Март 2008 г.

Российская наука и мир (по материалам зарубежной электронной прессы)

CONTENTS / ОГЛАВЛЕНИЕ


• NASA Wary of Relying on Russia
• Climate change may spark conflict with Russia, EU told
• New Method to Estimate Sea Ice Thickness
• St. Petersburg to host IX International Baltic Sea Day
• Le changement climatique impacte sur la feuillaison des forêts boréales
• Fullerenes: produce and divide
• Will Russia Have A Tuberculosis Vaccine?
• New Tomb for "Altai Princess" to be Built in Siberia
• Sandia teams with Russian researchers to develop way to determine work readiness for critical operations
• Nitrites Help To Struggle Against Ischemia Retinae
• Drugs And Explosives: End-To-End Inspection
• Two Turkish Researchers Elected Members Of Russian Academy Of Sciences
• Des températures plus élevées et des hivers plus doux en Russie et au Canada

Группа французских, английских, японских и российских фенологов (фенология - система знаний о сезонных явлениях природы, сроках их наступления и причинах, определяющих эти сроки) на основе данных со спутника выяснила, как менялась дата распускания листьев в Северной Европе и Центральной Сибири. Результаты работы опубликованы в журнале Global Change Biology.

À l'aide de données satellites, des chercheurs* issus de laboratoires français dont le Centre d'études spatiales de la biosphère et le Laboratoire de glaciologie et géophysique de l'environnement, anglais, japonais et russes, ont cartographié la date d'apparition des feuilles des forêts boréales.
La phénologie étudie les variations, en fonction du climat, des phénomènes périodiques de la vie végétale. Dans leurs travaux publiés dans le numéro de mars de "Global Change Biology"**, les chercheurs ont mis en évidence une avancée de la feuillaison, apparue entre 1987 et 1990, sur une très large portion de l'Eurasie boréale et plus marquée en Sibérie Centrale, traduisant une augmentation sans précédent de la température printanière depuis 1921. Les chercheurs ont observé une température printanière anormalement élevée dans les années 1990 en Sibérie Centrale, où l'apparition des feuilles a été la plus précoce depuis 1921. Ils ont aussi noté une température printanière particulièrement basse en 1983 et 1984, l'apparition des feuilles durant ces deux années ayant été la plus tardive depuis 1921. Ces résultats confirment que les tendances observées par télédétection doivent être analysées avec précision, souligne l'étude.
Plus tôt dans le siècle, l'Eurasie boréale a connu d'autres périodes de réchauffement durant lesquelles les feuilles sont apparues de plus en plus tôt. Cela a été le cas par exemple entre 1936 et 1944 en Sibérie Centrale et à plusieurs reprises en Russie de l'Ouest. Il y a eu aussi des périodes de refroidissement se traduisant par un retard progressif de l'apparition des feuilles, notamment entre 1945 et 1960 en Sibérie centrale et orientale. Mais ces tendances se produisaient toujours à une échelle locale ou régionale, relèvent les scientifiques.
En comparant ces résultats aux données disponibles pour la période située avant 1982, les chercheurs ont retracé l'évolution de la feuillaison sur l'ensemble du 20ème siècle. Du point de vue du réchauffement climatique, l'avancée récente de la feuillaison, observée par télédétection, en Eurasie boréale indique une augmentation à grande échelle de la température printanière depuis 1921.
* Centre d'études spatiales de la biosphère (CESBIO/OMP, CNRS, Université Toulouse 3, IRD, CNES), Laboratoire de glaciologie et géophysique de l'environnement (LGGE/OSUG, CNRS et Université Grenoble 1), JAMSTEC-Frontier research center for global change (Yokohama, Japon), Centre for terrestrial carbon dynamics (Sheffield, GB), University of Sheffield (Sheffield, GB) et Komarov institute of botany (Saint-Pétersbourg, Russie).
** Delbart, N., Picard, G., Le Toan, T., Kergoat, L., Quegan, S., Woodward, I, Dye, D., and Fedotova, V., Spring phenology in boreal Eurasia in a nearly century time-scale, Global Change Biology, 14 (3), 603-614, doi:10.1111/j.1365-2486.2007.01505.x

В России создан уникальный комплекс для промышленного производства фуллеренов. Разработан он в ЗАО "Инновации ленинградских институтов и предприятий".

(Nanowerk News) The unique complex designed and built from several units by specialists of the Closed Joint-Stock Company "Innovations of the Leningrad Institutes and Enterprises" (St. Petersburg) enables to produce kilograms of fullerenes per day - amazing hollow "globules", "ellipsoids of rotation" - molecules consisting of several dozens of carbon atoms each. And most importantly, the complex allows, if necessary, to divide them by the molecular mass, i.e., to single out the most investigated and often used fullerenes, molecules of which consist of 60 and 70 carbon atoms, as well as a fraction consisting of a mixture of heavier fullerene modifications - containing 76, 78, 84, 90 and more atoms of carbon.
It should be noted that relatively not long ago, fullerenes were rather exotic objects, which were actively studied but which were not practically used. But, as the scientists often put it, fullerenes are too perfect to be useless. Indeed, it has turned out that fullerenes per se and materials based on them or even the materials that contain a relatively small quantity of fullerenes or their derivatives in their composition possess various interesting and sometimes exceptionally useful properties. Fullerenes can act as catalysts and cocatalysts in a wide class of organic synthesis reactions, they are able to increase durability and elasticity of materials, fullerenes help to change optical properties of materials - their thermal and electroconductivity. However, industrial processes require large-scale quantities of these surprising compounds, but the most well-known methods for obtaining fullerenes allow to produce very little of them, and in the mixture with other carbon retrofits - in the so-called fullerene soot along with graphite, amorphous carbon, carbonic nanotubes and other structures. Besides, properties of different fullerenes vary, consequently, to control the final material properties, it is necessary to use only fullerenes of a certain kind. It means that specialists should know how to divede them, this being also done in large-scale quantities, not in laboratory amounts.
The complex designed by the authors from St. Petersburg enables to produce fullerenes in significant quantities and to single out their target types, which are practically not contaminated by other carbonic products. The complex contains several basic units. The first unit is a 25-liter reactor per se for obtaining the primary product of fullerene mixture of particularly pure graphite rods - up to 120 grams per hour. This is the so-called fullerene soot, but fullerenes already make 12% to 14% of the mass. For the time being, it is still a mixture, but it mainly consists of the C60 fullerenes (65% to 70%), 23% to 27% - are the C70 fullerenes, and the rest is the mixture of heavier fullerenes.
The next unit is an extractor. Its task is to isolate the fullerene mixture from soot, the extractor productivity being about 400 grams of fullerene per one five-hour cycle (the extractor useful capacity is 1.8 l). The authors have designed an exclusively productive extractor - it enables to isolate practically all fullerenes from soot (more than 98%).
And finally, the closing unit of the complex is the separator system for obtaining individual fullerenes, first of all, the most demanded and the lightest type of fullerenes - C60. With the capacity of 10 l, it enables to produce 100 grams of fullerene per day, the product purity being rather high - 99.5% to 99.9%. Besides, there are special separators for isolation of heavier fractions, if needed. Thus, the complex allows to get absolutely exotic kinds of fullerenes, such as C84 and C90, they are also very pure but are obtained in lower quantities - however, the demand for them is significantly lower. As for the C70 fullerene, the complex manages to produce up to 20 grams of it per cycle, the cycle making two days in this case.
Certainly, this is only a list of main stages of the process developed by the researchers and, accordingly, only main types of required equipment. However, the authors did not only develop, patent and design the entire complex and all fundamental processes, but they even built real, production prototypes, not laboratory samples. The complex is operating, so as much fullerene as needed can be produced now. So far, kilograms of fullerenes are required, but most probably more will be needed in near future.

Специалисты ФГУН ГНЦ вирусологии и биотехнологии "Вектор" проводят испытания нового экспериментального препарата вакцинопрофилактики туберкулёза.

Specialists of the State Research Center for Virology and Biotechnology "Vector" have tested on mice a new experimental preparation for tuberculosis vaccinal prevention (it cannot be called a vaccine yet, as it has not received all required verifications and approvals). The preparation is nontoxic and does not provoke the animals' immune response.
Tuberculosis that takes away lives of two million people remains a very dangerous disease. Physicians all over the world are working to produce efficient tuberculosis vaccines, but their effort has not succeeded yet. All preparations available do not ensure complete protection from the disease. For example, efficiency of one of the most widespread vaccines BCG varies from 80% to 0%. The experimental vaccine, the Novosibirsk researchers are working at, is a DNA fragment that codes the ESAT-6 mycobacterial antigen. Production of such a vaccine became possible after thorough investigation of genomes of mycobacteria causative agent of tuberculosis and of a congener bacterium Mycobacterium bovis.
The majority of existing tuberculosis vaccines represent weakened mycobacteria cultures: a vaccine is supposed to provoke the immune response, but not the disease. The bacteria are weakened by removing from them the genes that are responsible for virulent properties, including the gene that codes the ESAT-6. It is absent from all existing Mycobacterium bovis BCG vaccine cultures. The Novosibirsk researchers staked specifically on this protein, which should not pose danger by itself.
Having established a proper genetically engineered construction, the researchers surrounded it by a polysacharide covering of polyglucin and spermidine. The covering reliably protects the DNA from enzymes that can destroy it. In the organism, polyglucin gradually decomposes, and the DNA becomes accessible to the immune system cells. The mice were immunized by the obtained preparation for three times. The preparation was injected intramuscularly at a two-week interval. The reference group animals were immunized by polysaccharides and the DNA, which did not contain the vaccine gene.
After vaccination, the mice were observed for 10 more days, and during this period, they did not lose weight and did not show any other symptoms of health impairment. Nevertheless, the animals had to be slaughtered to investigate their immune system reaction. Vaccines should stimulate cell-mediated immunity, and indeed, lymphocyte clones were formed with mice after immunization. The lymphocyte clones started to divide actively in response to introduction of the real ESAT-6 protein, at that the reaction significantly exceeded the background reaction. As for the reference group mice, their lymphocytes did not react to the protein injection. The analysis has proved that specific cell-mediated immunity was formed with vaccinated mice.
This is not a vaccine yet, it is only the first step to its development. As a matter of fact, the step has been successful.

В Горно-Алтайске строится специальное здание для хранения мумии "алтайской принцессы". В нем будет установлен стеклянный саркофаг и специальное оборудование для поддержания определенной температуры. Основные строительные работы предполагается завершить к концу 2008 года.

NOVOSIBIRSK - A tomb to house the remains of a woman found after being preserved in ice for 2,500 years will be built in Siberia's Altai Republic, the director of a local museum said on Thursday.
The well-preserved remains of the woman dubbed the Altai Princess were discovered in the region by a team led by a Novosibirsk archeologist in 1993 near the Mongolian border, and have been studied at the Archaeology and Ethnography Institute in Novosibirsk.
Residents of Altai, where shamanism is still widespread, had repeatedly called for the body's return to its homeland, and blamed the removal for earth tremors and other natural disasters.
However, Novosibirsk scientists had been reluctant to return the body, saying local museums did not have the necessary facilities to preserve it.
"A decision has been taken to build a sloping building for the mummy, resembling a burial mound. This will be an extension to the main building of the national museum" in Gorno-Altaysk, the museum director said.
The body will now be housed in a state-of-the-art glass temperature-controlled case. Construction work should be finished by the end of this year.
Russian state natural gas giant Gazprom has contributed about $11 million to the reconstruction of the museum, and the building of the tomb and sarcophagus, the head of the republic, Alexander Berdnikov, said earlier.
Scientists have no information on the actual history of the Altai Princess, but DNA tests and facial reconstruction have suggested she was ethnically European.

Российские и американские специалисты исследуют роль так называемого "человеческого фактора" в аварийных ситуациях на атомных предприятиях.

Russian researchers, wanting to reduce the number of accidents at nuclear materials facilities in their country, have teamed up with several Sandia human factors and cognition experts to figure out ways to determine on any given day if workers are ready to perform critical operations.
"The Russians came to us seeking help in developing some kind of protocol for assessing human readiness for duty," says Elaine Hinman-Sweeney (6723), who manages Sandia's US-Russian collaborations for the Nuclear Weapons Science and Technology Program. "They want to know what factors might cause a person not to do well at his or her job."
The reason for their concern is that between 1945 and 1999 a total of 22 accidents occurred in nuclear process facilities in the US, Russia, and the United Kingdom, resulting in nine fatalities and amputations in three survivors. One of the most serious was at a nuclear power reactor at Chernobyl in the Ukraine in 1986. Nuclear process facilities include both nuclear weapons laboratories and nuclear power plants where operations involve fissile materials that require physical and administrative controls to prevent critical or near-critical events from occurring.
Human error looms large
Causes for the serious accidents were due primarily to human error and included failure to follow procedures, failure to notice abnormal conditions, communication errors, and inadequate supervisory monitoring of operations. Also causing the accidents were deficiencies in training, equipment, and processes.
Promoting the joint research were representatives of VNIIEF - a Russian experimental physics laboratory. Russian researchers at St. Petersburg State University have invented a technology that evaluates readiness in people employed in that country's railroad system, looking at immediate skill levels and physiological indicators of emotion and stress resilience. The skill portion is specific to the ability to operate trains.
The Russian researchers want to adapt the same technology to the nuclear materials arena - hence the reason they turned to Sandia human factors and cognition experts for assistance.
Sandia psychologist Courtney Dornburg (12335) says one of the first activities she and Elaine engaged in was to develop a glossary of common neuroscience, cognition, and human factors terms.
"The Russians use some of the same vocabulary as we do, but in our initial conversations, we found that our words really had different meanings," Courtney says. "The glossary put us on the same page so that when we talked through an interpreter we understood each other."
Courtney and Elaine also reviewed a survey of all the accidents that occurred in the Russian nuclear weapons complex to better understand their seriousness and which could be attributed to human error and stress.
In October they spent a week in St. Petersburg, meeting with Russian professors and researchers, giving all the team members the opportunity to talk face to face. This was the third meeting between the Russians and Americans in Russia. Two other meetings were held earlier at Sandia.
As part of the October visit, the Sandians - Courtney, Elaine, Chris Forsythe (6341), and Conrad James (1744) - attended a conference on cognitive psychology and neuroscience technology. The conference emphasized a sharing of research and ideas concerning technology application of cognitive and neuroscience research. Other Americans attending the conference were representatives of the Army Aeromedical Research Laboratory, Potomac Institute for Policy Studies, and the University of Memphis.
The goal of the conference, Chris says, was to open doors for US and Russian collaborations in the area of cognition and neurotechnologies.
Courtney says the conference and other meetings made both the Americans and Russians even more aware of their different approaches.
Follow-on activity would be for the Russians to continue to develop the readiness for work detection tool and convert it to critical facilities that contain nuclear materials. Sandia would then validate their efforts.
Chris notes that Sandia's cognition work with the Russian laboratory and university will have benefits in this country.
"Concern for personnel readiness for duty exists throughout US critical nuclear weapons operations, just as it does in Russia," he says.
"The project provides an avenue for the US nuclear facilities, and other government agencies, to learn about and potentially benefit from the research and development of the Russian scientists."
Fitness for duty measurements developed for evaluation protocol
How do you measure fitness for duty? Louise Weston (12335) answered that problem for the work with the Russian researchers by developing an evaluation protocol for proposed measures of fitness for work.
Last year Louise, together with Sandia psychologist Courtney Dornburg (12335) and Kathleen Diegert, manager of Reliability Assessment and Human Factors Dept. 12335, participated in a conference at Sandia with VNIIEF staff interested in developing readiness-for-duty measures.
Using information gained from that conference and additional research, Louise wrote a SAND report that examined experimental methods of validating measures of emotional state and readiness for duty in critical operations.
The methods outlined in the report are how Sandia would go about validating work readiness measures for Russians working in critical operations.

Нитриты способны расширять сосуды при гипоксии и защищать сетчатку глаза от ишемии. К такому выводу пришли специалисты Московского научно-исследовательского института глазных болезней им. Гельмгольца и Института биохимической физики им. Н.М.Эмануэля.

Nitrites dilate vessels in case of hypoxia and protect retina from ischemia. The conclusion has been made by specialists of the Moscow Research Institute for Eye Diseases named after Gelmholtz and the N.M.Emanuel Institute of Biochemical Physics, Russian Academy of Sciences. Their discovery is the outcome of a series of experiments on rabbits. It is premature to talk about its clinical use.
Ischemia is a rather widespread pathology of retina and optic nerve. It is provoked by different reasons, including primary hypertension and insular diabetes. An important role in retina pathology development is played by shortage of nitric oxide, which is synthesized in the organism from arginine. Theoretically speaking, nitrites can turn into nitric oxide under the influence of some enzymes. However, till recently, nobody could prove that such reaction does take place in a living organism. The Moscow researchers succeeded to do that based on the acute ischemia retinae model developed by them.
The rabbit is a favorite object for ophthalmologists' investigations. The animals underwent laser coagulation of eye-ground vessels. The experimentalists have chosen such a place for exposure so that several impulses could capture the maximum number of vessels and if possible not to traumatize surrounding tissues. The laser provokes stable vasospasm and, consequently, ischemia. The outcomes of researchers' action were estimated by the rabbits' eye-ground photographs.
After coagulation, the rabbits' eye vessels become desolate and abruptly reduced in diameter. Right after laser exposure, sodium nitrite in physiological solution was intraperitoneally introduced to the rabbits on the basis of 20 mg per 1 kilogram of live weight. As soon as a quarter of an hour after the injection, the retina vessels directly behind the laser impact zone began to fill with blood and the blood circulation restored in them. At that, the nitrite injection to an animal with normal vessels almost did not provoke their dilation. The researchers assume that nitrite in the organism is able to quickly reduce to nitric oxide, which sharply relaxes vessels, but only in case of oxygen shortage.
In the course of a next series of experiments the researchers clarified if preliminary nitrite injection prevented vessel constriction. For this end, a rabbit was initially injected sodium nitrite, and 15 minutes later the researchers cauterized vessels by laser and observed changes in them. In this case, laser impact provoked only a short-term vasospasm of the vessel, which quickly filled with blood and restored the "flow capacity".
The same results were obtained by the researchers via an independent method when observing changes in photoelectric activity of a rabbit's retina. The electroretinogram analysis has shown that laser coagulation of vessels impairs functional state of retina, which restores within 7 days without outside interference. The sodium nitrite injection right after laser coagulation accelerates the rehabilitation process significantly, and the preparation injection prior to laser exposure virtually fully protects retina from injury. At that, even strong laser impact can not provoke abrupt constriction and desolation of animals' vessels.
Thus, the outcomes obtained by two independent methods prove that nitrites presence in vessels protects the retina from acute ischemia. Mechanism of such action, apparently, consists in the fact that under oxygen shortage in the organism, sodium nitrite can reduce to nitric oxide at concentrations that are sufficient for full vessel relaxation.

Ученые Института физики твердого тела РАН и Объединенного института ядерных исследований разрабатывают установку для экспресс-выявления взрывчатых, токсичных и наркотических веществ.

Specialists from the Institute of Solid State Physics, Russian Academy of Sciences (town of Chernogolovka, Moscow Region), together with their colleagues from Joined Institute for Nuclear Research and the ASPECT Close Joint-Stock Company - Research and Production Center (town of Dubna, Moscow Region) are developing antiterrorist transmission device for express detection of explosives, toxic and narcotic substances. The future device operation is based on object translucence by a fast neutron flux and on subsequent recording of spectra of roentgen fluorescence induced by neutrons. Certainly, this is not the safest method for dangerous substances detection - people should be at the twenty to thirty meter distance during the inspection. But, on the other hand, the method is very efficient - nothing can be hidden from such control. It takes only five minutes to get complete information about the object - its 3D image, including all articles hidden inside the object and their chemical composition. So, one can quickly detect what is hidden inside a truck or a carriage, for example, where heroin or trinitrotoluene is concealed, and where there are simply sugar bags without any dangerous "enclosure".
The device under design has several peculiarities, two of which are most important. One of them is the original neutron scanner construction of a new type based on thin-walled sapphire tubes, and the second is the original construction of X-radiation detectors that are made in the form of 3D matrices of reciprocally intersecting scintillation fibers. These peculiarities enable to perform the inspection quicker, more conveniently and precisely than similar-purpose devices existing so far. Besides, the device dimensions and its power consumption will also decrease significantly.
The device will operate approximately as follows. In the neutron scanner, the flux of deuterons (accelerated in a specially grown sapphire tube) hits the tritium target set at the tube butt-end. At that, each reaction (one hit) forms a fast neutron and an alpha particle (helium nucleus) flying directly in the opposite direction. It is difficult to directly characterize these neutrons (to measure the direction, velocity and energy of each neutron), but it is easy to do than indirectly - with the help of alpha particles paired to them. If a fast neutron flies through the tube walls and further through the object, alpha particles are held back by a thin film of a substance that glows upon interaction with an alpha particle. As a result, it can be determined how many neutrons were formed and in what direction and at what time they "flew out". This is the first step - to detemine characteristics of scanning irradiation.
When a fast neutron collides with an atom, it "induces" the atom for a short while. Coming back to the initial condition, the induced atom nucleus generates (emits) a gamma-quantum with certain energy, this energy being the value typical of atoms of each element. Consequently, recording of such secondary gamma-quantums can determine what elements the object under investigation is made of. Certainly, the "gross" analysis is of no interest - a 3D image is needed to detect where materials of the target composition are located. The detector based on multiple piled thin scintillation fibers (a row is placed lengthwise, another row is placed across like a pile of logs, thus making ten rows altogether) enables to record the source of specified gamma radiation with precise indication to disposition of its thin scintillation fibers, which researchers from the Institute of Solid State Physics (Russian Academy of Sciences) have learnt to grow from melt.
As a result, knowing parameters of the "hitting" neutron flux and precise characteristics of each of neutrons, as well as parameters of induced gamma radiation, one can in principle reveal the genuine contents of the object (of course with the help of a PC and proper software) and to find dangerous articles where no other devices or specially trained keen-nosed dog can detect it. "To be more precise, adds one of the authors, Nikolai Klassen, Ph. D. (Physics&Mathematics), devices based on fast neutrons do exist in principle. But our device is more compact (therefore, it can be produced in a portable version, which is very important for antiterrorist and drug controlling that becomes possible in any location where a suspicious automobile is stopped) and it provides information quicker, to a fuller extent and in a less expensive way." In fact, the device per se does not exist yet. Its design has been developed, individual elements are ready, developed and tested. However, some components of the future device exist only "on paper" for the time being - the researchers know how to produce them but the implementation requires funding. Since the work is extremely important not only for scientists but for everybody in general, the funds will hopefully be raised.

Иностранными членами РАН стали двое турецких ученых.

ANKARA - Scientific and Technological Research Council of Turkey (TUBITAK) Marmara Research Center (MAM) Deputy Chairman Prof. Dr. Onder Yetis and MAM Material Institute Chief Expert Prof. Dr. Kerim Allahverdi were elected members of Russian Academy of Sciences. Turkish researchers Yetis and Allahverdi will contribute to Turkey's science and competitive power and have opportunity to follow scientific developments in Russia and other countries. The academy is a network of scientific institutes from all across the Russian Federation engaged in research, as well as auxiliary units - scientific like libraries and publishers, and social, e.g. hospitals. It consists of 9 branches by scientific domain, of 3 territorial branches and of 14 regional scientific centres. The Academy has numerous councils, committees and commissions, organized for a different purposes.

Британское метеорологическое бюро отметило, что за последние 50 лет средняя температура зимой в России и Канаде повысилась на 4°C. По мнению Бюро, это неоспоримое доказательство изменения климата.

Le Bureau Météorologique Britannique a indiqué que les hivers étaient beaucoup plus doux en Russie et au Canada, avec des températures supérieures de 4°C pour les jours les plus froids d'hiver par rapport aux températures des années 1950. Il s'agit d'une conséquence du changement climatique.
Les jours les plus froids d'hiver en Russie et au Canada sont 4°C plus chauds depuis les années 1950, et selon le British Meteorological Office (Bureau de Météorologie Britannique) c'est un signe clair du changement climatique.
Une étude des températures minimum et maximum quotidiennes indique qu'une tendance vers des nuits plus douces et des jours plus chauds devrait apporter plus de canicules et des modifications des saisons de pousse des cultures.
"Les températures minimum ont connu les augmentations les plus importantes, surtout en Russie et au Canada, où les jours les plus froids sont désormais 4°C plus chauds que ce qu'ils étaient au milieu du 20ème siècle" a déclaré le Hadley Centre du Bureau de Météorologie Britannique. Un communiqué publié par le Centre Hadley indique également que les changements les plus importants en matière de températures maximum ont eu lieu "au Canada et en Eurasie avec une augmentation de 1°C à 3°C des températures maximum".
En Grande-Bretagne, le réchauffement climatique se traduit par une augmentation des températures maximum de 0,5°C à 3°C par rapport aux années 1950. L'étude, publiée dans le Journal of Geophysical Research, montre aussi que "certains phénomènes extrêmes augmentent déjà" notamment en Russie et au Canada, a expliqué Simon Brown, scientifique climatique pour le Bureau Météorologique Britannique.
"La tendance devrait se poursuivre étant donné que le changement climatique aura un impact significatif, avec des nuits plus douces et des jours plus chauds à l'avenir" a-t-il indiqué.
L'année dernière, le Groupe Intergouvernemental d'Experts des Nations Unies sur l'Evolution du Climat (GIEC) avait prévu que les températures du monde augmenteraient de 1,8°C à 4,0°C d'ici 2100 à cause de l'augmentation des émissions de gaz à effet de serre. Au cours du 20ème siècle les scientifiques ont enregistré une augmentation des températures de 0,7°C. Une canicule en Europe pendant l'été 2003 a fait entre 22000 et 35000 victimes et près de 14 milliards de dollars de pertes agricoles, d'après le Bureau Météorologique Britannique.
Mais certains experts disent que les hivers plus chauds pourront aussi avoir des effets positifs tels que la chute du nombre de décès liés à un froid extrême, surtout dans les pays froids tels que le Canada et la Russie. En plaisantant, le Président russe Vladimir Poutine avait déclaré en 2002 que les hivers plus chauds permettraient au moins de réduire les dépenses des russes liées à l'achat des manteaux de fourrures.

Начало дайджеста за МАРТ 2008 года (часть 1)

предыдущий месяц

1998-2008

следующий месяц