Global change

1] Aerosol hygroscopicity has a significant effect on radiative properties of aerosols. Here a lidar method, applicable to cloud-capped, well-mixed atmospheric boundary layers, is employed to determine the hygroscopic growth factor f(RH) under unperturbed, ambient atmospheric conditions. The data used for the analysis were collected under a wide range of atmospheric aerosol levels during both routine measurement periods and during the intensive operations period (IOP) in May 2003 at the Southern Great Plains (SGP) Climate Research Facility in Oklahoma, USA, as part of the Atmospheric Radiation Measurement (ARM) program. There is a good correlation ($0.7) between a lidar-derived growth factor (measured over the range 85% RH to 96% RH) with a nephelometerderived growth factor measured over the RH range 40% to 85%. For these RH ranges, the slope of the lidar-derived growth curve is much steeper than that of the nephelometerderived growth curve, reflecting the rapid increase in particle size with increasing RH. The results are corroborated by aerosol model calculations of lidar backscatter and nephelometer equivalent f(RH) based on in situ aerosol size and composition measurements during the IOP. It is suggested that the lidar method can provide useful measurements of the dependence of aerosol optical properties on relative humidity and under conditions closer to saturation than can currently be achieved with humidified nephelometers.

The United Nations Conference on Sustainable Development, held in June 2012 in Rio de Janeiro, was probably the largest event in a long series of megasummits on environmental protection and sustainable development. Roughly 44 000 participants descended on Rio de Janeiro to take part in ten days of preparatory committee meetings, informal consultations, side events, and the actual conference. Yet despite this unprecedented high attendance by participants from governments and civil society, the outcome of the conference is less than many had hoped for. In this paper I review the outcomes of the 2012 Rio conference in detail, with a special focus on its contributions towards the reform of the institutional framework for sustainable development. Following this review, I discuss the way ahead and options for structural reform to restrengthen earth system governance.

During the last glacial-interglacial cycle, northern hemispheric (NH) ice-sheets experienced dramatic changes in radiative forcing, due to orbitally-driven insolation changes and varying greenhouse gas concentrations. This direct forcing caused temperature changes and eventually ablation anomalies. Orbital-scale variations in the atmospheric circulation caused anomalies in temperature advection and precipitation/snowfall that also strongly contributed to the mass balance and hence the time-evolution

The impact of time-varying radiative forcing on the diagnosis of radiative feedback from satellite observations of the Earth is explored. Phase space plots of variations in global average temperature versus radiative flux reveal linear striations and spiral patterns in both satellite measurements and in output from coupled climate models. A simple forcingfeedback model is used to demonstrate that the linear striations represent radiative feedback upon nonradiatively forced temperature variations, while the spiral patterns are the result of time-varying radiative forcing generated internal to the climate system. Only in the idealized special case of instantaneous and then constant radiative forcing, a situation that probably never occurs either naturally or anthropogenically, can feedback be observed in the presence of unknown radiative forcing. This is true whether the unknown radiative forcing is generated internal or external to the climate system. In the general case, a mixture of both unknown radiative and nonradiative forcings can be expected, and the challenge for feedback diagnosis is to extract the signal of feedback upon nonradiatively forced temperature change in the presence of the noise generated by unknown time-varying radiative forcing. These results underscore the need for more accurate methods of diagnosing feedback from satellite data and for quantitatively relating those feedbacks to long-term climate sensitivity.

Elucidating the role of pyrogenic carbon (C pyr) as a global pool for CO 2 sequestration in temperate ecosystems requires information on the contribution of C pyr to soil organic carbon (SOC) across different climatic regions. We investigated the effect of climate and basic soil properties on the accumulation of C pyr in surface soils across the native North American prairies. Topsoil samples (0-10 cm) of 18 native grassland sites along temperature and precipitation transects from central Saskatoon, Canada, to south Texas, USA, were analyzed for benzenecarboxylic acids as molecular markers for C pyr after nitric acid oxidation in the bulk soil (<2 mm), clay-(<2 mm) and silt-sized (2-20 mm) separates. C pyr contributed between 4 and 18% to SOC, the major proportions of C pyr being mostly found in the clay and silt fractions. C pyr in soil did not correlate with basic inorganic soil properties such as pH or clay content, but it increased significantly as SOC contents increased (r 2 = 0.78; P < 0.001). Obviously, C pyr co-accumulated with dead biomass. Since this accumulation depends on climate, also C pyr contents in soil depend on climate and may be predicted by the logarithm of the ratio of mean annual temperature (MAT) to mean annual precipitation (MAP) (P < 0.05). We conclude that the natural potential of soils to sequester C pyr reflects both, (1) higher C pyr production at sites with high plant biomass in moist climates, and (2) lower C pyr residence time at soils acting as a CO 2 source in warm climates.

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3 4 • Foreword 5 • Science Highlights 7 • Why Study the Oceans? IN THIS ISSUE OF the IGBP Science Series, we report the achievements and scientifi c highlights of The Joint Global Ocean Flux Study (JGOFS). JGOFS began its active research phase in 1988 and has grown to include the work of many 100's of scientists and students in over 20 seagoing nations on the seven continents and all the principal oceans of our planet.

Climate change is one of the most influential drivers of biodiversity. Speciesspecific differences in the reaction to climate change can become particularly important when interacting species are considered. Current studies have evidenced temporal mismatching of interacting species at single points in space, and recently two investigations showed that species interactions are relevant for their future ranges. However, so far we are not aware that the ranges of interacting species may become substantially spatially mismatched. We developed separate ecological-niche models for a monophagous butterfly (Boloria titania) and its larval host plant (Polygonum bistorta) based on monthly interpolated climate data, land-cover classes, and soil data at a 10 0 -grid resolution. We show that all of three chosen global-change scenarios, which cover a broad range of potential developments in demography, socio-economics, and technology during the 21st century from moderate to intermediate to maximum change, will result in a pronounced spatial mismatch between future niche spaces of these species. The butterfly may expand considerably its future range (by 124-258%) if the host plant has unlimited dispersal, but it could lose 52-75% of its current range if the host plant is not able to fill its projected ecological niche space, and 79-88% if the butterfly also is assumed to be highly dispersal limited. These findings strongly suggest that climate change has the potential to disrupt trophic interactions because co-occurring species do not necessarily react in a similar manner to global change, having important consequences at ecological and evolutionary time scales.

This paper describes two case studies of demand-side water management in the Okanagan region of southern British Columbia, Canada. The case studies reveal important lessons about how local context shapes the process of adaptation; in these cases, adaptation to rising and changing water demand under a regime of increasingly limited supply in a semi-arid region. Both case studies represent examples of water meter implementation, specifically volume-based pricing in a residential area and as a compliance tool in a mainly farming district. While the initiative was successful in the residential setting, agricultural metering met with stiff resistance. These cases suggest many factors shape the character of the adaptation process, including: interpretation of the signal relative to context, newness of the approach, consumer values, and local and provincial political agendas. Although context has been explored in resource management circles, thus far climate change adaptation research has not adequately discussed the embeddedness of adaptation. In other words, how context matters and what aspects of context, unrelated to climate change, could encourage or thwart the act of adapting. This study is a simple illustration of the potential drivers, barriers and enabling factors that have influenced the adaptation process of water management decisions in the Okanagan.

A tropical ombrotrophic peatland ecosystem is one of the largest terrestrial carbon stores. Flux rates of carbon dioxide (CO 2 ) and methane (CH 4 ) were studied at various peat water table depths in a mixed-type peat swamp forest floor in Central Kalimantan, Indonesia. Temporary gas fluxes on microtopographically differing hummock and hollow peat surfaces were combined with peat water table data to produce annual cumulative flux estimates. Hummocks formed mainly from living and dead tree roots and decaying debris maintained a relatively steady CO 2 emission rate regardless of the water table position in peat. In nearly vegetation-free hollows, CO 2 emission rates were progressively smaller as the water table rose towards the peat surface. Methane emissions from the peat surface remained small and were detected only in watersaturated peat. By applying long-term peat water table data, annual gas emissions from the peat swamp forest floor were estimated to be 3493 AE 316 g CO 2 m À2 and less than 1.36 AE 0.57 g CH 4 m À2 . On the basis of the carbon emitted, CO 2 is clearly a more important greenhouse gas than CH 4 . CO 2 emissions from peat are the highest during the dry season, when the oxic peat layer is at its thickest because of water table lowering.

1] The global oceans serve as the largest sustained natural sink for increasing atmospheric carbon dioxide (CO 2 ) concentrations. As this CO 2 is absorbed by seawater, it not only reacts causing a reduction in seawater pH (or acidification) but also decreases the carbonate mineral saturation state (W), which plays an important role in calcification for many marine organisms. Ocean acidification could affect some of the most fundamental biological and geochemical processes of the sea in coming decades. Observations obtained in situ from Volunteer Observing Ships and multiple geochemical surveys have been extended using satellite remote sensing and modeled environmental parameters to derive estimates of sea-surface alkalinity (A T ) and carbon dioxide partial pressure (pCO 2,sw ). Pairing estimates of A T and pCO 2,sw have permitted characterization of the changes in sea-surface W, which have transpired over the past decade throughout the Greater Caribbean Region as a consequence of ocean acidification. The results reveal considerable spatial and temporal variability throughout the region. Despite this variability, we observed a strong secular decrease in aragonite saturation state (W arg ) at a rate of approximately À0.012 ± 0.001 W arg yr À1 (r 2 = 0.97, P < 0.001).

In der gesamten Biosphäre üben schnelle und sich beschleunigende Veränderungen in der Landnutzung, des Klimas und der atmosphärischen Zusammensetzung, die vor allem durch anthropogene Kräfte angetrieben werden, gröXten Einfluss auf die Produktivität, die Biodiversität und die nachhaltige Bereitstellung von Ökosystemgutern und -leistungen aus. Bisher konzentrierten sich viele Untersuchungen, die ökologische Konsequenzen des globalen Wandels abschätzen, auf einzelne trophische Level. Das Verständnis dieser Veränderungen und die Vorhersage ihrer Konsequenzen kann jedoch davon profitieren, dass enträtselt wird, wie die Interaktionen zwischen den Primärproduzenten und den primären und sekundären Konsumenten (Pflanzen, Herbivore und Karnivore) beeinflusst werden. Naturschutz und -wiederherstellung kann verbessert werden, wenn die Arten und ihre Interaktionen auf angemessenen Skalen und unter Berücksichtigung, dass ober-und unterirdische Biota ökologisch miteinander verbunden sind, eingeschätzt werden. Der Selektionsdruck auf eine Art kann von anderen Arten abhängen, so dass der Verlust einer Art mehr für die Diversität bedeutet als nur den reinen Verlust eines Taxons. Er kann ebenso den Verlust anderer Arten des gleichen oder eines anderen trophischen Levels zur Folge haben sowie die Abschwächung oder sogar den Verlust von verschiedenen Selektionsdrücken. Wir geben einen Überblick über die Diskussionen zu trophischen Interaktionen in einer sich verändernden Welt in Bezug auf (i) die Skala der Ökosystemantwort auf Umweltveränderungen mit Betonung des Bodensubsystems, (ii) die Verbindung zwischen oberund unterirdischen Subsystemen und (iii) die natürliche Selektion und die Stabilität der Gemeinschaftsstruktur sowie der Ökosystemfunktion. Wir diskutieren die Notwendigkeit isolierte Subdisziplinen der Ökologie zusammen zu führen, um die Implikationen des globalen Wandels für Ökosystemprozesse zu verstehen.

1] We have incorporated the cycling of water isotopes into the NCAR atmospheric general circulation model, CAM2. Isotope dynamics mostly follow those of previous isotope GCMs, with fractionation being produced by evaporation at the surface and by cloud processes. A new feature that we have added is the direct estimation of the degree of isotopic equilibration between vapor and raindrops as a function of temperature and rain rate. The model yields a reasonable global pattern of water isotopes in precipitation, but detailed comparison with observations is limited by known inaccuracies in precipitation and temperatures yielded by CAM2. We use the results to evaluate the fundamental controls on water isotopic composition in precipitation. We emphasize that, over much of the surface of the Earth, the concept of Rayleigh distillation is inadequate to understand the large-scale geographic distribution of water isotopes in precipitation, because the effects of surface fluxes are more important than those of distillation, in particular at low and midlatitudes and over the oceans. In oceanic regions the balance between precipitation and evaporation (P À E), which reflects the large-scale atmospheric circulation, is the primary determinant of the isotopic composition of precipitation and vapor. Variations of P À E at low latitudes over the oceans produce about 7% variation of precipitation d 18 O that is independent of temperature variation. Where P > E, the convergence of atmospheric vapor derived from various sources leads to low values and a particularly wide range in d ppt . In the tropical and subtropical troposphere the vertical decrease of d 18 O in vapor is different from the values expected from Rayleigh distillation because of entrainment, convective mixing, detrainment, evaporation of detrained water, and subsidence of low-d 18 O highaltitude air. The low d 18 O of atmospheric vapor over the oceans at high (ca. 55°) latitudes produces, as a result of kinetic effects associated with evaporation, a zone of heavy (high-d 18 O) evaporation from the oceans. This effect may account for the low d 18 O of some high-latitude ocean surface waters and also helps attenuate the effects of global temperature changes on the isotopic composition of polar precipitation.

The total ozone mapping spectrometer (TOMS), first flown on the Nimbus 7 satellite, has delivered an unanticipated set of unique information about volcanic plumes because of its contiguous spatial mapping and use of UV wavelengths. The accuracies of TOMS sulfur dioxide retrievals, volcanic plume masses, and eruption totals under lowlatitude conditions are evaluated using radiative transfer simulations and error analysis. The retrieval algorithm is a simultaneous solution of the absorption optical depth equations including ozone and sulfur dioxide at the four shortest TOMS wavelengths and an empirical correction based on background condition residuals. The retrieval algorithm reproduces model stratospheric sulfur dioxide plume amounts within _+ 10% over most central scan angles and moderate solar zenith angles if no aerosols or ash are present. The errors grow to 30% under large solar zenith angle conditions. Volcanic ash and sulfate aerosols in the plume in moderate optical depths (0.3) produce an overestimation of the sulfur dioxide by 15-25% depending on particle size and composition. Retrievals of tropospheric volcanic plumes are affected by the reflectivity of the underlying surface or clouds. The precision of individual TOMS SO2 soundings is limited by data quantization to +_6 Dobson units. The accuracy is independent of most instrument calibration errors but depends linearly on relative SO2 absorption cross-section errors at the TOMS wavelengths. Volcanic plume mass estimates are dependent on correction of background offsets integrated over the plume area. The errors vary with plume mass and area, thus are highly individual. In general, they are least for moderate size, compact plumes. Estimates of the total mass of explosively erupted sulfur dioxide depend on extrapolation of a series of daily plume masses backward to the time of the eruption. Errors of 15-30% are not unusual. Effusive eruption total mass estimates are more uncertain due to difficulties in separating new from old sulfur dioxide in daily observations. 2Department Paper number 95JD01222. 0148-0227/95/95JD-01222505.00 effects of eruptions of lesser magnitude. This is important because current concerns about global warming due to the increase in anthropogenic greenhouse gases necessitate reliable climate models with concomitant detailed and accurate 14,057 14,058 KRUEGER ET AL.: VOLCANIC SO 2 MEASUREMENTS FROM TOMS

1] The Maldives experience seasonal shifts in monsoon winds from the west-northwest to northeast. The morphologic response of reef island beaches and shorelines to these predictable shifts in climate was examined on eight islands in South Maalhosmadulu Atoll based on global positioning system surveys of island shoreline planform in January and June 2002 and February 2003. Surveys show that islands exhibit large gross changes (31-120% of beach area) in shoreline position between seasons. Such changes reflect large reversals in sediment flux of 9-23 Â 10 3 m 3 on a biannual basis driven by seasonal reversals in wind and wave conditions. Annual net change is small (2-15%), suggesting islands spatially exhibit a dynamic equilibrium. An island oscillation index (I o ) is defined that describes the spatial extent of shoreline change around islands. Island shape (ellipticity, e) is found to be positively correlated with I o in the expression I o = 1.021e À 0.275, suggesting island shape is a better indicator of the susceptibility of island shorelines to morphological change than wave energy exposure.

This study is the first global effort to quantify seasonality and extent of inundation with a suite of satellite observations, including passive and active microwave along with visible and infrared measurements. A clustering technique which merges the satellite observations is used to detect inundation. Monthly flooded areas are then calculated by estimating pixel fractional coverage of flooding using the passive microwave signal and a linear mixture model with end-members calibrated with radar observations to account for vegetation cover. The global results, comprising natural wetlands, irrigated rice, and lakes/rivers, indicate a minimum inundated area for the July 1992-June 1993 period of 2.16x10 6 km 2 , about 38% of the maximum 5.75x10 6 km 2 , to be compared to maximum areas of 5.83x10 6 km 2 and 5.70x10 6 km 2 from independent data sets. Comprehensive evaluation requires substantial additions to the sparse observational record now available.

In rare circumstances, scientists have been able to revive dormant propagules from ancestral populations and rear them with their descendants to make inferences about evolutionary responses to environmental change. Although this is a powerful approach to directly assess microevolution, it has previously depended entirely upon fortuitous conditions to preserve ancestral material. We propose a coordinated effort to collect, preserve, and archive genetic materials today for future studies of evolutionary change-a "resurrection paradigm." The availability of ancestral material that is systematically collected and intentionally stored using best practices will greatly expand our ability to illuminate microevolutionary patterns and processes and to predict ongoing responses of species to global change. In the workshop "Project Baseline," evolutionary biologists and seed storage experts met to discuss establishing a coordinated effort to implement the resurrection paradigm.

To mitigate global climate change, a portfolio of strategies will be needed to keep the atmospheric CO 2 concentration below a dangerous level. Here a carbon sequestration strategy is proposed in which certain dead or live trees are harvested via collection or selective cutting, then buried in trenches or stowed away in above-ground shelters. The largely anaerobic condition under a sufficiently thick layer of soil will prevent the decomposition of the buried wood. Because a large flux of CO 2 is constantly being assimilated into the world's forests via photosynthesis, cutting off its return pathway to the atmosphere forms an effective carbon sink. It is estimated that a sustainable long-term carbon sequestration potential for wood burial is 10 ± 5 GtC y-1 , and currently about 65 GtC is on the world's forest floors in the form of coarse woody debris suitable for burial. The potential is largest in tropical forests (4.2 GtC y-1), followed by temperate (3.7 GtC y-1) and boreal forests (2.1 GtC y-1). Burying wood has other benefits including minimizing CO 2 source from deforestation, extending the lifetime of reforestation carbon sink, and reducing fire danger. There are possible environmental impacts such as nutrient lock-up which nevertheless appears manageable, but other concerns and factors will likely set a limit so that only part of the full potential can be realized. Based on data from North American logging industry, the cost for wood burial is estimated to be $14/tCO 2 ($50/tC), lower than the typical cost for power plant CO 2 capture with geological storage. The cost for carbon sequestration with wood burial is low because CO 2 is removed from the atmosphere by the natural process of photosynthesis at little cost. The technique is low tech, distributed, easy to monitor, safe, and reversible, thus an attractive option for large-scale implementation in a worldwide carbon market.

Extreme weather, sea-level rise and degraded coastal ecosystems are placing people and property at greater risk of damage from coastal hazards 1-5. The likelihood and magnitude of losses may be reduced by intact reefs and coastal vegetation 1 , especially when those habitats fringe vulnerable communities and infrastructure. Using five sea-level-rise scenarios, we calculate a hazard index for every 1 km 2 of the United States coastline. We use this index to identify the most vulnerable people and property as indicated by being in the upper quartile of hazard for the nation's coastline. The number of people, poor families, elderly and total value of residential property that are most exposed to hazards can be reduced by half if existing coastal habitats remain fully intact. Coastal habitats defend the greatest number of people and total property value in Florida, New York and California. Our analyses deliver the first national map of risk reduction owing to natural habitats and indicates where conservation and restoration of reefs and vegetation have the greatest potential to protect coastal communities. Globally, coastal flooding and sea level are expected to increase significantly by mid-century, with potentially severe consequences for coastal populations around the world 6. In the United Stateswhere 23 of the nation's 25 most densely populated counties are coastal-the combination of storms and rising seas is already putting valuable property and large numbers of people in harm's way 1-5. The traditional approach to protecting towns and cities has been to 'harden' shorelines. Although engineered solutions are necessary and desirable in some contexts, they can be expensive to build and maintain 7,8 , and construction may impair recreation, enhance erosion, degrade water quality and reduce the production of fisheries 9,10. Over the past decade, efforts to protect people and property have broadened 11 to consider conservation and restoration of marshes, seagrass beds, coastal and kelp forests, and oyster and coral reefs that buffer coastlines from waves and storm surge 12-14 and provide collateral benefits to people 15. But approaches and tools for evaluating the potential role of natural defence mechanisms lag behind those for hardening shorelines 15. Prioritizing ecosystems for conservation or restoration in service of natural hazard reduction requires knowledge of where habitats are most likely to reduce exposure to erosion and flooding from storms and future sea levels, and protect vulnerable people and property (see Supplementary Information for definitions

Inversions of borehole temperature profiles that reconstruct past ground surface temperature (GST) changes have been used to estimate historical changes in surface air temperature (SAT). Paleoclimatic interpretations of GST reconstructions are based on the assumption that GST and SAT changes are closely coupled over decades, centuries, and longer. This assumption has been the subject of some debate because of known differences between GST and SAT at timescales of hours, days, seasons, and years. We investigate GST and SAT relationships on daily, seasonal, and annual timescales to identify and characterize the principal meteorological changes that lead to short-term differences between GST and SAT and consider the effects of those differences on coupling between the two temperatures over much longer time periods. We use observational SAT and subsurface data from Fargo, North Dakota; Prague, Czech Republic; Cape Henlopen State Park, Delaware; and Cape Hatteras National Seashore, North Carolina. These records comprise intradaily observations that span parts of one or two decades. We compare subsurface temperature observations to calculations from a conductive subsurface model driven with daily SAT as the surface boundary condition and show that daily differences exist between observed and modeled subsurface temperatures. We also analyze year-to-year spectral decompositions of daily SAT and subsurface temperature time series and show that dissimilarities between mean annual GST and SAT are attributable to differences in annual amplitudes of the two temperature signals. The seasonal partitioning of these amplitude differences varies from year to year and from site to site, responding to variable evapotranspiration and cryogenic effects. Variable yearto-year differences between mean annual GST and SAT are closely estimated using results from a multivariate regression model that associates the partial influences of seasonal meteorological conditions with the attenuation of annual GST amplitudes.

Most atmospheric scientists agree that climate changes are going to increase the mean temperature in Europe with increased frequency of climatic extremes, such as drought, floods, and storms. Under such conditions, there is high probability that forests will be subject to increased frequency and intensity of stress due to climatic extremes. Therefore, impacts of climate change on forest health should be carefully evaluated. Given these assumptions, several fungal diseases on trees may become more devastating because of the following factors: (i) abiotic stresses, such as drought and flooding, are known to predispose trees to several pathogens; (ii) temperature and moisture affect pathogen sporulation and dispersal, and changes in climatic conditions are likely to favour certain pathogens; (iii) migration of pathogens triggered by climatic change may increase disease incidence or geographical range, when pathogens encounter new hosts and (or) new potential vectors; and (iv) new threats may appear either because of a change in tree species composition or because of invasive species. If infection success is dependent on temperature, higher mean temperatures may lead to more attacks. Pathogens that have been of importance in southern Europe may spread northward and also upward to mountains. Pathogens with evolutionary potential for greater damage should be identified to estimate the magnitude of the threat and to prepare for the changing conditions. A review of the above-mentioned cases is presented. Some priorities to improve the ability to predict impacts of climate change on tree diseases are discussed.

A Geographical Information System (GIS) based methodology has been used to construct the black carbon (BC) emission inventory for the Indian geographical region. The distribution of emissions from a broader level to a spatial resolution of 1°Â 1°grid has been carried out by considering micro level details and activity data of fossil fuels and bio-fuels. Our calculated total BC emissions were 1343.78 Gg and 835.50 Gg for the base years 2001 and 1991 respectively with a decadal growth of around 61%, which is highly significant. The district level analysis shows a diverse spatial distribution with the top 10% emitting districts contributing nearly 50% of total BC emission. Coal contributes more than 50% of total BC emission. All the metropolitan cities show high BC emissions due to high population density giving rise to high vehicular emissions and more demand of energy.

Most debates about global warming focus, understandably, on the future: What will happen? When and where? Who will suffer? What should we do about it? These are important questions, but they are subject to wide disagreement for the obvious reason that the future can never be predicted. Too much depends, for example, on future emissions and on feedbacks that are poorly understood or almost impossible to predict. What's more, our major scientifi c tools for looking forward-general circulation models-are open to a variety of criticisms, from both sides of the debate, even as they become more and more powerful. It would be wise, though, to pay more attention to the past. It may concern us less than the future-after all, it's over-but it provides much more solid evidence of how the climate works and what can happen to it when various factors change. In the last fi fty years, scientists in myriad fi elds have extended our knowledge of climate millions of years into the past and refi ned that knowledge to units of decades and years rather than centuries and millennia. They have done this by developing new techniques to examine new sources of data-natural records preserved in ice caps, ocean fl oor sediments, and geological formations, for example-and by generating new theories to explain the infi nitely complex global climate system. Wallace Broecker of Columbia University has been a central fi gure in this half-century of scientifi c discovery, and he and coauthor Robert Kunzig here provide an engaging account of it for a general readership. Half science journalism and half (auto)biography (it is told in the third person), Fixing Climate traces Broecker's career from his doctoral research into the causes of ice ages through later studies of the carbon cycle, ocean chemistry and currents, and glaciers and droughts. Broecker's life provides a unifying narrative, while the work of dozens of other scientists is deftly spliced into the story; this works well because Broecker has read, studied with, taught, learned from, collaborated with, or debated almost all of them. The result is a fascinating tale of the emergence of climate science from relative obscurity into a sprawling enterprise at the forefront of research and policy. Fixing Climate is at once sobering and hopeful. On the one hand, it makes it overwhelmingly clear that global warming is both real and gravely serious. The world's climate has changed dramatically over time, raising and lowering sea levels, covering continents in ice or vegetation, rearranging plants and animals on every scale we can measure. And it has sometimes been abrupt as well as persistent, swinging tens of degrees in as little as a decade or two. Throughout the record, though, one thing has always been true: changes in temperature and changes in atmospheric carbon dioxide have correlated tightly. As a matter of physics, this has been known since the 19th century; today we have more empirical evidence to support and illustrate it than anyone should need to be convinced. On the other hand, Broecker is no alarmist. In the closing chapters of the book he considers a range of options and concludes that we must fi nd ways to remove carbon directly from the atmosphere and store it, most likely in the oceans-the place it would end up eventually in any event-by technological means. He focuses on the efforts of pioneering inventors, backed by private venture capital, to develop ways to do this that would be economical and effective-provided they are developed and deployed rapidly and on a massive scale. Instead of the conventional approach to so-called carbon capture and storage-installed at power plants and other point sources of emissions-Broecker envisions thousands, perhaps millions, of small devices distributed virtually anywhere, converting CO 2 from the air into inert forms by chemical reactions. Many might accuse Broecker of an unfounded optimism about this approach to confronting global warming. Whether such technologies can work, and whether we can muster the will and the resources to realize them, are questions surrounded by as much uncertainty as the future itself. But his hunches, insights, and determined inquisitiveness have produced remarkable knowledge before, and he is surely right to question whether other solutions, such as the Kyoto Protocol, will work any better.

Currently rising CO 2 levels in atmosphere and marine surface waters as well as projected scenarios of CO 2 disposal in the ocean emphasize that CO 2 sensitivities need to be investigated in aquatic organisms, especially in animals which may well be the most sensitive. Moreover, to understand causes and effects, we need to identify the physiological processes that are sensitive to CO 2 beyond the current emphasis on calcification. Few animals may be acutely sensitive to moderate CO 2 increases, but subtle changes due to long-term exposure may already have started to be felt in a wide range of species. CO 2 effects identified in invertebrate fauna from habitats characterized by oscillating CO 2 levels include depressed metabolic rates and reduced ion exchange and protein synthesis rates. These result in shifts in metabolic equilibria and slowed growth. Long-term moderate hypercapnia has been observed to produce enhanced mortality with as yet unidentified cause and effect relationships. During future climate change, simultaneous shifts in temperature, CO 2 , and hypoxia levels will enhance sensitivity to environmental extremes relative to a change in just one of these variables. Some interactions between these variables result from joint effects on the same physiological mechanisms. Such interactions need to be considered in terms of future increases in atmospheric CO 2 and its uptake by the ocean as well as in terms of currently proposed mitigation scenarios. These include purposeful injection of CO 2 in the deep ocean or Fe fertilization of the surface ocean, which reduces subsurface O 2 levels. The resulting ecosystem shifts could develop progressively, rather than beyond specific thresholds, such that effects parallel CO 2 oscillations. It is unsure to what extent and how quickly species may adapt to permanently elevated CO 2 levels by microevolutionary compensatory processes.

1] We assembled data at a 1°latitude by 1°longitude resolution for 285 cells across India and analyzed the seasonal trends in the maximum and minimum temperature, diurnal temperature range (DTR), and cloud cover for the time period 1931 -2002. Significant increases in maximum and minimum temperature have occurred over the Deccan plateau, but in general, trends in DTR were not significant except for a decrease in northwest Kashmir in summer. The effect of cloud cover on the DTR was expectedly negative for most of the country for winter and summer seasons with significant increase in summer cloud cover in Kashmir.

It should come as no surprise that the governments and citizenries of many countries show little concern about climate change and its consequences. Behavioral decision research over the last 30 years provides a series of lessons about the importance of affect in perceptions of risk and in decisions to take actions that reduce or manage perceived risks. Evidence from a range of domains suggests that worry drives risk management decisions. When people fail to be alarmed about a risk or hazard, they do not take precautions. Recent personal experience strongly influences the evaluation of a risky option. Low-probability events generate less concern than their probability warrants on average, but more concern than they deserve in those rare instances when they do occur. Personal experience with noticeable and serious consequences of global warming is still rare in many regions of the world. When people base their decisions on statistical descriptions about a hazard provided by others, characteristics of the hazard identified as psychological risk dimensions predict differences in alarm or worry across different classes of risk. The time-delayed, abstract, and often statistical nature of the risks of global warming does not evoke strong visceral reactions. These results suggest that we should find ways to evoke visceral reactions towards the risk of global warming, perhaps by simulations of its concrete future consequences for people's home or other regions they visit or value. Increased concern about global warming needs to solicited carefully, however, to prevent a decrease in concern about other relevant risks. The generation of worry or concern about global warming may be a necessary but not sufficient condition for desirable or appropriate protective or mitigating behavior on part of the general public.

Lake littoral zones have a transitional nature and dynamic conditions, which are reflected in their CH 4 emissions. Thus, detailed studies are needed to assess the littoral CH 4 emissions in a regional scale. In this study, CH 4 fluxes were followed during the icefree seasons in 1998 and 1999 by using the static chamber method in the littoral zone of two lakes in Finland. An exceptionally high water level in 1998 caused an unusually long inundation in otherwise ephemerally flooded zone. The flooding was normal in year 1999. The factors controlling CH 4 emissions were examined and statistical response functions were constructed. Further, the effect of extended flooding on the littoral CH 4 budged was estimated. The methane flux was primarily regulated by the water level in grass and sedge dominated eulittoral zone, but not in infralittoral reed and water lily stands. Methane emissions in the sedge dominated zone decreased significantly, when the flood was high enough to submerge the venting structures of the plants. Besides water level, sediment temperature determined CH 4 emission. The cumulative CH 4 emissions from the whole littoral wetlands in wet year were 1.1 times (L. Keva Èto È n), or 0.61 and 0.79 times (L. Mekrija Èrvi) those in dry year. The crucial factor was the discrepancy between the exceptional and the average water level. The extension of inundated area does not necessarily increase CH 4 emissions if the flood reaches infrequently inundated areas, which apparently have low CH 4 production potential. This is the case especially, if the emissions in lower zones simultaneously decrease due to high water level. Our study analyses these complex responses between CH 4 emissions and water level.

An aspect of global change currently not well understood is how processes operating on spatial scales finer than those used in recent global circulation models (GCMs) contribute to changes in atmospheric composition and the subsequent changes in climate. We use the "IPAT" formulation as a framework to test relationships among social driving forces and user group greenhouse gas (GHG) emissions in northwestern North Carolina. Using regression, correlation, and bivariate mapping to examine relationships between a suite of socioeconomic variables and GHG emissions for the residential, commercial/industrial, and agricultural end-user categories, we find that various measures of population and affluence serve equally well as explanatory variables.

Observations of the tropical atmosphere are fundamental to the understanding of global changes in air quality, atmospheric oxidation capacity and climate, yet the tropics are under-populated with long-term measurements. The first three years (October 2006–September 2009) of meteorological, trace gas and particulate data from the global WMO/Global Atmospheric Watch (GAW) Cape Verde Atmospheric Observatory Humberto Duarte Fonseca (CVAO; 16° 51′ N, 24° 52′ W) are presented, along with a characterisation of the origin and pathways of air masses arriving at the station using the NAME dispersion model and simulations of dust deposition using the COSMO-MUSCAT dust model. The observations show a strong influence from Saharan dust in winter with a maximum in super-micron aerosol and particulate iron and aluminium. The dust model results match the magnitude and daily variations of dust events, but in the region of the CVAO underestimate the measured aerosol optical thickness (AOT) because of contributions from other aerosol. The NAME model also captured the dust events, giving confidence in its ability to correctly identify air mass origins and pathways in this region. Dissolution experiments on collected dust samples showed a strong correlation between soluble Fe and Al and measured solubilities were lower at high atmospheric dust concentrations. Fine mode aerosol at the CVAO contains a significant fraction of non-sea salt components including dicarboxylic acids, methanesulfonic acid and aliphatic amines, all believed to be of oceanic origin. A marine influence is also apparent in the year-round presence of iodine and bromine monoxide (IO and BrO), with IO suggested to be confined mainly to the surface few hundred metres but BrO well mixed in the boundary layer. Enhanced CO2 and CH4 and depleted oxygen concentrations are markers for air-sea exchange over the nearby northwest African coastal upwelling area. Long-range transport results in generally higher levels of O3 and anthropogenic non-methane hydrocarbons (NMHC) in air originating from North America. Ozone/CO ratios were highest (up to 0.42) in relatively fresh European air masses. In air heavily influenced by Saharan dust the O3/CO ratio was as low as 0.13, possibly indicating O3 uptake to dust. Nitrogen oxides (NOx and NOy) show generally higher concentrations in winter when air mass origins are predominantly from Africa. High photochemical activity at the site is shown by maximum spring/summer concentrations of OH and HO2 of 9 × 106 molecule cm−3 and 6 × 108 molecule cm−3, respectively. After the primary photolysis source, the most important controls on the HOx budget in this region are IO and BrO chemistry, the abundance of HCHO, and uptake of HOx to aerosol.

Idiopathic normal pressure hydrocephalus (INPH) is a potentially treatable form of dementia but its diagnosis is difficult and the effectiveness of shunting remains controversial. This study investigates the clinical outcomes of ventriculo-peritoneal shunting in a controlled trial of 33 consecutive patients with INPH. Mean age was 77.2 years (range 58-92 years) and the duration of symptoms was 4.6 years (3 months-14 years). Nineteen patients underwent shunt surgery. At 3-4 months follow-up, patients who had undergone shunt surgery, compared to those who had not (controls), had significantly better global change ratings (median Clinician's Interview Based Impression of Change with Carer Input rating of 2 [moderately improved] versus 6 [moderately worsened], respectively, p < 0.001), had increased Mini Mental State Examination scores by 5 points (p < 0.001) and were 6.3 s faster on the Timed ''up and go" test (p = 0.008). We conclude that ventriculo-peritoneal shunting is associated with improved clinical outcomes for patients with INPH.

Rapid, human-induced global change presents major challenges to researchers, policy-makers and land managers. Addressing these challenges requires an appreciation of the dynamics of ecological systems. Here, we propose ‘landscape fluidity’ as a perspective and research agenda from which to consider landscapes in the process of changing rapidly through both time and space. We define landscape fluidity as the ebb and flow of different organisms within a landscape through time. A range of existing ideas, themes and practical approaches are relevant to landscape fluidity, and we use a case study of scattered tree landscapes in south-eastern Australia to illustrate the benefits of a landscape fluidity perspective. We suggest that a focus on landscape fluidity can bring a renewed emphasis on change in landscapes and so help unify a range of currently separate research themes in biogeography, ecology, palaeoecology and conservation biology.

Aim The paper has four major objectives: (1) to determine whether diaspore mimics accurately represent dispersal dynamics of real diaspores in a free-flowing river; (2) to estimate distance travelled and reasons for stranding of floating diaspores along a free-flowing river;

Both endophytic and mycorrhizal fungi interact with plants to form symbiosis in which the fungal partners rely on, and sometimes compete for, carbon (C) sources from their hosts. Changes in photosynthesis in host plants caused by atmospheric carbon dioxide (CO 2 ) enrichment may, therefore, influence those mutualistic interactions, potentially modifying plant nutrient acquisition and interactions with other coexisting plant species. However, few studies have so far examined the interactive controls of endophytes and mycorrhizae over plant responses to atmospheric CO 2 enrichment. Using Festuca arundinacea Schreb and Plantago lanceolata L. as model plants, we examined the effects of elevated CO 2 on mycorrhizae and endophyte (Neotyphodium coenophialum) and plant nitrogen (N) acquisition in two microcosm experiments, and determined whether and how mycorrhizae and endophytes mediate interactions between their host plant species. Endophyte-free and endophyte-infected F. arundinacea varieties, P. lanceolata L., and their combination with or without mycorrhizal inocula were grown under ambient (400 lmol mol À1 ) and elevated CO 2 (ambient 1 330 lmol mol À1 ). A 15 N isotope tracer was used to quantify the mycorrhiza-mediated plant acquisition of N from soil. Elevated CO 2 stimulated the growth of P. lanceolata greater than F. arundinacea, increasing the shoot biomass ratio of P. lanceolata to F. arundinacea in all the mixtures. Elevated CO 2 also increased mycorrhizal root colonization of P. lanceolata, but had no impact on that of F. arundinacea. Mycorrhizae increased the shoot biomass ratio of P. lanceolata to F. arundinacea under elevated CO 2 . In the absence of endophytes, both elevated CO 2 and mycorrhizae enhanced 15 N and total N uptake of P. lanceolata but had either no or even negative effects on N acquisition of F. arundinacea, altering N distribution between these two species in the mixture. The presence of endophytes in F. arundinacea, however, reduced the CO 2 effect on N acquisition in P. lanceolata, although it did not affect growth responses of their host plants to elevated CO 2 . These results suggest that mycorrhizal fungi and endophytes might interactively affect the responses of their host plants and their coexisting species to elevated CO 2 .

Information related to land surface phenology is important for a variety of applications. For example, phenology is widely used as a diagnostic of ecosystem response to global change. In addition, phenology influences seasonal scale fluxes of water, energy, and carbon between the land surface and atmosphere. Increasingly, the importance of phenology for studies of habitat and biodiversity is also being recognized. While many data sets related to plant phenology have been collected at specific sites or in networks focused on individual plants or plant species, remote sensing provides the only way to observe and monitor phenology over large scales and at regular intervals. The MODIS Global Land Cover Dynamics Product was developed to support investigations that require regional to global scale information related to spatiotemporal dynamics in land surface phenology. Here we describe the Collection 5 version of this product, which represents a substantial refinement relative to the Collection 4 product. This new version provides information related to land surface phenology at higher spatial resolution than Collection 4 (500-m vs. 1-km), and is based on 8-day instead of 16-day input data. The paper presents a brief overview of the algorithm, followed by an assessment of the product. To this end, we present (1) a comparison of results from Collection 5 versus Collection 4 for selected MODIS tiles that span a range of climate and ecological conditions, (2) a characterization of interannual variation in Collections 4 and 5 data for North America from 2001 to 2006, and (3) a comparison of Collection 5 results against ground observations for two forest sites in the northeastern United States. Results show that the Collection 5 product is qualitatively similar to Collection 4. However, Collection 5 has fewer missing values outside of regions with persistent cloud cover and atmospheric aerosols. Interannual variability in Collection 5 is consistent with expected ranges of variance suggesting that the algorithm is reliable and robust, except in the tropics where some systematic differences are observed. Finally, comparisons with ground data suggest that the algorithm is performing well, but that end of season metrics associated with vegetation senescence and dormancy have higher uncertainties than start of season metrics.

Changes in boreal climate of the magnitude projected for the 21 st century have always caused vegetation changes large enough to be societally important. However, the rates and patterns of vegetation change are difficult to predict. We review evidence suggesting that these vegetation changes may be gradual at the northern forest limit or where seed dispersal limits species distribution. However, forest composition may be quite resilient to climate change in the central portions of a species range until some threshold is surpassed. At this point, changes can be rapid and unexpected, often causing a switch to very different ecosystem types. Many of these triggers for change are amenable to management, suggesting that our choice of policies in the coming decades will substantially influence the ecological and societal consequences of current climatic change.

Recent studies have confirmed the relationship between iron supply and phytoplankton growth rates in all three high-nitrate low-chlorophyll (HNLC) oceanic provinces. However, there is little evidence, so far, of the role of iron in altering the efficiency of the biological pump via increased downward export of particulate organic carbon (POC). The NE subarctic Pacific is unique among HNLC regions in that long time series pelagic observations and deep-moored sediment trap records exist which may provide the best opportunity thus far to test aspects of the iron hypothesis. Episodic elevated levels of chlorophyll a ( > 2.0 [tg L -l) were observed 6 times between 1964 and 1976 at the former site of Ocean Station Papa (OSP). In addition, between 1984 and 1990 on at least three occasions, concurrent pulses of POC and biogenic silica were recorded in deep-moored traps at OSP. Possible explanations for these events, such as lateral advection of more productive waters, iron-mediated blooms, or grazing by salp swarms are discussed and tested using an existing downward POC flux model. Owing to the episodic nature of such events, no available data are sufficiently comprehensive to unequivocally rule out any of these explanations. Nevertheless, from the data available, the occurrence of pelagic or deep water pulses, approximately once every 3 years, are most consistent with iron-mediated diatom blooms, and of the sinking of POC and biogenic silica (from such a bloom) to depth, respectively. A comparison of the timing of these iron-mediated pulses with that of the transport probabilities of atmospheric dust supply from Asia and Alaska provides an opportunity to assess the likelihood of a coupling between the atmosphere and the ocean.

Coral species composition of drilled cores from emergent bank reefs, and coral cover of the surface of old and living reefs located along the coast of the state of Bahia, Eastern Brazil, revealed that there is a marked change in the occurrence of the major building coral species in different time intervals of the reef structure, as well as in the living surface of reefs located in two different geographical sites. Holocene core sections from two reef areas (12°40 0 S-38°00 0 W and 18°00 0 S-39°00 0 W) have as major reef builders, on its topmost core interval (3 to 4 ky old), the endemic coral Mussismilia braziliensis Verrill, 1868, which also dominate on the 2.5-3.5 ky old surfaces of truncated reef tops. At the base of the cores (the 2 m lower interval, older than 4 ky BP), another endemic coral Mussismilia harttii Verrill, 1868 is the dominant reef component. The relative abundance of M. braziliensis on the living surfaces of shallow reefs from both areas, shows that in the southern area, it is up to 98% on reefs located 60 km off the coast, in depths between 3 and 4 m, but do not exceed 1.3% on the surface of the northern reefs located 1-2 km off the coast in depths 4-5 m. The Holocene falling sea level that occurred along the coast of Brazil since 5.1 ky BP, causes an increasing runoff into the area of coastal reefs. This phenomenon may have affected the nearshore reef building fauna, replacing a more susceptive coral fauna with one better adapted to low light levels and higher sediment influx. The high turbidity associated with early Holocene shelf flooding, should also be responsible for the absence of M. braziliensis during the initial stages of reef buildup in Brazil. At the present time, the rapidly increasing human pressure, due to changes in land uses of the coastal zone (increasing sedimentation rate, nutrification of coastal waters, industrial pollution) and underwater practices, such as overfishing and an intense tourism, is aggravating the recovery capacity of this already naturally threatened coral community. If this situation coupled with increasing sea surface temperature persists, modern coral reef growth, in Brazil cannot be maintained and the major reef building coral species of the reefs in Bahia, a remnant endemic coral fauna will very soon appear in the list of endangered species.