1 Global Warming –Beyond CO 2 : The Chilling Stars Henrik Svensmark, Center for Sun Climate Research Danish National Space Center Basel 2007

2 Global surface temperature

3 How STARS influence Climate

4 Heliosphere, Cosmic Rays and Solar Activity

5 Cosmic ray shower About 70 muons/s /m 2 at the Earths surface In 24 hours about 12 million muons goes through a human body

6 Cosmic Rays in a Cloud Chamber

7 Cosmic rays and climate over the last millennium

8 Cosmic rays and climate over the last years Bond et al, Science 294, 2001 Last 1000 years Little Ice Age Little Ice Age is merely the most recent of a dozen such events during the last years

9 Indian Ocean monsoon Solar/GCR forcing of Indian Ocean monsoons on centennial—even decadel—timescales

10 Solar/GCR signal in 20th century warming

11 Summary Evidence for GCR-climate association on all timescales of Earth’s history Diversity and quality of evidence appears to exclude mere chance association Key challenge is to establish the physical mechanism

12 Possible physical mechanism Mechanism that amplifies tiny GCR energy input

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14 Solar variability No evidence for long-term variations of solar irradiance /UV beyond 11-yr cycle Recent factor 5 reduction of estimated solar variability since Maunder Minimum (LIA)

15 Coronal Mass Ejections (CME) One month of observation

16 Increase in open solar magnetic flux over the past century Lockwood, Stamper, & Wild, Nature, Magnetic flux has increased a factor of 2.3 over the last 100 years Since 1963 an increase of 1.4 Open solar magnetic flux back in time reconstructed from geomagnetic activity

17 Global surface temperature

18 Svensmark & Friis-Christensen, JASTP 1997, Svensmark, PRL 1998, Marsh & Svensmark, PRL, (update 2005) Link between Low Cloud Cover and Galactic Cosmic Rays?

19 Clear association of climate change and 10 Be / 14 C variability (cosmic rays): Monsoon rainfall seems especially sensitive But is 10 Be / 14 C variability indicating a direct effect of cosmic rays on climate? or a proxy for solar variability (irradiance / UV)? high cosmic ray fluxcool climate low cosmic ray fluxwarm climate

20 Location of the Solar systems in the Milky Way Relevant for climate?

21 Earth’s climate the last 500 million years Veizer, et al. Nature 2000

22 Cosmic rays and spiral arm crossing Shaviv, PRL (2002) Million of Years Estimated Cosmic Ray Flux

23 Shaviv & Veizer Million of Years Estimated Cosmic Ray Flux Sea Surface Temperature Anomaly 0C0C Cosmic rays and spiral arm crossing

24 Gennem 500 millioner år har fossiler gemt information, i deres skaller, om hvor varmt det var da de levede Jordens temperatur gennem 500 millioner år

25 What about longer time scales, i.e over the history of the Earth 4.6 Billion years? Although Cosmic ray fluxes are not known so far back in time, they can be constructed from knowledge of 1.Solar Evolution 2.History of Star Formation Rate in the Milky Way

26 Solar Evolution, Star Rate Formation and Cosmic Rays SFR CR Outside the Heliosphere At Earth CR Svensmark, 2003

27 Interaction between galaxies

28 Cosmic Rays in 4 Billion Years Svensmark, GeV C = 0.92

29 If more carbon is stored in one of these reservoirs, the isotopic composition of others reservoirs changes to reflect that storage. For instance: if there is more carbon stored in organic matter which is isotopically light, the average carbon composition of dissolved carbon in the ocean and carbon dioxide in the atmosphere will become heavier. Carbon Isotopes The various reservoirs of carbon on Earth (limestone, biota and CO 2 in atmosphere)

30 Svensmark, Submitted PRL 2005 Carbon 13 during 3.8 billion years Standard deviation In steps of 400 mill yr

31 Cosmic Rays in 4 Billion Years Svensmark, Submitted PRL GeV C = 0.92

32 Cold Climate Equator Pole Ice Warm Cold Large temperature difference between equator and pole Strong winds – Mixing of Nutriants Large biological productivity Large fluctuations biological productivity possible

33 Hot Climate Equator Pole Hot Warm Small temperature difference between equator and pole Weak winds – Little Mixing of Nutriants Small biological productivity Small fluctuations in biological productivity

34 Conclusion Particles from space seems to influence Earths climate, ranging from years to 10 9 years. A part of the missing physical mechanism has been demonstrated experimentally Involving ions and aerosol formation Linking to clouds and thereby the energy budget of the Earth Understanding the cosmic ray climate link could have large implications in our understanding of climate changes and possible evolution on Earth. The evolution of the Milky Way and the Earth is linked It is not suggested that it is the only cause of climate change.

35 IPCC: Model beregninger af Jordens skydække Skydække i %

36 Temperatur udviklingen i atmosfæren: Observationer og modellering fra 49 ”eksperimenter” med 19 klimamodeller Overflade Nedre troposfære Middel af troposfære Øvre troposfære Temperature Trends in the Lower Atmosphere: Steps for Understanding and Reconciling Differences, 2006

37 Solar activity (October 2003) EUV (1.5 mill K)

38 Cosmic rays and climate over the last years