The threat to climate change mitigation posed by the abundance of fossil fuels

This article analyses the trends in primary demand for fossil fuels and renewables, comparing regions with large and small domestic fossil fuel reserves. We focus on countries that hold 80% of global fossil fuel reserves and compare them with key countries that have meagre fossil fuel reserves. We show that those countries with large domestic fossil fuel reserves have experienced a large increase in primary energy demand from fossil fuels, but only a moderate or no increase in primary energy from renewables, and in particular from non-hydro renewable energy sources (NHRES), which are assumed to represent the cornerstone of the future transformation of the global energy system. This implies a tremendous threat to climate change mitigation, with only two principal mitigation options for fossil-fuel-rich economies if there is to be compliance with the temperature goals of the Paris Agreement: (1) leave the fossil fuels in the ground; and (2) apply carbon capture and storage (CCS) technologies. Combinations of these two options to exploit their respective possibilities synergistically will require strong initiatives and incentives to transform a certain amount of the domestic fossil fuel reserves (including the associated infrastructure) into stranded assets and to create an extensive CCS infrastructure. Our conclusion is that immediate and disruptive changes to the use of fossil fuels and investments in non-carbon-emitting technologies are required if global warming is to be limited to well below 2°C. Collective actions along value chains in business to divert from fossil fuels may be a feasible strategy.

Key policy insights

• The main obstacle to compliance with any reasonable warming target is the abundance of fossil fuels, which has maintained and increased momentum towards new fossil-fuelled processes.

• So far, there has been no increase in the share of NHRES in total global primary energy demand, with a clear decline in the NHRES share in India and China.

• There is an immediate need for the global community to develop fossil fuel strategies and policies.

• Policies must account for the global trade flow of products that typically occurs from the newly industrialized fossil fuel-rich countries to the developed countries.

     

Uncertainty and assessment of the issues posed by urgent climate change. An editorial comment

Climate change raises a number of difficult issues concerning the management of scientific uncertainty. Urgent decisions seem to call for quantified probability statements as the basis of rational policy-making. Yet the answers to many important questions such as the likely rate of sea level rise are not easily quantified, and the utilization of any estimates based on ‘collective subjective probability’ necessarily depends on value-laden judgments about burden-of-proof and the distribution of risk. We suggest that there is a need for a new form of risk assessment that is based in, but not limited to, the scientific community, in which rapid but credible processes address the critical questions that we are now facing.     

Vegetation and climate variability: a GCM modelling study

Vegetation is known to interact with the other components of the climate system over a wide range of timescales. Some of these interactions are now being taken into account in models for climate prediction. This study is an attempt to describe and quantify the climate–vegetation coupling at the interannual timescale, simulated with a General Circulation Model (HadSM3) coupled to a dynamic global vegetation model (TRIFFID). Vegetation variability is generally strongest in semi-arid areas, where it is driven by precipitation variability. The impact of vegetation variability on climate is analysed by using multivariate regressions of boundary layer fluxes and properties, with respect to soil moisture and vegetation fraction. Dynamic vegetation is found to significantly increase the variance in the surface sensible and latent heat fluxes. Vegetation growth always causes evapotranspiration to increase, but its impact on sensible heat is less straightforward. The feedback of vegetation on sensible heat is positive in Australia, but negative in the Sahel and in India. The sign of the feedback depends on the competing influences, at the gridpoint scale, of the turbulent heat exchange coefficient and the surface (stomatal) water conductance, which both increase with vegetation growth. The impact of vegetation variability on boundary layer potential temperature and relative humidity are shown to be small, implying that precipitation persistence is not strongly modified by vegetation dynamics in this model. We discuss how these model results may improve our knowledge of vegetation–atmosphere interactions and help us to target future model developments.     

A study of climate and weather variability over the tropical southwest Indian Ocean

Summary The climatology and variability of summer convection and circulation over the tropical southwest Indian Ocean is investigated using satellite imagery, routine synoptic observations, outgoing longwave radiation (OLR) data, sea surface temperatures (SST) and areal averaged rainfall departures. OLR has a –0.90 correlation with rainfall departures and the OLR minimum (ITCZ) in January and February lies across the 10°S latitude, extending further south near Madagascar. The intensity of ITCZ convection is greatest in the longitudes 20–35°E over northern Zambia and is considerably reduced over the SW Indian Ocean. Spatial correlations are analyzed for standardized departures of OLR, rainfall and SST. The correlations change sign in a coherent fashion, creating a climatic dipole between southern Africa and the SW Indian Ocean. Interannual trends are examined through analysis of January–February zonal and meridional wind indices constructed from significantly correlated variables at Zimbabwe, Madagascar and Mauritius. Circulation variability is dominated by quasi-decadal cycles and a trend of inereasing westerly winds. Zonal wind shear alternates from easterly (barotropic) to westerly and together with SST appears to regulate the frequency and intensity of tropical cyclogenesis. Areally averaged rainfall departures exhibit 6.25 year cycles in NE Madagascar and 12.5 and 18.75 year cycles in SW Madagascar and Zimbabwe, respectively. Summer rainfall and meridional winds in NE Madagascar and Zimbabwe are out of phase and negatively correlated in most summers. The presence of synoptic weather systems is assessed using daily Hovmoller-type satellite imagery composites. Convective structure is dominated by transient waves in the 10°–20°S latitude band, with periods of 15–20 days common. The waves are more prominent in summers with increased easterly shear and contribute to fluctuations in rainfall over SE Africa.With 8 Figures     

Comparative analysis of geo-engineering approaches to climate stabilization

Geo-engineering approaches to modern climate stabilization, irrelative to the Kyoto Protocol measures, are under consideration. Conditionally, these approaches are subdivided into two groups: purposive changes in the Earth radiation balance to compensate the greenhouse gas effect and removal of the excessive amount of carbon dioxide from the atmosphere. The first group includes such methods as injection of sulfate and other reflecting aerosols into the stratosphere, creation of orbital reflectors or reflectors at the Lagrange point, an increase in cloudiness over the World Ocean, and a change in the Earth surface albedo. Increased carbon dioxide uptake by forests, ocean, and artificial absorbers are considered within the second group. The methods considered were subject to a comparative analysis using the following criteria: possible fast realization, the ability to counteract the doubling of greenhouse gases, availability of natural analogs, impact on geophysical systems within natural variations, the absence of unacceptable ecological implications, possibility, if necessary, to immediately halt the action. The comparison showed that the use of stratospheric sulfate aerosols can be the most effective. It is emphasized that all geo-engineering directions can be realized simultaneously with the measures stipulated by the Kyoto Protocol.     

Intraseasonal and interannual climate variability

Major advances in our understanding of intraseasonal-interannual climate variability during the past three decades are reviewed. Prospects for prediction on these time-scales are briefly discussed.Paper based on talk presented at the session honoring J. Murray Mitchell at the December 1986 AGU meeting in San Francisco, CA.     

Tropical deforestation and climate variability

A new tropical deforestation experiment has been performed, with the ARPEGE-Climat atmospheric global circulation model associated with the ISBA land surface scheme. Simulations are forced with observed monthly mean sea surface temperatures and thus inter-annual variability of the ocean system is taken into account. The local mean response to deforestation over Amazonia and Africa is relatively weak compared with most published studies and compensation effects are particularly important. However, a large increase in daily maximum temperatures is obtained during the dry season when soil water stress dominates. The analysis of daily variability shows that the distributions of daily minimum and maximum temperatures are noticeably modified with an increase in extreme temperatures. Daily precipitation amounts also indicate a weakening of the convective activity. Conditions for the onset of convection are less frequently gathered, particularly over southern Amazonia and western equatorial Africa. At the same time, the intensity of convective events is reduced, especially over equatorial deforested regions. The inter-annual variability is also enhanced. For instance, El Niño events generally induce a large drying over northern Amazonia, which is well reproduced in the control simulation. In the deforested experiment, a positive feedback effect leads to a strong intensification of this drying and a subsequent increase in surface temperature. The change in variability as a response to deforestation can be more crucial than the change of the mean climate since more intense extremes could be more detrimental for agriculture than an increase in mean temperatures.     

The reluctance of resource-users to adopt seasonal climate forecasts to enhance resilience to climate variability on the rangelands

As the impacts of climate-change on resource-dependent industries manifest, there is a commensurate effort to identify and implement strategies to reduce them. Yet, even when useful knowledge and tools exist, there can be poor adoption of adaptation strategies. We examine the reasons behind sub-optimal adoption of seasonal climate forecasts by graziers for managing climate variability. We surveyed 100 graziers in north-east Queensland, Australia and examined the influence of adaptive capacity, resource-dependency and forecast-perception on uptake. Technical perceptions were not important. Strategic skills, environmental awareness and social capital were. Results suggest that social factors (but not technical factors) are significant. These insights are important for adaptation planning and for maximising the resilience of communities and industries dependent on climate-sensitive resources.     

Divergent adaptation to climate variability: A case study of pastoral and agricultural societies in Niger

Adaptation is a complex, dynamic, and sometimes unequal process. Stemming from social ecological systems theories of climate change adaptation and adaptive capacity, this case study introduces the concept of ‘divergent’ adaptation. Adaptation is divergent when one user or group's adaptation causes a subsequent reduction in another user or group's adaptive capacity in the same ecosystem. Using the example of pastoral and agricultural groups in northern and southern rainfall zones of Niger, this study illustrates the concept of divergent adaptation by identifying changes to the adaptive capacity of users who are currently engaged in conflicts over access to natural resources. Similar to other studies, we find that expansion of farmland and the consequent loss of pastoral space are restricting pastoral adaptation. Divergent adaptations favoring agricultural livelihoods include cultivating near or around pastoral wells or within pastoral corridors, both of which limit the mobility and entitlements of pastoralists. Institutions rarely secure pastoral routes and access to water points, a problem that is compounded by conflicting modes of governance, low accountability, and corruption. The case study illustrates the need to enhance the adaptive capacity of multiple user groups to reduce conflict, enhance human security, and promote overall resilience.     

Operationalizing longitudinal approaches to climate change vulnerability assessment

The past decade has seen a proliferation of community-scale climate change vulnerability assessments globally. Much of this work has employed frameworks informed by scholarship in the vulnerability field, which draws upon interviews with community members to identify and characterize climatic risks and adaptive responses. This scholarship has developed a baseline understanding of vulnerability in specific places and industries at particular times. However, given the dynamic nature of vulnerability new methodologies are needed to generate insights on how climate change is experienced and responded to over time. Longitudinal approaches have long been used in sociology and the health sciences to capture the dynamism of human processes, but their penetration into vulnerability research has been limited. In this article, we describe the application of two longitudinal approaches, cohort and trend studies, in climate change vulnerability assessment by analyzing three case studies from the Arctic where the authors applied these approaches. These case studies highlight how longitudinal approaches can be operationalized to capture the dynamism of vulnerability by identifying climate anomalies and trends, and how adaptations develop over time, including insights on themes such as social learning and adaptive pathways.     

Response of the mean global vegetation distribution to interannual climate variability

The impact of interannual variability in temperature and precipitation on global terrestrial ecosystems is investigated using a dynamic global vegetation model driven by gridded climate observations for the twentieth century. Contrasting simulations are driven either by repeated mean climatology or raw climate data with interannual variability included. Interannual climate variability reduces net global vegetation cover, particularly over semi-arid regions, and favors the expansion of grass cover at the expense of tree cover, due to differences in growth rates, fire impacts, and interception. The area burnt by global fires is substantially enhanced by interannual precipitation variability. The current position of the central United States’ ecotone, with forests to the east and grasslands to the west, is largely attributed to climate variability. Among woody vegetation, climate variability supports expanded deciduous forest growth and diminished evergreen forest growth, due to difference in bioclimatic limits, leaf longevity, interception rates, and rooting depth. These results offer insight into future ecosystem distributions since climate models generally predict an increase in climate variability and extremes. CCR Contribution # 941     

Arctic radiation deficit and climate variability

One of the generally accepted climatic effects of stratospheric aerosol injection is the reduction of the global radiation in high latitudes by an order of 5% during El Chichon type eruptions. To test the effect of a high-latitude radiation deficit on global climate, a GCM experiment was performed with the ECMWF T21 atmosphere general circulation model (AGCM). The results provide physically-consistent evidence that this radiation deficit is a possible external forcing factor for severe climatic anomalies not only in the area directly affected by the reduced radiation, but also in the tropics. The most important factor is the creation of enhanced snow cover in regions of Asia that are distant from the location of the introduced radiation anomaly. The simulated results show certain features that are well known from observations in weak monsoon years, i.e. the weakened easterly jet in the upper troposphere over northern India, prolonged winter monsoon conditions, and prevailing anticyclonic vorticity anomalies over the entire Indian summer monsoon region. Over the western Pacific at the end of boreal winter (May), increased convective activity leads to a negative Walker circulation anomaly with westerly wind anomalies near the surface and easterly anomalies in the upper troposphere. This is known as one of the most important anomalies at the beginning of an El Niño/Southern Oscillation (ENSO) event.This paper was presented at the International Conference on Modelling of Global Climate Change and Variability, held in Hamburg 11–15 September 1989 under the auspices of the Meteorological Institute of the University of Hamburg and the Max Planck Institute for Meteorology. Guest Editor for these papers is Dr. L. Dümenil     

Interannual variability and regional climate simulations

Summary An assessment is made of a regional climate model's skill in simulating the mean climatology and the interannual variability experienced in a specific region. To this end two ensembles comprising three realizations of month-long January and July simulations are undertaken with a limited are a operational NWP model. The modelling suite is driven at its lateral boundaries by analysed meteorological fields and the computational domain covers Europe and the North-western Atlantic with a horizontal resolution of 56 km.Validation is performed against both operational ECMWF analyses and objectively analysed precipitation fields from a network of ~ 1400 SYNOP rain gauge stations. Analysis of the simulated ensemble-mean climatology indicates that the model successfully reproduces both the winter and summer distributions of the primary dynamical and thermodynamical field, and also provides a reasonable representation of the measured precipitation over most of Europe. Typically the domain averaged model-biases are below 0.5 K for temperature and 0.1 g/kg for specific humidity. Analysis of the interannual variability reveals that the model captures the wintertime changes including that of the precipitation distribution, but in contrast the summertime precipitation totals for the individual years is not simulated satisfactorily and only partially reproduces the observed regional interannual variability.The latter shortcomings are related to the following factors. Firstly the model bias in the dynamical fields is somewhat larger for summer than winter, while at the same time summertime interannual variability is associated with weaker effects in the dynamical fields. Secondly the summertime precipitation distribution is more substantially affected by small-scale moist convection and surface hydrological processes. Together these two factors suggest that summertime precipitation over continental extratropical land masses might be intrinsically less predictable than wintertime synoptic scale precipitation.With 17 Figures     

Interannual variability of Mediterranean evaporation and its relation to regional climate

Gridded monthly evaporation data for 1958–2006 from the Woods Hole Oceanographic Institution data set are used to investigate interannual variability of Mediterranean evaporation during cold and hot seasons and its relation to regional atmospheric dynamics, sea surface temperature and atmospheric elements of the hydrological cycle. The first EOF mode of Mediterranean evaporation, explaining more than 50% of its total variance, is characterized by the monopole pattern both in winter and summer. However, despite structural similarity, the EOF-1 of Mediterranean evaporation is affected by different climate signals in cold and hot seasons. During winter the EOF-1 is associated with the East Atlantic teleconnection pattern. In summer, there is indication of tropical influence on the EOF-1 of Mediterranean evaporation (presumably from Asian monsoon). Both in winter and summer, principal components of EOF-1 demonstrate clear interdecadal signals (with a stronger signature in summer) associated with large sea surface temperature anomalies. The results of a sensitivity analysis suggest that in winter both the meridional wind and the vertical gradient of saturation specific humidity (GSSH) near the sea surface contribute to the interdecadal evaporation signal. In summer, however, it is likely that the signal is more related to GSSH. Our analysis did not reveal significant links between the Mediterranean evaporation and the North Atlantic Oscillation in any season. The EOF-2 of evaporation accounts for 20% (11%) of its total variance in winter (in summer). Both in winter and summer the EOF-2 is characterized by a zonal dipole with opposite variations of evaporation in western and eastern parts of the Mediterranean Sea. This mode is associated presumably with smaller scale (i.e., local) effects of atmospheric dynamics. Seasonality of the leading modes of the Mediterranean evaporation is also clearly seen in the character of their links to atmospheric elements of the regional hydrological cycle. In particular, significant links to precipitation in some regions have been found in winter, but not in summer.     

Reconciling approaches to climate change adaptation for Colombian agriculture

The projected impact of climate change on agro-ecological systems is considered widespread and significant, particularly across the global tropics. As in many other countries, adaptation to climate change is likely to be an important challenge for Colombian agricultural systems. In a recent study, a national-level assessment of the likely future impacts of climate change on agriculture was performed (Ramirez-Villegas et al. Clim Chang 115:611–628, 2012, RV2012). The study diagnosed key challenges directly affecting major crops and regions within the Colombian agricultural system and suggested a number of actions thought to facilitate adaptation, while refraining from proposing specific strategies at local scales. Further insights on the study were published by Feola (2013) (F2013), who stressed the need for transformative adaptation processes to reduce vulnerability particularly of resource-limited farmers, and the benefits of a predominantly stakeholder-led approach to adaptation. We clarify that the recommendations outlined in RV2012 were not intended as a recipe for multi-scale adaptation, but rather a set of actions that are required to diagnose and develop adaptation actions particularly at governmental levels in coordination with national and international adaptation initiatives. Such adaptation actions ought to be, ideally, a product of inclusive sub-sectorial assessments, which can take different forms. We argue that Colombian agriculture as a whole would benefit from a better outlining of adaptation needs across temporal scales in sub-sectorial assessments that take into account both RV2012 and F2013 orientations to adaptation. We conclude with two case studies of research on climate change impacts and adaptation developed in Colombia that serve as examples of realistic, productive sectorial and sub-national assessments.