Wake Response to an Ocean-Feedback Mechanism: Madeira Island Case Study

We focus on an island wake episode that occurred in the Madeira Archipelago region of the north-east Atlantic at $32.5^{\circ }\mathrm{N}, 17^{\circ }\mathrm{W}$ . The Weather Research and Forecasting numerical model was used in a (one-way) downscaling mode, considering initial and boundary conditions from the European Centre for Medium-range Weather Forecasts system. The current literature emphasizes adiabatic effects on the dynamical aspects of atmospheric wakes. Changes in mountain height and consequently its relation to the atmospheric inversion layer should explain the shift in wake regimes, from a ‘strong-wake’ to ‘weak-wake’ scenario. Nevertheless, changes in sea-surface temperature variability in the lee of an island can induce similar regime shifts because of exposure to stronger solar radiation. Increase in evaporation contributes to the enhancement of convection and thus to the uplift of the stratified atmospheric layer above the critical height, with subsequent internal gravity wave activity.     

The challenge to detect and attribute effects of climate change on human and natural systems

Future scenarios of the energy system under greenhouse gas emission constraints depict dramatic growth in a range of energy technologies. Technological growth dynamics observed historically provide a useful comparator for these future trajectories. We find that historical time series data reveal a consistent relationship between how much a technology’s cumulative installed capacity grows, and how long this growth takes. This relationship between extent (how much) and duration (for how long) is consistent across both energy supply and end-use technologies, and both established and emerging technologies. We then develop and test an approach for using this historical relationship to assess technological trajectories in future scenarios. Our approach for “learning from the past” contributes to the assessment and verification of integrated assessment and energy-economic models used to generate quantitative scenarios. Using data on power generation technologies from two such models, we also find a consistent extent - duration relationship across both technologies and scenarios. This relationship describes future low carbon technological growth in the power sector which appears to be conservative relative to what has been evidenced historically. Specifically, future extents of capacity growth are comparatively low given the lengthy time duration of that growth. We treat this finding with caution due to the low number of data points. Yet it remains counter-intuitive given the extremely rapid growth rates of certain low carbon technologies under stringent emission constraints. We explore possible reasons for the apparent scenario conservatism, and find parametric or structural conservatism in the underlying models to be one possible explanation.     

Climate change and infectious diseases: Can we meet the needs for better prediction?

The next generation of climate-driven, disease prediction models will most likely require a mechanistically based, dynamical framework that parameterizes key processes at a variety of locations. Over the next two decades, consensus climate predictions make it possible to produce forecasts for a number of important infectious diseases that are largely independent of the uncertainty of longer-term emissions scenarios. In particular, the role of climate in the modulation of seasonal disease transmission needs to be unravelled from the complex dynamics resulting from the interaction of transmission with herd immunity and intervention measures that depend upon previous burdens of infection. Progress is also needed to solve the mismatch between climate projections and disease projections at the scale of public health interventions. In the time horizon of seasons to years, early warning systems should benefit from current developments on multi-model ensemble climate prediction systems, particularly in areas where high skill levels of climate models coincide with regions where large epidemics take place. A better understanding of the role of climate extremes on infectious diseases is urgently needed.     

Impact of climate change on the hydrogeology of two basins in northern France

This study presents an analysis of climate-change impacts on the water resources of two basins located in northern France, by integrating four sources of uncertainty: climate modelling, hydrological modelling, downscaling methods, and emission scenarios. The analysis focused on the evolution of the water budget, the river discharges and piezometric heads. Seven hydrological models were used, from lumped rainfall-discharge to distributed hydrogeological models, and led to quite different estimates of the water-balance components. One of the hydrological models, CLSM, was found to be unable to simulate the increased water stress and was, thus, considered as an outlier even though it gave fair results for the present day compared to observations. Although there were large differences in the results between the models, there was a marked tendency towards a decrease of the water resource in the rivers and aquifers (on average in 2050 about ?14 % and ?2.5 m, respectively), associated with global warming and a reduction in annual precipitation (on average in 2050 +2.1 K and ?3 %, respectively). The uncertainty associated to climate models was shown to clearly dominate, while the three others were about the same order of magnitude and 3–4 times lower. In terms of impact, the results found in this work are rather different from those obtained in a previous study, even though two of the hydrological models and one of the climate models were used in both studies. This emphasizes the need for a survey of the climatic-change impact on the water resource.     

Reflections on the current state of global climate response

What is the significance of the 2007 United Nations Climate Change Conference in Bali? The formal outcomes, especially the ‘Bali Action Plan’, are described and commented on, along with the challenges for negotiating a post-2012 agreement in Copenhagen during 2008 and 2009. The article concludes that the outcome of the Bali meeting is insufficient when compared to the nature of the challenge posed by climate change. However, it can nevertheless be considered a success in terms of ‘Realpolitik’ in paving the way for the negotiations ahead, because some real changes have been discerned in the political landscape. The challenges for the road towards Copenhagen are manifold: the sheer volume and complexity of the issues and the far-reaching nature of decisions such as differentiation between non- Annex I countries pose significant challenges in themselves, while the dependency on the electoral process in the USA introduces a high element of risk into the whole process. The emergence of social justice as an issue turns climate policy into an endeavour to improve the world at large—thereby adding to the complexity. And, finally, the biggest challenge is the recognition that the climate problem requires a global solution, that Annex I and non-Annex I countries are mutually dependent on each other and that only cooperation regarding technology in combination with significant financial support will provide the chance to successfully tackle climate change.     

Cross-national patterns of governance mechanisms in nationally determined contributions (NDCs) under the Paris Agreement

ABSTRACT

The continuous submission and scaling-up of Nationally Determined Contributions (NDCs) constitutes a key feature of the Paris Agreement. In their NDCs, states propose governance mechanisms for implementation of climate action, in turn distinguishing appropriate roles for the state in climate governance. Clarity on Parties’ suggested roles for the state makes explicit assumptions on the premise of climate policy, in turn contributing to enhanced transparency in negotiations on the scaling-up of NDCs. This also speaks to ongoing debates on roles for the state in climate governance literature. This article identifies the governance mechanisms proposed by states in their NDCs and the roles for the state envisioned by those governance mechanisms, and also examines how cross-national patterns of roles for the state break or converge with conventional patterns of international politics. The analysis shows that states propose a plurality of roles, which to different extents may be complementary or conflictual. We conclude that income, region, and the Annexes under the United Nations Framework Convention on Climate Change (UNFCCC) are important for understanding suggested roles for the state, but that there are nuances to be further explored. We argue that this paper has three key findings: i) a majority of states rely on market mechanisms to implement their NDCs while rules on implementation and assessment of market mechanisms are still an outstanding issue in the negotiations, meaning that resolving this issue will be essential; ii) the process for evaluating and assessing qualitative governance mechanisms needs to be specified; and iii) increased awareness of differing views on the state’s roles makes explicit different perspectives on what constitutes an ambitious and legitimate contribution to combating climate change.

Key policy insights

• A majority of states (> 75%) envision the state as regulator (creating and strengthening legislation), market facilitator (creating and maintaining market structures), or facilitator (creating more favourable material conditions for climate-friendly behaviour).

• Greater awareness of differing views on roles for the state can increase understanding of different perspectives on ambition and legitimacy of contributions, in turn facilitating trust in negotiations.

• A distinction between substantive and procedural qualitative governance mechanisms and their function and interaction would facilitate the stocktaking dialogues.

     

Solar-Cycle Variation of Subsurface Zonal Flow

We study the solar-cycle variation of the zonal flow in the near-surface layers of the solar convection zone from the surface to a depth of 16 Mm covering the period from mid-2001 to mid-2013 or from the maximum of Cycle 23 through the rising phase of Cycle 24. We have analyzed Global Oscillation Network Group (GONG) and Helioseismic and Magnetic Imager (HMI) Dopplergrams with a ring-diagram analysis. The zonal flow varies with the solar cycle showing bands of faster-than-average flows equatorward of the mean latitude of activity and slower-than-average flows on the poleward side. The fast band of the zonal flow and the magnetic activity appear first in the northern hemisphere during the beginning of Cycle 24. The bands of fast zonal flow appear at mid-latitudes about three years in the southern and four years in the northern hemisphere before magnetic activity of Cycle 24 is present. This implies that the flow pattern is a direct precursor of magnetic activity. The solar-cycle variation of the zonal flow also has a poleward branch, which is visible as bands of faster-than-average zonal flow near 50° latitude. This band appears first in the southern hemisphere during the rising phase of the Cycle 24 and migrates slowly poleward. These results are in good agreement with corresponding results from global helioseismology.     

On Dynamics of G-Band Bright Points

Various parameters describing the dynamics of G-band bright points (GBPs) were derived from G-band images, acquired by the Dutch Open Telescope (DOT), of a quiet region close to the disk center. Our study is based on four commonly used diagnostics (effective velocity, change in the effective velocity, change in the direction angle, and centrifugal acceleration) and two new ones (rate of motion and time lag between recurrence of GBPs). The results concerning the commonly used parameters are in agreement with previous studies for a comparable spatial and temporal resolution of the used data. The most probable value of the effective velocity is ～?0.9 km?s^?1, whereas we found a deviation of the effective velocity distribution from the expected Rayleigh function for velocities in the range from 2 to 4 km?s^?1. The change in the effective velocity distribution is consistent with a Gaussian one with FWHM=0.079 km?s^?2. The distribution of the centrifugal acceleration exhibits a highly exponential nature (a symmetric Gaussian centered at the zero value). To broaden our understanding of the dynamics of GBPs, two new parameters were defined: the real displacement between their appearance and disappearance (rate of motion) and the frequency of their recurrence at the same locations (time lag). For ～?45 % of the tracked GBPs, their displacement was found to be small compared to their size (the rate of motion smaller than one). The locations of the tracked GBPs mainly cover the boundaries of supergranules representing the network, and there is no significant difference in the locations of GBPs with small (m<1) and large (m>2) values of the rate of motion. We observed a difference in the overall trend of the obtained distribution for the values of the time lag smaller (slope of the trend line being ?0.14) and greater (?0.03) than ～?7 min. The time lags mostly lie within the interval of ～?2?–?3 min, with those up to ～?4 min being more abundant than longer ones. Results for both new parameters indicate that the locations of different dynamical types of GBPs (stable/farther traveling or with short/long lifetimes) are bound to the locations of more stable and long-living magnetic field concentrations. Thus, the disappearance/reappearance of the tracked GBPs cannot be perceived as the disappearance/reappearance of their corresponding magnetic field concentrations.     

Migration and Extension of Solar Active Longitudinal Zones

Solar active longitudes show a characteristic migration pattern in the Carrington coordinate system if they can be identified at all. By following this migration, the longitudinal activity distribution around the center of the band can be determined. The half-width of the distribution is found to be varying in Cycles 21?–?23, and in some time intervals it was as narrow as 20?–?30 degrees. It was more extended around a maximum but it was also narrow when the activity jumped to the opposite longitude. Flux emergence exhibited a quasi-periodic variation within the active zone with a period of about 1.3 years. The path of the active-longitude migration does not support the view that it might be associated with the 11-year solar cycle. These results were obtained for a limited time interval of a few solar cycles and, bearing in mind uncertainties of the migration-path definition, are only indicative. For the major fraction of the dataset no systematic active longitudes were found. Sporadic migration of active longitudes was identified only for Cycles 21?–?22 in the northern hemisphere and Cycle 23 in the southern hemisphere.