99520 - MODERN CLIMATE CHANGE

Conoscenze e abilità da conseguire

This course will provide students with the scientific foundation of modern, anthropogenic climate change and its impacts. The course will learn (1) the observational evidence of present climate change, (2) fundamental physical processes that shape climate (e.g. solar variability, orbital mechanics, greenhouse gases, the carbon cycle, atmospheric and oceanic circulation, and aerosols), (3) the modern description of climate change (radiative forcing, feedbacks, climate sensitivity) and (4) the physical understanding of predictions of future climate change (for example, how global warming will impact the global water cycle). At the end of the course, students will be able to understand and discuss about material consequences of climate change, like sea level change, variations in precipitation, extreme events and abrupt climate change. This course will also examine the science behind mitigation and adaptation proposals.

Contenuti

Module 1:

Introduction

History of climate change science, the Ozone Hole, Global Warming, The ‘Charney Report’ and the IPCC.

Climate models

Sources of model errors, model hierarchies, model tuning, performance of climate models.

Predictability and Uncertainty

Deterministic, stochastic and chaotic systems, forced and internal variability, predictability of coupled processes, Liouville equation and the ensemble, model error, epistemic, intrinsic and scenario uncertainty. Uncertainty for global change and climate sensitivity, uncertainty for regional climate change, Global warming levels.

Multi-decadal climate projections

Numerical simulations supporting the IPCC, overview of state-of-the-art climate projections, robust and uncertain signals. Analysis of a climate projection. Linking global and regional climate change.

Seasonal-to-decadal climate predictions

Sources of predictability beyond the conventional weather scale. Brief history of Climate predictions. Modern climate predictions, definitions, calibration, verification. Analysis of the forecast of the El Nino Southern Oscillation.

Non-Linear Processes and Tipping Points

Dynamic and thermodynamic changes. Abrupt climate change. Bifurcation theory and noise-induced tipping. Early warning signals.

Climate change in Europe and the Mediterranean

Overview of state-of-the-art climate projections. A guided tour in the IPCC Atlas. Time of emergence of climate change signals.

Climate risk

Climate impact drivers and climate risk. Simple climate risk models. The rationale of adaptation and mitigation.

Module 2:

Introduction: current climate change and earth’s climate history

The instrumental record of temperature. Other evidences of global warming: changes of sea level and cryosphere. Earth’s climate of the past: the paleoclimatological record. Other observed changes of our climate.

Natural and anthropogenic causes of climate change

Possible causes of climate change. Solar luminosity variation. Natural Aerosol. Orbital variations. The greenhouse effect and radiative forcing. Stratospheric cooling. Anthropogenic drivers of climate change. Attribution of modern climate change.

Quantifying temperature changes

Climate sensitivity. Feedbacks. Polar amplification and involved feedbacks.

Clouds and climate

Cloud fundamentals. Cloud microphysics. Cloud feedbacks and climate uncertainty.

Global warming and extremes

Droughts. The response of the hydrological cycle to global warming. Precipitation extremes. Soil moisture. Heat waves. Attribution of climate and weather extreme events.

Sea level

Sea level rise. Global mean sea level changes. Regional sea level changes.

Ocean circulation

The Atlantic Meridional Overturning Circulation (AMOC). The Stommel Model. Multiple equilibria and tipping points. Consequences for AMOC collapse.

Changes in the cryosphere: sea-ice and ice-sheets

Artic sea ice. Processes and feedback. Detection of climate change. Greenland and Antarctica ice sheets.

Testi/Bibliografia

Lecture notes and slides

Nonlinear Climate Dynamics Dijkstra, Henk A. Nonlinear climate dynamics. Cambridge University Press, 2013, (Chapters 1-to-4 and 12).

Predictability of weather and climate, Palmer, Tim, and Renate Hagedorn, eds. Cambridge University Press, 2006, (Chapters 10, 12, 13, 19).

The Climate Demon: Past, Present, and Future of Climate Prediction. Saravanan, Ramalingam. Cambridge University Press, 2021.

The IPCC Assessment reports

Dennis L. Hartmann, Global Physical Climatology

Eli Tziperman, Global Warming Science

J. David Neelin, Climate Change and Climate Modeling

Metodi didattici

Frontal lectures

Modalità di verifica e valutazione dell'apprendimento

The final exam (average duration: 45 minutes) consist of an oral examination to test the student’s level of understanding of the phenomenological, physical and mathematical aspects of the two modules’ contents.

Strumenti a supporto della didattica

PC and projector.

Orario di ricevimento

Consulta il sito web di Paolo Ruggieri

Consulta il sito web di Salvatore Pascale