Lessons from the past: interpreting the paleorecord & modelling

Transcription

1 Agenda ATLAB WP5 Workshop - June 11-13, 2014 Lessons from the past: interpreting the paleorecord & modelling ING PAN, Research Centre in Kraków 1. DAY - Wednesday General introduction into paleoclimate dynamics In attempting to account for long-term paleoclimatic variations, we are led to broaden our view of the climate system and to restructure our approach to a more complete theory of climate. We begin by describing the external forcing of the climate system and the observed response, as represented by proxy evidence for paleoclimatic variations. One focus of the course is to identify driving mechanisms for climate change. This is done through numerical models of the Earth system and statistical analysis of instrumental and proxy data. It is of vital importance to understand whether increasing human population and industrialization have already caused, or have the potential to induce significant changes in Earth's climate. In order to properly address this question, one needs quantitative information regarding the amplitude and rapidity of natural variations of temperature in the ocean, over the continents, and in the cryosphere. The best way to ascertain the extent of past changes is through the inspection of historical time series of direct temperature measurements or documentation of such environmental observations. Unfortunately, the type of direct temperature measurement records which would allow one to quantify climate changes on a global scale are too short, and they fall already within the period of strong human impact on natural conditions. Information regarding the pre-anthropogenic state of the system can be obtained either from proxies that record past climate and environmental conditions, or by simulating climate using comprehensive models of the climate system under appropriate external forcing changes. The paleoclimate record provides an excellent test of these models as it reveals climate variations that have actually occurred in the past. Special areas: feedback mechanisms in the climate system; the role of the global oceanic thermohaline circulation for paleo and recent climate variations; deglaciation; Holocene climate; Glacial climate; Climate modes like ENSO and NAO; Milankovitch theory of the ice ages Registration + coffee/tea :10 - Opening Ceremony Marek Lewandowski/Gerrit Lohmann/Jarosław Tyszka :15 - lecture - Szymon P. Malinowski: Changing climate - physicist's perspective 11:15-12:15 - lecture - Gerrit Lohmann: General approaches to paleoclimates

2 12:15-12:30 coffee/tea 12:30-13:30 lecture - Paul Markwick: General approaches to paleoclimates Objectives: to provide an overview of how palaeoclimatology and Earth System Modelling is applied Applications in exploration and climate change Geological climate proxies and climate space 13:30-15:00 lunch break 15:00-16:00 lecture - Gerrit Lohmann: Holocene and Interglacial dynamics 16:00-16:15 coffee/tea 16:15-17:30 exercises - Climate Model: Ocean box model; Statistical data analysis (Lohmann, Knorr) For the exercises: Bring your laptop with you

3 2. DAY - Thursday Cenozoic climate The lectures are based on the foundations of different quantitative approaches of understanding the climate system on tectonic time-scales, with a special emphasis on comprehensive modelling approaches. The lectures will be complemented by case studies of current research examples. We will study the behaviour of the climate system during the transition from a greenhouse world to an icehouse world and it s impact on paleoenviroment. The changes during a transition are of fundematal interest for society because we will soon face (or even we are now facing) a transition of a climate from ice-house to a hot-house world as a result of the antrophogenic impact on climate. The size and extent of environmental changes are still under debate however there are no doubts that many changes (not only greater temperature but also i.e. desertification and greater flooding, ocean acidification) will happen. Beside that we will also study the importance of paleotectonics and paleogeography in climate modelling. To run the computer simulations one needs topography, bathymetry, vegetation (if we don t have dynamic vegatation module in our modelling software), trace gases concentration and orbital parameters, plus solar constant. For initialization we can set arbitrary temperature, salinity and other climatic parameters. All of them in equilibrium state should be dependend only on the first group of data. This shows the importance of accuracy of proxy data interpretations as well as geophysical resesarch for climate modeller. It is especially difficult to asses precisely paleobathymetry. Oceanic crust is constantly being produced as well as subducted. The oldest ocean crust is less than 200 millions years old. The average age is much lower. There are large areas in the ocean where the crust is younger than 50 millions years. There are algorithms which asses depth of the ocean based on ocean crust age. Similar situation we encounter with orography. It is very important to know where the mountain ranges where situated as well as the height of those mountains. Since some of the mountain ranges does not exist any longer we must obtain knowledge about them from other geological record. For climate simulations it is necessary also to have hydrological discharge component. For that we must reconstruct river runoffs using appropriate algorithms. 09:00-11:00 lecture - Paul Markwick Cenozoic Climate Evolution An overview of the geological evidence of Cenozoic change: the hot-house - ice-house transition Earth System Model evidence for climate change Testing Models The evidence for major glaciation in a non-glacial world 11:00-11:30 coffee/tea 11:30-13:00 lecture - Gregor Knorr: Modeling and analyzing Miocene climate changes Relative importance of vegetation, tectonic setting and CO2 as forcing factors The middle Miocene climate transition at about 14 million years ago 13:00-15:00 lunch break

4 15:00-16:30 exercises and lecture - Paul Markwick Defining Earth System Model Boundary Conditions Palaeogeography Methods Palaeoelevation and drainage Exercise: reconstructing river systems for Earth System Models For the exercises: Bring your laptop with you

5 3. DAY - Friday Abrupt climate change Milankovitch theory (1941) gained the status of a paradigm for explaining the Pleistocene ice-ages. A key element of this theory is that summer insolation at high latitudes of the northern hemisphere determines glacial/interglacial transitions connected with the waxing and waning of large continental ice sheets (e.g. Imbrie and Imbrie, 1980). In the last two million years, the glacial-interglacial cycles provide the dominant signal in the climate record. Climate conditions of glacials and interglacials are very different. During the Last Glacial Maximum, about 20,000 years before present, surface temperature in the north Atlantic realm was significant lower than today. Although there are indications for Milankovitsch's astronomical theory (Hays et al., 1976), the driving mechanism of the northern hemisphere is under debate. Examples of open questions related to Milankowitch theory are: Why are the 41,000 and the 100,000 years cycles so dominant in the ice volume changes? Why did a shift from a 41,000 to a 100,000 cycle occur at 1 million years before present? The reason for the dominance of year cycle, 100,000 cycle (until 0.9 Mio years B.P.) and the years cycle (since react in a 0.9 Mio years B.P.) are not well understood, yet! The first part of the lectures will be focused on the rapid climate change. From the proxy data we can learn that both in the deep past (PETM) and in the Quarternary (D O events) happened very abrupt climate changes where average temperatur raised/dropped in a relatively short period. Those transitions are especially interesting as analogues for unusually fast climate changes happening now. By investigating phenomena during PETM we can predict phenomena which might happen on Earth. 09:00-10:00 lecture - Gregor Knorr: Abrupt climate change and glacial terminations Millennial time-scale variability during ice ages Abrupt climate changes in models of different complexity 10:00-11:00 lecture - Paul Markwick: The importance of scale in understanding palaeoclimate change Defining the temporal and spatial resolution of palaeoclimatology in the Geological Record Rapid climate changes in deep time - how are these defined? PETM, Anoxic Events. What does this mean for using geological palaeoclimatology in looking at future climate change? 11:00-11:30 coffee/tea 11:30-12:30 lecture - Gerrit Lohmann: Terminations and Astronomical Theory 12:30-13:00 open discussion

6 13:00-15:00 lunch (catering) 15:00-16:00 exercises - Gerrit Lohmann: Orbital parameters and insolation 16:00 Closing words 16:15-17:00 coffee/tea For the exercises: Bring your laptop with you Further Literature: Saltzman, B., Dynamical Paleoclimatology - a generalized theory of global climate change, Academic Press, San Diego, 2002, 345 pp. Earth's Climate Past and Future < by William F. Ruddiman Jansen, E., et al, 2007: Palaeoclimate. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the IPCC. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. s/modelling/lessons/goeteborg/ar4-wg1-chapter6.pdf