Is the onset of the English summer advancing?

British summers are known to have become warmer and drier in recent decades, but has there also been a change in the timing of this season’s beginning, as has occurred for spring? This paper addresses this question by examining records of the first blooming date of early summer flowering plants (phenology) and the timing of first occurrences of warm ‘summer’ temperatures, both events that we associate with the onset of summer. This has revealed that the onset of summer in England has been advancing since the mid 1950s. The occurrence of ‘summer’ temperatures has advanced more than early summer flowering, by eleven and three days respectively in the 1990s compared to the period 1954–1963. This may have encouraged drought or heat wave conditions by prolonging the period of warm temperatures and lower rainfall in which these events occur.     

May we engineer the climate?

Not only is the science of climate engineering uncertain; the legal issues are also highly uncertain. Although existing international law does not specifically limit the freedom of states to undertake climate engineering, the international community would likely demand a say should climate engineering move from the realm of speculation to concrete proposals. The experience of other environmental regimes, however, suggests that developing an international decision-making mechanism would be difficult, and that the international community might opt for a simple prohibition on climate engineering on grounds of precaution.     

Will the Globe Encounter the Warmest Winter after the Hottest Summer in 2023?

In the boreal summer and autumn of 2023, the globe experienced an extremely hot period across both oceans and continents. The consecutive record-breaking mean surface temperature has caused many to speculate upon how the global temperature will evolve in the coming 2023/24 boreal winter. In this report, as shown in the multi-model ensemble mean(MME) prediction released by the Institute of Atmospheric Physics at the Chinese Academy of Sciences, a medium-to-strong eastern Pacific El Ni?o event wil...     

LULUCF in the post-2012 regime: fixing the problems of the past?

One of the reasons why the Kyoto Protocol has been environmentally ineffective is the flaws in the land use, land-use change and forestry (LULUCF) accounting rules, including voluntary accounting for Article 3.4 activities, the adoption of a definition of forest management that allowed parties to preferentially include and exclude forest lands, and allowing parties with net emissions from LULUCF in 1990 to include deforestation emissions in their 1990 emissions base year. Three proposed amendments to the LULUCF rules for the post-2012 regime are discussed and analysed: (1) a force majeure rule, (2) a baseline-and-credit system for forest management and (3) an ‘emissions-to-atmosphere’ approach for harvested wood products. Although these proposals have the potential to significantly improve the accounting framework, there are still significant problems such as the failure to account for the biophysical effects of forest activities, uncertainties associated with the application of the forest management baseline-and-credit system and continuing optional coverage of Article 3.4 activities.     

What is the “sign” of the atmospheric-electric field?

Summary The sign of the vector representing the atmospheric electric field has recently been subject of debate. For the sake of clarity, it is recommended to refer only to a normal or reversed clear-weather potential gradient.

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Zusammenfassung Eine in letzter Zeit entstandene Diskussion darüber, welches Vorzeichen dem Vektor des atmosphärisch-elektrischen Feldes bzw. des Potentialgefälles zuerkannt werden soll, erscheint wenig sinnvoll. Zur Vermeidung künftiger Unklarheiten wird empfohlen, bei der atmosphärischen Elektrizität nur von normaler Schönwetterrichtung und umgekehrter Schönwetterrichtung des Feldes bzw. des Potentialgefälles zu sprechen.

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Résumé Une récente discussion a porté sur le signe qui devait être attribué au vecteur du champ électrique atmosphérique respectivement de son gradient de potentiel. On recommande, pour éviter à l'avenir toute confusion, de ne parler en électricité atmosphérique et quand il s'agit du champ ou du gradient de potentiel, que de «direction normale de beau temps» et de «direction inversée de beau temps».

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Dedicated to Dr.W. Mörikofer on the occasion of his 70th birthday.     

What drives the global summer monsoon over the past millennium?

The global summer monsoon precipitation (GSMP) provides a fundamental measure for changes in the annual cycle of the climate system and hydroclimate. We investigate mechanisms governing decadal-centennial variations of the GSMP over the past millennium with a coupled climate model’s (ECHO-G) simulation forced by solar-volcanic (SV) radiative forcing and greenhouse gases (GHG) forcing. We show that the leading mode of GSMP is a forced response to external forcing on centennial time scale with a globally uniform change of precipitation across all monsoon regions, whereas the second mode represents internal variability on multi-decadal time scale with regional characteristics. The total amount of GSMP varies in phase with the global mean temperature, indicating that global warming is accompanied by amplification of the annual cycle of the climate system. The northern hemisphere summer monsoon precipitation (NHSMP) responds to GHG forcing more sensitively, while the southern hemisphere summer monsoon precipitation (SHSMP) responds to the SV radiative forcing more sensitively. The NHSMP is enhanced by increased NH land–ocean thermal contrast and NH-minus-SH thermal contrast. On the other hand, the SHSMP is strengthened by enhanced SH subtropical highs and the east–west mass contrast between Southeast Pacific and tropical Indian Ocean. The strength of the GSMP is determined by the factors controlling both the NHSMP and SHSMP. Intensification of GSMP is associated with (a) increased global land–ocean thermal contrast, (b) reinforced east–west mass contrast between Southeast Pacific and tropical Indian Ocean, and (c) enhanced circumglobal SH subtropical highs. The physical mechanisms revealed here will add understanding of future change of the global monsoon.     

Technology transfer under the CDM: Materializing the myth in the Japanese context?

The paper investigates the role that the clean development mechanism (CDM) could play in enhancing the effectiveness of north–south technology transfer. This is done by first exploring the issue of technology transfer in the context of existing north–south experiences to bring out the basis for the poor and unsatisfactory performance. This is followed by bringing out the intrinsic relevance of appropriate technology transfer for combating the global climate change issue.The paper then analyses the potential for such an appropriate and sustainable transfer, as well as effective diffusion and deployment of technologies under the CDM. Various aspects of the evolving design of the CDM are investigated to analyze the potential for overcoming the historical barriers across the north–south divide.Any potential for technology transfer under the CDM would need to be supported by an effective framework in the developed countries as well as a conducive environment in developing countries. In searching for such a cooperative and complementary model, the paper analyses the current Dutch strategy to bringforth certain salient features that could be applicable for other countries.Finally, a Japanese model for technology transfer is developed which can build upon domestic strengths as adopt applicable features of the Dutch strategy in order to capitalize any latent potential under the CDM. This is done by first investigating the effectiveness of the existing Japanese technology transfer framework and then extending recommendations for adapting it to reflect the shifting resource flow paradigms under the climate change regime.     

Did the global temperature trend change at the end of the 1990s?

The apparent leveling of the global temperature time series at the end of the 1990s may represent a break in the upward trend. A study of the time series measurements for temperature, carbon dioxide, humidity and methane shows changes coincident with phase changes of the Atlantic and Pacific Decadal Oscillations. There are changes in carbon dioxide, humidity and methane measurement series in 2000. If these changes mark a phase change of the Pacific Decadal Oscillation then it might explain the global temperature behavior.     

Should the use of standardized baselines in the CDM be mandatory?

There has been considerable debate on the merits of standardized baselines (SBLs) in the clean development mechanism (CDM), and how such baselines could reduce transaction costs for CDM projects. It has not been considered whether the voluntary versus mandatory use of SBLs by CDM project developers can affect the environmental integrity of the CDM. An example is given in which SBLs are applied to a homogeneous output industry in order to illustrate how the voluntary use of SBLs could lead – even with relatively stringent benchmarks – to over-crediting of emission reduction credits.     

Climate sensitivity: should the climate tail wag the policy dog?

The small but stubbornly unyielding possibility of a very large long-term response of global temperature to increases in atmospheric carbon dioxide can be termed the fat tail of high climate sensitivity. Recent economic analyses suggest that the fat tail should dominate a rational policy strategy if the damages associated with such high temperatures are large enough. The conclusions of such analyses, however, depend on how economic growth, temperature changes, and climate damages unfold and interact over time. In this paper we focus on the role of two robust physical properties of the climate system: the enormous thermal inertia of the ocean, and the long timescales associated with high climate sensitivity. Economic models that include a climate component, and particularly those that focus on the tails of the probability distributions, should properly represent the physics of this slow response to high climate sensitivity, including the correlated uncertainty between present forcing and climate sensitivity, and the global energetics of the present climate state. If climate sensitivity in fact proves to be high, these considerations prevent the high temperatures in the fat tail from being reached for many centuries. A failure to include these factors risks distorting the resulting economic analyses. For example, we conclude that fat-tail considerations will not strongly influence economic analyses when these analyses follow the common—albeit controversial—practices of assigning large damages only to outcomes with very high temperature changes and of assuming a significant baseline level of economic growth.     

Can the Southern annular mode influence the Korean summer monsoon rainfall?

We demonstrate that a large-scale longitudinally symmetric global phenomenon in the Southern Hemisphere sub-polar region can transmit its influence over a remote local region of the Northern Hemisphere traveling more than 100° of latitudes (from ~70°S to ~40°N). This is illustrated by examining the relationship between the Southern Annular Mode (SAM) and the Korean Monsoon Rainfall (KMR) based on the data period 1983-2013. Results reveal that the May-June SAM (MJSAM) has a significant in-phase relationship with the subsequent KMR. A positive MJSAM is favorable for the summer monsoon rainfall over the Korean peninsula. The impact is relayed through the central Pacific Ocean. When a negative phase of MJSAM occurs, it gives rise to an anomalous meridional circulation in a longitudinally locked air-sea coupled system over the central Pacific that propagates from sub-polar to equatorial latitudes and is associated with the central Pacific warming. The ascending motion over the central Pacific descends over the Korean peninsula during peak-boreal summer resulting in weakening of monsoon rainfall. The opposite features prevail during a positive phase of SAM. Thus, the extreme modes of MJSAM could possibly serve as a predictor for ensuing Korean summer monsoon rainfall.     

Russian ratification process Why is the rest of the world waiting?

Abstract

Russia has a crucial veto on the entry into force of the Kyoto Protocol. The preparation of the ratification and institutional reform have begun in April 2002. The ratification process is based on the activities by high-level policy makers who have other priorities, federal level institutional actors which may be unclear about their roles and the few overloaded expert civil servants. After the US withdrawal from Kyoto, arguments against ratification have appeared in the Russian debate, mostly based on the lack of clarity of the economic benefits available. Ratification would require Russia to establish an eligibility strategy under Kyoto and divide responsibilities and rights between the government, regional and private sector actors. The legal procedure of ratification is simple but internal political complexities may delay the process.     

Is the Isentropic Surface Always Impermeable to the Potential Vorticity Substance?

The impermeability of isentropic surfaces by the potential vorticity substance (PVS) has often been used to help understand the generation of potential vorticity in the presence of diabatic heating and friction.In this study,we examined singularities of isentropic surfaces that may develop in the presence of diabatic heating and the fictitious movements of the isentropic surfaces that are involved in deriving the PVS impermeability theorem.Our results show that such singularities could occur in the upper troposphere as a result of intense convective-scale motion,at the cloud top due to radiative cooling,or within the well-mixed boundary layer.These locally ill-defined conditions allow PVS to penetrate across an isentropic surface.We conclude that the PVS impermeability theorem is generally valid for the stably stratified atmosphere in the absence of diabatic heating.