Welcome to the MSc in Earth System ScienceDr Sarah Cornellsarah.email@example.com Lecture slides, notes, and reading material are on Blackboard. Exam past papers and answers will go up soon
This unit: Global Change Science & Policy What is Science? What is Policy? How do they interact? Global Change Science Science policy for global change Sector policy under global change Our Ethos: Interdisciplinarity Debate and discussion Inquiry
How do wedo science? Observation Theoretical Data Analysis Experiment Model Hypothesis
Plots from Steffen et al., IGBP, 2003Step 1: Observation
Intergovernmental Panel on Climate ChangeSummary of main findings (WG II)• Many natural systems are being affected by regional climate changes.• Anthropogenic warming has had a discernible influence on physical and biological systems.• Many other effects are difficult to discern due to adaptation and non-climatic drivers.• Magnitudes of impact can now be estimated more systematically. Natural science• Impacts due to altered frequencies and intensities of climate-related events will change.• Some large-scale climate events may cause very large impacts (especially after C21).• Aggregated and discounted to the present, impacts will impose net annual costs which will Economicsincrease over time as global temperatures increase.• Some adaptation is occurring now, but on a limited basis. /sector policy• Adaptation will be necessary to address already unavoidable impacts• There are barriers, limits and costs to adaptation, but these are not fully understood.• Vulnerability to climate change can be exacerbated by the presence of other stresses.• Future vulnerability depends not only on climate change but also on development pathway.• Sustainable development can reduce vulnerability to climate change, and climate change Vulnerabilitycould impede nations’ abilities to achieve sustainable development pathways.• Many impacts can be avoided, reduced or delayed by mitigation.• A portfolio of adaptation and mitigation measures can diminish the risks associated withclimate change.
Main findings (from executive summary):* Humans have changed ecosystems more rapidly and extensively in the last 50years than in any other period, resulting in a substantial and largely irreversibleloss in diversity of life on Earth, with some 10 to 30 percent of the mammal, birdand amphibian species currently threatened with extinction. * Only four ecosystem services have been enhanced in the last 50 years:increases in crop, livestock and aquaculture production, and increased carbonsequestration for global climate regulation. Two services – capture fisheries andfresh water – are now well beyond levels that can sustain current, much lessfuture, demands. * The degradation of ecosystem services could grow significantly worseduring the first half of this century and is a barrier to achieving the UN MillenniumDevelopment Goals. * The challenge of reversing the degradation of ecosystems while meetingincreasing demands can be met with significant policy and institutional changes.However, these changes will be large and are not currently underway.
Global Environment OutlookA resilience perspective?
Main findings (from summary for decision-makers):There is evidence of unprecedented global change: Global surface warming, air pollution, the ozone hole, land degradation, contamination of freshwater, over-exploited aquatic ecosystems, and declines in species abundance and distribution.These changes are due to human activities in an increasingly globalised,industrialised and interconnected world.Environmental change affects human development options, with poor peoplebeing most vulnerable.Biophysical and social systems can reach tipping points, beyond which thereare abrupt, accelerating or potentially irreversible changes.The transition to sustainability needs to be pursued more intensively:capacity building and technological support.Decision-makers can promote timely action by integrating prevention,adaptation and mitigation efforts into decision-making.Knowledge can be used effectively for the transition to sustainability.
Step 2: Theoretical model? What kind of knowledge do we need to understand the Anthropocene? Chemists, physicists, biologists Observationalists, experimentalists, modellers Natural scientists, social scientists and economists Contemporary, palaeo and ‘possible’ Earth Boffins and policy people
Representing the climate system in models Slide from Brian Hoskins, WCRP
Understanding Ecosystems A unit consisting of a community of organisms and their environment • Niches - place in foodweb and landscape • “Stable” unit with dynamic relationships within community and with surrounding environment
Ecosystems Biome map Plenty of literature on ecosystem modelling by Prentice and co-workers; Dawson and Berry and co-workers
Ecosystem analysisPhysical controls An aside: This kind of science has been built up from building blocks. Contrast with climate science - ‘ﬁrst principles’, deduction Structure Processes Ecosystem functions
A transformative process? “…a dialectical epistemology, which can relinquish the principle of uniformity or determinism, dealing with creativity and the ﬂuidity of social life, without giving up general theories, concepts and causal correlations…” “…a way of knowing the world around us that resolves disagreement through well-reasoned discussion, and is ﬂexibleenough to include multiple viewpoints in that discussion withoutgiving up the credibility of the whole process, because this maybring new insights that make a difference for human society …” My paraphrasing of Domingues, JM (1996) Sociology and the logic of theoretical research. Sociology 30 (4) 763-783
Pressure-State-Response Framework D P S IDriving Forces State Change in Impacts on Pressures in Society Environment Society Agriculture Land and Environmental Industry Physical, Resource Use goods & Energy chemical and services Emissions ecological Transport state Human Technological Services risks Society Households Sector Policy Environmental Statement of Social Policy Objectives Prioritisation Response
Pressure-State-Response Framework D P S I Driving Forces State Change in Impacts on Pressures in Society Environment Society Agriculture Land and Environmental Industry Physical, Resource Use goods & Energy chemical and services Emissions ecological Transport state Human Technological Services risks Society Households Sector Policy Environmental Statement of Social Policy Objectives Prioritisation Mitigation? Adaptation? Reparation? Compensation? Response
Scholze et al., PNAS 2006… or the projected change is not consistent? δT<2°C 2°C<δT<3°C Risk of Change in Freshwater Supply by 2100 δT>3°C
And what do we do about the already committed risk of climate-induced biome shifts?
Step 3: Hypothesis Earth system timelineAges in Ga (109 yr BP)Major transitions in theevolution of life and of the Earth system - often causally connectedT. M. Lenton, H. J. Schellnhuber, E.Szathmary (2004) Nature 431: 913
Costanza et al., (2007) Ambio 36 7 522-527 IHOPE“Understanding the history of how humans have interactedwith the rest of nature can help clarify the options formanaging our increasingly interconnected global system.Simple, deterministic relationships betweenenvironmental stress and social change are inadequate.Extreme drought, for instance, triggered both socialcollapse and ingenious management of waterthrough irrigation. Human responses to change,in turn, feed into climate and ecological systems,producing a complex web of multidirectional connectionsin time and space.Integrated records of the co-evolving human-environment system overmillennia are needed to provide a basis for a deeperunderstanding of the present and for forecasting the future. This requires themajor task of assembling and integrating regional and global historical,archaeological, and paleoenvironmental records.Humans cannot predict the future. But, if we can adequately understand thepast, we can use that understanding to influence our decisions and to create abetter, more sustainable and desirable future.”