalations, and, finally, the degree of ordinary transparency and clearness of the sky, which is not only important with respect to the increased radiation from the earth, the organic development of plants, and the ripening of fruits, but also with reference to its influence on the feelings and mental condition of men”.

Climatic determinism

civilization

climatic energy

Ellsworth Huntington

1876–1947 of Yale University

Atmospheric and oceanic dynamics

Climate physics

mitigation, adaptation costs

policies

after Hasselmann, 1990

Climate change – climate constrains living conditions

Overview

• Climate Research – history• Physics of Climate• Problems – independence, experiments,

inhomogeneity of data, parameterizations• Postnormality – high uncertainty, high stakes• The knowledge market

Global temperature derived from thermometer data (CRU)

IPCC 2007

Explaining global mean surface air temperature

Auch mensch-gemachte Treibhausgase

Nur natürliche Faktoren

Messungen

Scenarios, not predictions

Overview

• Climate Research – history• Physics of Climate• Problems – independence, experiments,

inhomogeneity of data, parameterizations• Postnormality – high uncertainty, high stakes• The knowledge market

The space-and time-scales of atmospheric and oceanic dynamics

atmosphere

Dynamical processes in a global atmospheric general circulation model

Need for parametrising the effect of non-resolved dynamics on the resolved dynamics.

e.g., by specifying the expected effect due to small-scale dynamics conditional upon the large scale (resolved) state.

Alternative: choose randomly an effect observed under the given large-scale state.

The limit x0 is not defined for parameterizations; there is no known limiting equations.

This part is called physics in the slang of atmospheric and oceanic scientists (as opposed to the revolved dynamics).

Data, independent observations, experiments

• All data are dependent on each other; maybe every 30 years, or so, we are able to observe a new somewhat independent realization of the climate system.

• Only one world, thus truly independent data for falsifying hypotheses is generated at very slow pace.

• Real experiments hardly possible (except for in models as virtual realities)

• Reliance on past data – instrumental and indirect (proxy)

• Causes of inhomogenities:• Changes in

– Instruments– Sampling frequencies – Measuring units– Environments (e.g.

trees, buildings)– Location

Station relocations (Dotted lines)

Representativity of near surface wind speed measurements

1.25 m/s

J. Lindenberg, 2010

Representativity of near surface wind speed measurements

J. Lindenberg, 2010

Counting storms in weather maps – steady increase of NE Atlantic storms since the 1930s ….

Historical data - inhomogeneity

Overview

• Climate Research – history• Physics of Climate• Problems – independence, experiments,

inhomogeneity of data, parameterizations• Postnormality – high uncertainty, high stakes• The knowledge market

Postnormal science

Jerry Ravetz, Silvio Funtovicz, 1986 and earlier

State of science, when facts uncertain, values in dispute, stakes high and decisions urgent.

In this state, science is not only done for reasons for curiosity but is asked for as support for preconceived value-based agendas.

facts uncertain: e.g. sensitivity of global mean temperature to doubling of CO2 concentration

values in dispute, e.g., do we cement the world according to our present preferences or do we accept a generationally dynamical development?

stakes high, e.g., costs for re-organizing global energy market and future damages

decisions urgent, e.g., to be efficient, re-organization of e.g., traffic must be begun now.

mitigation, adaptation costs

policies

Overview

• Climate Research – history• Physics of Climate• Problems – independence, experiments,

inhomogeneity of data, parameterizations• Postnormality – high uncertainty, high stakes• The knowledge market

Lund and Stockholm

Two different construction of „climate change“ – scientific and cultural – which is more powerful?

Cultural: „Klimakatastrophe“

Scientific: man-made change is real, can be mitigated to some extent but

not completely avoided

Storms

• 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.• The 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.

• The social process „science“ is influenced by these other knowledge forms.

• Science can not be objective but should nevertheless strive to be so.

Knowledge market

And physics …?• Climate science comprises a large segment which is essential a type of physics

• Climate science is of great technical importance, for issues of mitigation and even more so for adaptation – and thus a type of engineering.

• But climate science is embedded in a politico-cultural context, which makes climate science post-normal.

• Thus climate science as a whole is not “just” another type of physics, but a social process significantly different from conventional physics.

Climate Sciences …• … comprise much more issues than the geophysical issues

of fluid dynamics and thermodynamics forcing.• Impacts of climate variability and change are in the focus of

academic interest, which is driven not only by scientific understanding but also by media constructions and value-based assumptions.

• “Climate” has very much to do with what is culturally believed and understood - both in the public and among scientific actors.

• “Climate” must therefore become a field of active social- and cultural research on the functioning of science-society interactions and scientific practice.

• Climate Science is much more than Physics.

Take home …• The basic physical understanding is not contested

(humans > CO2/GHG > warming).• Many secondary effects (e.g., ice sheets, hurricanes) still

under analysis.• Regional manifestation and impacts still under analysis.• 2-degree goal is a political goal, not a scientifically

determined goal.• Climate science operates under post-normal conditions,

i.e., the differences between political actors and scientific actors blurr.

• Critical questioning (by skeptics) is legitimate and helpful.• Climate science needs critical analysis by cultural

sciences.

http://coast.gkss.de/staff/storchhvonstorch@web.de

Weblog KLIMAZWIEBELhttp://klimazwiebel.blogspot.com/