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MNP Rapport 500102001 Scientific Assessment of Solar Induced

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MNP Rapport 500102001 Scientific Assessment of Solar Induced CLIMATE CHANGE SCIENTIFIC ASSESSMENT AND POLICY ANALYSIS Scientific Assessment of Solar Induced Climate Change Report 500102001 Editor Dr. R. van Dorland Authors Prof. dr. C. de Jager Dr. G.J.M. Versteegh Dr. R. van Dorland This study has been performed within the framework of the Netherlands Research Programme on Climate Change (NRP-CC), subprogramme Scientific Assessment and Policy Analysis, project ‘Options for (post-2012) ClimateMarch Policies 2006 and International Agreement’ This study has been performed within the framework of the Netherlands Programme on Scientific Assessment and Policy Analysis for Climat Change Wetenschappelijke Assessment en Beleidsanalyse (WAB) Het programma Wetenschappelijke Assessment en Beleidsanalyse klimaatverandering in opdracht van het ministerie van VROM heeft tot doel: • Het bijeenbrengen en evalueren van relevante wetenschappelijke informatie ten behoeve van beleidsontwikkeling en besluitvorming op het terrein van klimaatverandering; • Het analyseren van voornemens en besluiten in het kader van de internationale klimaatonderhandelingen op hun consequenties. Het betreft analyse- en assessment werk dat beoogt een gebalanceerde beoordeling te geven van de stand van de kennis ten behoeve van de onderbouwing van beleidsmatige keuzes. Deze analyse- en assessment activiteiten hebben een looptijd van enkele maanden tot ca. een jaar, afhankelijk van de complexiteit en de urgentie van de beleidsvraag. Per onderwerp wordt een assessment team samengesteld bestaande uit de beste Nederlandse experts. Het gaat om incidenteel en additioneel gefinancierde werkzaamheden, te onderscheiden van de reguliere, structureel gefinancierde activiteiten van het consortium op het gebied van klimaatonderzoek. Er dient steeds te worden uitgegaan van de actuele stand der wetenschap. Klanten zijn met name de NMP-departementen, met VROM in een coördinerende rol, maar tevens maatschappelijke groeperingen die een belangrijke rol spelen bij de besluitvorming over en uitvoering van het klimaatbeleid. De verantwoordelijkheid voor de uitvoering berust bij een consortium bestaande uit MNP, KNMI, CCB Wageningen-UR, ECN, Vrije Universiteit/CCVUA, UM/ICIS en UU/Copernicus Instituut. Het MNP is hoofdaannemer en draagt de eindverantwoordelijkheid. Scientific Assessment and Policy Analysis The programme Scientific Assessment and Policy Analysis is commissioned by the ministry of the environment (VROM) and has the following objectives: • Collection and evaluation of relevant scientific information for policy development and decision–making in the field of climate change; • Analysis of resolutions and decisions in the framework of international climate negotiations and their implications. The programme is concerned with analyses and assessments intended for a balanced evaluation of the state of the art knowledge for underpinning policy choices. These analyses and assessment activities are carried out within several months to about a year, depending on the complexity and the urgency of the policy issue. Assessment teams organised to handle the various topics consist of the best Dutch experts in their fields. Teams work on incidental and additionally financed activities, as opposed to the regular, structurally financed activities of the climate research consortium. The work should reflect the current state of science on the relevant topic. The main commissioning bodies are the National Environmental Policy Plan departments, with the Ministry of Housing, Spatial Planning and the Environment assuming a coordinating role. Work is also commissioned by organisations in society playing an important role in the decision-making process concerned with and the implementation of the climate policy. A consortium consisting of the Netherlands Environmental Assessment Agency (MNP), the Royal Dutch Meteorological Institute, the Climate Change and Biosphere Research Centre (CCB) of the Wageningen University and Research Centre (WUR), the Netherlands Energy Research Foundation (ECN), the Netherlands Research Programme on Climate Change Centre of the Vrije Universiteit in Amsterdam (CCVUA), the International Centre for Integrative Studies of the University of Maastricht (UM/ICIS) and the Copernicus Institute of the Utrecht University (UU) is responsible for the implementation. The Netherlands Environmental Assessment Agency – MNP as main contracting body assumes the final responsibility. For further information: Netherlands Environmental Assessment Agency, WAB secretariate (ipc 90), P.O. Box 303, 3720 AH Bilthoven, tel. +31 30 274 3728, email: [email protected]. This report in pdf-format is available at www.mnp.nl This report was internally reviewed by Syun Akasofu, Galina Bazilevskaya, Jürg Beer, Maarten Blaauw, Raymond Bradley, Silvia Duhau, Bas van Geel, Peter Hoyng, Jos de Laat, Jan de Leeuw, Dimitri Mauquoy, Ron Moore, Raimund Muscheler, Enric Pallé, Karin Labitzke, Ulrike Langematz, Cor Schuurmans, Klairie Tourpali, Ilya Usoskin, Nigel Weiss and Karin Zonneveld. Acknowledgements The authors wish to thank the reviewers for their useful comments and their suggestions to improve the quality of this report. We also acknowledge the members of Club du Soleil and in particular the chairman, Jan de Leeuw (KNIOZ), for organising meetings with many opportunities to discuss the solar-terrestrial relationship. Club du Soleil is a Dutch virtual institute on solar variability and climate change with a multidisciplinary character, consisting of astronomers, meteorologists, climatologists, biologists, and earth scientists. Royal Netherlands Meteorological Institute (KNMI) Climate Research and Seismology Department Atmospheric Research Division P.O.Box 201 3730 AE De Bilt The Netherlands T: +31 30 2206775 E-mail: [email protected] Copyright © 2006, Netherlands Environmental Assessment Agency, Bilthoven All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without the prior written permission of the copyright holder. Preface The extent to which solar activity is a factor in climate change as compared to the human influence is a hot issue in climate research as well as in the public debate. In order to assess the understanding of the solar terrestrial relation, the Netherlands Programme on Scientific Assessment and Policy Analysis for Climate Change (WAB) requested the Royal Netherlands meteorological Institute (KNMI) in 2003 to coordinate a project, which should include an assessment on the knowledge of the solar dynamo, the proxy records as well as on the understanding of the possible and probable mechanisms of climate change due to changes in solar variability. Since the literature on this subject is growing almost exponentially, this is a hard task. Most problematic is the fact that a vast number of hypotheses are brought up lagging the ways to validate these theories. It is not easy to resist almost perfect correlations between (derived) solar parameters and climate change even without understanding the underlying mechanisms. The immediate thought is that if you see smoke there should be a fire. However, understanding the principles of climate change is crucial to make statements on cause-effects relations. It has often been stated that the climate system is far too complex to be conclusive at all. This may be objected by the fact that also very complex systems obey the laws of physics. For the climate system a very robust constraint is the conservation of energy: what is going in must go out, at least on average. However, defining this averaging period is a problem due to the large range of time-scales related to the processes in the climate system. Complex systems usually have non-linear and even chaotic behavior, resulting in the extreme case in no clear cause – effect relation. This is certainly the case if we try to forecast weather several days ahead, predicting the timing and location of pressure systems with their rainy frontal zones or in case of high pressure systems stable and mostly dry episodes. Uncertainties in the initial conditions result in growing errors with time, because small scale features are influencing large scale phenomena. Considering climate, the focus is on weather statistics. We actually remove the constraint on timing and location of pressure systems and try to find boundary conditions ruling average weather, i.e. the number and strength of storms or average temperatures occurring in a season. One of the boundary conditions is the change of energy flows at the top of atmosphere, referred to as radiative forcing. There is ample evidence that at least in the last few millennia radiative forcing and climate change are linked in an approximate linear way. This implies that the change in weather statistics can be described in terms of changes in solar radiation and changes in atmospheric composition due to natural causes (e.g. volcanic eruptions) and human activities (e.g. greenhouse gas emissions and aerosol production). Complicating factors are internal changes in the system, such as quasi-periodic changes in atmosphere, ocean and ice-cover. Some of these interactions are well-understood and can be taken into account as a change in boundary condition such as El Nino – Southern Oscillation. However, to which extent climate change is linked linearly with radiative forcing is a matter of debate: surprises do occur in the climate system as is demonstrated in transition periods from ice-ages to
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