Some economics of ‘dangerous’ climate change: Reflections on the Stern Review

The Stern Review on the Economics of Climate Change concluded that there can be “no doubt” the economic risks of business-as-usual (BAU) climate change are “very severe” [Stern, 2006. The Economics of Climate Change. HM Treasury, London, p. 188]. The total cost of climate change was estimated to be equivalent to a one-off, permanent 5–20% loss in global mean per-capita consumption today. And the marginal damage cost of a tonne of carbon emitted today was estimated to be around $312 [p. 344]. Both of these estimates are higher than most reported in the previous literature. Subsequently, a number of critiques have appeared, arguing that discounting is the principal explanation for this discrepancy. Discounting is important, but in this paper we emphasise that how one approaches the economics of risk and uncertainty, and how one attempts to model the very closely related issue of low-probability/high-damage scenarios (which we connect to the recent discussion of ‘dangerous’ climate change), can matter just as much. We demonstrate these arguments empirically, using the same models applied in the Stern Review. Together, the issues of risk and uncertainty on the one hand, and ‘dangerous’ climate change on the other, raise very strongly questions about the limits of a welfare-economic approach, where the loss of natural capital might be irreversible and impossible to compensate. Thus we also critically reflect on the state-of-the-art in integrated assessment modelling. There will always be an imperative to carry out integrated assessment modelling, bringing together scientific ‘fact’ and value judgement systematically. But we agree with those cautioning against a literal interpretation of current estimates. Ironically, the Stern Review is one of those voices. A fixation with cost-benefit analysis misses the point that arguments for stabilisation should, and are, built on broader foundations.     

Transient climate changes in a perturbed parameter ensemble of emissions-driven earth system model simulations

We describe results from a 57-member ensemble of transient climate change simulations, featuring simultaneous perturbations to 54 parameters in the atmosphere, ocean, sulphur cycle and terrestrial ecosystem components of an earth system model (ESM). These emissions-driven simulations are compared against the CMIP3 multi-model ensemble of physical climate system models, used extensively to inform previous assessments of regional climate change, and also against emissions-driven simulations from ESMs contributed to the CMIP5 archive. Members of our earth system perturbed parameter ensemble (ESPPE) are competitive with CMIP3 and CMIP5 models in their simulations of historical climate. In particular, they perform reasonably well in comparison with HadGEM2-ES, a more sophisticated and expensive earth system model contributed to CMIP5. The ESPPE therefore provides a computationally cost-effective tool to explore interactions between earth system processes. In response to a non-intervention emissions scenario, the ESPPE simulates distributions of future regional temperature change characterised by wide ranges, and warm shifts, compared to those of CMIP3 models. These differences partly reflect the uncertain influence of global carbon cycle feedbacks in the ESPPE. In addition, the regional effects of interactions between different earth system feedbacks, particularly involving physical and ecosystem processes, shift and widen the ESPPE spread in normalised patterns of surface temperature and precipitation change in many regions. Significant differences from CMIP3 also arise from the use of parametric perturbations (rather than a multimodel ensemble) to represent model uncertainties, and this is also the case when ESPPE results are compared against parallel emissions-driven simulations from CMIP5 ESMs. When driven by an aggressive mitigation scenario, the ESPPE and HadGEM2-ES reveal significant but uncertain impacts in limiting temperature increases during the second half of the twenty-first century. Emissions-driven simulations create scope for development of errors in properties that were previously prescribed in coupled ocean–atmosphere models, such as historical CO₂ concentrations and vegetation distributions. In this context, historical intra-ensemble variations in the airborne fraction of CO₂ emissions, and in summer soil moisture in northern hemisphere continental regions, are shown to be potentially useful constraints, subject to uncertainties in the relevant observations. Our results suggest that future climate-related risks can be assessed more comprehensively by updating projection methodologies to support formal combination of emissions-driven perturbed parameter and multi-model earth system model simulations with suitable observational constraints. This would provide scenarios underpinned by a more complete representation of the chain of uncertainties from anthropogenic emissions to future climate outcomes.     

http://www.sciencedirect.com/science/article/pii/S1674987114001601

Data from a migmatised metapelite raft enclosed within charnockite provide quantitative constraints on the pressure-temperature-time[P-T-t) evolution of the Nagercoil Block at the southernmost tip of peninsular India.An inferred peak metamorphic assemblage of garnet,K-feldspar.sillimanite,plagioclase,magnetite,ilmenite,spinel and melt is consistent with peak metamorphic pressures of 6-8 kbar and temperatures in excess of 900℃.Subsequent growth of cordierite and biotite record high-temperature retrograde decompression to around 5 kbar and 800 C.SHRIMP U-Pb dating of magmatic zircon cores suggests that the sedimentary protoliths were in part derived from felsic igneous rocks with Palaeoproterozoic crystallisation ages.New growth of metamorphic zircon on the rims of detrital grains constrains the onset of melt crystallisation,and the minimum age of the metamorphic peak,to around560 Ma.The data suggest two stages of monazite growth.The first generation of REE-enriched monazite grew during partial melting along the prograde path at around 570 Ma via the incongruent breakdown of apatite.Relatively REE-depleted rims,which have a pronounced negative europium anomaly,grew during melt crystallisation along the retrograde path at around 535 Ma.Our data show the rocks remained at suprasolidus temperatures for at least 35 million years and probably much longer,supporting a long-lived high-grade metamorphic history.The metamorphic conditions,timing and duration of the implied clockwise P-T-t path are similar to that previously established for other regions in peninsular India during the Ediacaran to Cambrian assembly of that part of the Gondwanan supercontinent.     

Variability in Early Amazonian Tharsis stress state based on wrinkle ridges and strike-slip faulting

We present evidence for a decrease in the magnitude of Tharsis-circumferential compressive stress during the Late Hesperian to the Middle Amazonian based on chronologic changes in the predominant style of faulting in southern Amazonis Planitia. Using high-resolution MOLA topography, we identify a population of strike-slip faults that exhibit Middle Amazonian-aged displacements of regional chrono-stratigraphic units. These strike-slip faults are adjacent to an older population of previously documented Late Hesperian-aged thrust faults (wrinkle ridges). Along-strike orientations of these thrust and strike-slip faults reveal the Tharsis-radial stress to be the area's most compressive remote principal stress and that this stress orientation and magnitude persisted throughout the Late Hesperian to the Middle Amazonian. We show that the change in the predominant style of faulting from thrust faulting to strike-slip faulting during this time requires a decrease of the Tharsis-circumferential compressive stress to a magnitude less than lithostatic load, with negligible change in stress orientation.     

Using a fluvial archive to place extreme flood sediment (dis)connectivity dynamics in context of a longer-term record

The aim of this study was to establish the source and provenance of sediments deposited in a large floodplain sink during extreme floods in the Lockyer Creek catchment, Australia, in 2011 and 2013. We place the sediment source patterns in context of the longer-term record to determine whether coarse-grained sediment sources (i.e., very fine sand to very coarse sand) and the spatio-temporal pattern of (dis)connectivity have changed over time. We do this by matching the geochemical properties and age structure of a sediment profile located in a downstream floodplain sink to the elemental composition of source sediments. One hundred and fifty-seven sediment samples from 20 sites across the catchment are analysed using X-ray fluorescence (XRF) spectrometry to compare the elemental ratio composition of the downstream floodplain sink to its source materials. We use Optically Stimulated Luminescence (OSL) dating to determine the age structure of the sediments in the floodplain sink. The northern tributaries and parts of the Lockyer River trunk stream are the primary sources of coarse sediment. These areas are connected (coupled) to the lower trunk stream and floodplain sediment sink. Southern tributaries are largely disconnected (decoupled) and supply little sediment to the floodplain sediment sink. This pattern of sediment source contribution has remained similar over the last 6.8 ka at least. Sediment sources as observed in the 2011 flood have predominated over the mid-late Holocene whilst those in the 2013 flood are rare.     

Late-glacial and Holocene vegetation and climatic history of the Cass Basin, central South Island, New Zealand

Lithology, pollen, macrofossils, and stable carbon isotopes from an intermontane basin bog site in southern New Zealand provide a detailed late-glacial and early Holocene vegetation and climate record. Glacial retreat occurred before 17,000 cal yr B.P., and tundra-like grassland–shrubland occupied the basin shortly after. Between 16,500 and 14,600 cal yr B.P., a minor regional expansion of forest patches occurred in response to warming, but the basin remained in shrubland. Forest retreated between 14,600 and 13,600 cal yr B.P., at about the time of the Antarctic Cold Reversal. At 13,600 cal yr B.P., a steady progression from shrubland to tall podocarp forest began as the climate ameliorated. Tall, temperate podocarp trees replaced stress-tolerant shrubs and trees between 12,800 and 11,300 cal yr B.P., indicating sustained warming during the Younger Dryas Chronozone (YDC). Stable isotopes suggest increasing atmospheric humidity from 11,800 to 9300 cal yr B.P. Mild (annual temperatures at least 1°C higher than present), and moist conditions prevailed from 11,000 to 10,350 cal yr B.P. Cooler, more variable conditions followed, and podocarp forest was completely replaced by montane Nothofagus forest at around 7500 cal yr B.P. with the onset of the modern climate regime. The Cass Basin late-glacial climate record closely matches the Antarctic ice core records and is in approximate antiphase with the North Atlantic.     

Neoliberalism and natural resource management: Agri-environmental standards and the governing of farming practices

Private standards and certification schemes are widely acknowledged as playing an increasingly important role in agri-environmental governance. While much of the existing research concludes that these mechanisms consolidate the global extension of neoliberalism – enhancing the power of corporate actors to the detriment of smaller producers – we argue that this overlooks the complex ways in which standards are used by governments and farmers in the governing of farming practices. Focusing specifically on a process standard – Environmental Management Systems (EMS) – promoted by the Australian government as a way of verifying the ‘clean and green’ status of agricultural exports, we examine how one regional group of producers has sought to use EMS standards in practice. Our analysis of a case study in the state of Victoria appears to confirm that EMS was a successful instrument for the extension of neoliberal governance, reinforcing the production of neoliberal subjectivities and practices amongst farmer participants and enabling the government to compensate for gaps in environmental provision. However, it would be a mistake to interpret the development of this EMS scheme as an example of naïve farmers manipulated by the state. In practice, farmers used the opportunities provided by government funding to undertake actions which expressed their own agri-environmental values and practices. Establishment of an EMS and associated eco-label enabled producers to demonstrate and extend their capacity to act as good environmental stewards. Our research highlights how the local application of environmental standards negotiates and shapes, rather than simply contributes to, neoliberal rule.     

Re-mapping regulatory space: The new governance of Australian dairying

Despite questions currently raised about the future of neoliberalism, it remains embedded within Australian agricultural policy and practice. This paper explores the strengths and limitations of mechanisms contributing to neoliberalism’s survival through a close examination of the restructuring of Australian agricultural production and governance processes under the influence of both globalising impulses and adherence to neoliberal strategies. We trace the changes in governance flowing from the dismantling of regulatory structures in the Australian dairy industry, and the creation of new forms of governance that have both facilitated this transition and dealt with its adverse, often unintended, consequences. The changing governance of Australian dairying is analysed through the lens of three arenas of governance: state, industry and place. Drought has played an important part in re-spacialising dairying and re-shaping the balance between farmers and industry, demonstrating the contingency at play in emerging governance structures. This study of processes of change within the highly export-oriented dairy sector of Australia focuses attention on resistance and on some of the messy actualities of the interplay between state, place and industry - and nature - in neoliberal agri-food governance.