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Future climate change is usually projected by coupled earth system models under specific emission scenarios designed by integrated assessment models (IAMs), and this offline approach means there is no interaction between the coupled earth system models and the IAMs. This paper introduces a new method to design possible future emission scenarios and corresponding climate change, in which a simple economic and climate damage component is added to the coupled earth system model of Beijing Normal University (BNU-ESM). With the growth of population and technological expertise and the declining emission-to-output ratio described in the Dynamic Integrated Climate-Economy model, the projected carbon emission is 13.7 Gt C, resulting in a 2.4 °C warming by the end of the twenty-first century (2080–2099) compared with 1980–1999. This paper also suggests the importance of the land and ocean carbon cycle in determining the CO2 concentration in the atmosphere. It is hoped that in the near future the next generation of coupled earth system models that include both the natural system and the social dimension will be developed.

Most permafrost is located in the Arctic, where frozen organic carbon makes it an important component of the global climate system. Despite the fact that the Arctic climate changes more rapidly than the rest of the globe, observational data density in the region is low. Permafrost thaw and carbon release to the atmosphere are a positive feedback mechanism that can exacerbate global warming. This positive feedback functions via changing land–atmosphere energy and mass exchanges. There is thus a great need to understand links between the energy balance, which can vary rapidly over hourly to annual timescales, and permafrost, which changes slowly over long time periods. This understanding thus mandates long-term observational data sets. Such a data set is available from the Bayelva site at Ny-Ålesund, Svalbard, where meteorology, energy balance components and subsurface observations have been made for the last 20 years. Additional data include a high-resolution digital elevation model (DEM) that can be used together with the snow physical information for snowpack modeling and a panchromatic image. This paper presents the data set produced so far, explains instrumentation, calibration, processing and data quality control, as well as the sources for various resulting data sets. The resulting data set is unique in the Arctic and serves as a baseline for future studies. The mean permafrost temperature is −2.8 °C, with a zero-amplitude depth at 5.5 m (2009–2017). Since the data provide observations of temporally variable parameters that mitigate energy fluxes between permafrost and atmosphere, such as snow depth and soil moisture content, they are suitable for use in integrating, calibrating and testing permafrost as a component in earth system models.The presented data are available in the Supplement for this paper (time series) and through the PANGAEA and Zenodo data portals: time series (https://doi.org/10.1594/PANGAEA.880120, https://zenodo.org/record/1139714) and HRSC-AX data products (https://doi.org/10.1594/PANGAEA.884730, https://zenodo.org/record/1145373).

The temperature dependency of ocean–atmosphere gas transfer velocities is commonly estimated in terms of Schmidt numbers, i.e. the ratio of kinematic viscosity to diffusivity. In numerical models least square regressions are used to fit the limited number of experimentally derived Schmidt numbers to a function of temperature. For CO2 a well established fit can be found in the literature. This fit constitutes an integral part in standardized carbon cycle simulation projects (e.g. C4MIP, OC4MIP, Friedlingstein et al., 2006 ). However, the fit is valid only in the range where diffusivity measurements exist, i.e., from 0 to about 30 °C. In many climate warming simulations like e.g. the MPI contribution to the fourth Intergovernmental Panel on Climate Change Assessment Report (IPCC AR 4), sea surface temperatures largely exceed the validated range and approach or even reach the range, where the standard fits leave the physically meaningful range. Thus, this paper underlines the demand for new measurements of seawater diffusivities for CO2 and other trace gases especially for the temperature range >30 °C. In this paper we provide improved fits for the temperature dependence of the Schmidt number. For carbon dioxide our fit is compared to the established fit under identical climate change simulations carried out with the 3D-carbon cycle model HAMOCC. We find that in many tropical and subtropical high temperature regions the established fit leads to unrealistically short adaption times of the surface water pCO2 to altered atmospheric pCO2. In regions where the local oceanic pCO2 is not primarily controlled by the atmospheric boundary pCO2 but by other processes such as biological activity, the atmosphere ocean pCO2 gradient is clearly underestimated when using the established fit. The effect on global oceanic carbon uptake in a greenhouse world is rather small and the potential climate feedback introduced by this bias seems to be negligible. However, the bias will clearly gain in significance the more regions warm up to over 30 °C. On a regional scale, especially in coastal regions at low latitudes, the effect is not negligible and a different steady state is approached.

This paper examines the controls on global precipitation that are evident in the transient experiments conducted using coupled climate models collected for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). The change in precipitation, water vapor, clouds, and radiative heating of the atmosphere evident in the 1% increase in carbon dioxide until doubled (1pctto2x) scenario is examined. As noted in other studies, the ensemble-mean changes in water vapor as carbon dioxide is doubled occur at a rate similar to that predicted by the Clausius–Clapeyron relationship. The ratio of global changes in precipitation to global changes in water vapor offers some insight on how readily increased water vapor is converted into precipitation in modeled climate change. This ratio ɛ is introduced in this paper as a gross indicator of the global precipitation efficiency under global warming. The main findings of this paper are threefold. First, increases in the global precipitation track increase atmospheric radiative energy loss and the ratio of precipitation sensitivity to water vapor sensitivity is primarily determined by changes to this atmospheric column energy loss. A reference limit to this ratio is introduced as the rate at which the emission of radiation from the clear-sky atmosphere increases as water vapor increases. It is shown that the derived efficiency based on the simple ratio of precipitation to water vapor sensitivities of models in fact closely matches the sensitivity derived from simple energy balance arguments involving changes to water vapor emission alone. Second, although the rate of increase of clear-sky emission is the dominant factor in the change to the energy balance of the atmosphere, there are two important and offsetting processes that contribute to ɛ in the model simulations studied: One involves a negative feedback through cloud radiative heating that acts to reduce the efficiency; the other is the global reduction in sensible heating that counteracts the effects of the cloud feedback and increases the efficiency. These counteracting feedbacks only apply on the global scale. Third, the negative cloud radiative heating feedback occurs through reductions of cloud amount in the middle troposphere, defined as the layer between 680 and 440 hPa, and by slight global cloud decreases in the lower troposphere. These changes act in a manner to expose the warmer atmosphere below to high clouds, thus resulting in a net warming of the atmospheric column by clouds and a negative feedback on the precipitation.

[1] In the companion to the present paper, the one-dimensional k-e lake model SIMSTRAT is coupled to a single-column atmospheric model, nicknamed FIZC, and an application of the coupled model to the deep Lake Geneva, Switzerland, is described. In this paper, the response of Lake Geneva to global warming caused by an increase in atmospheric carbon dioxide concentration (i.e., 2 × CO2) is investigated. Coupling the models allowed for feedbacks between the lake surface and the atmosphere and produced changes in atmospheric moisture and cloud cover that further modified the downward radiation fluxes. The time evolution of atmospheric variables as well as those of the lake's thermal profile could be reproduced realistically by devising a set of adjustable parameters. In a “control” 1 × CO2 climate experiment, the coupled FIZC-SIMSTRAT model demonstrated genuine skills in reproducing epilimnetic and hypolimnetic temperatures, with annual mean errors and standard deviations of 0.25°C ± 0.25°C and 0.3°C ± 0.15°C, respectively. Doubling the CO2 concentration induced an atmospheric warming that impacted the lake's thermal structure, increasing the stability of the water column and extending the stratified period by 3 weeks. Epilimnetic temperatures were seen to increase by 2.6°C to 4.2°C, while hypolimnion temperatures increased by 2.2°C. Climate change modified components of the surface energy budget through changes mainly in air temperature, moisture, and cloud cover. During summer, reduced cloud cover resulted in an increase in the annual net solar radiation budget. A larger water vapor deficit at the air-water interface induced a cooling effect in the lake.

This paper highlights the global warming of the lower atmosphere of West African tropical area using in-situ data. The study is based on the analysis of 500-m interval vertical profiles of radiosonde temperature above Niamey (13.47°N; 2.16°E) a sub-Saharan meteorological station. The annual cycle of surface temperatures shows seasonally two peaks located in April/May and in October and two minimum in December/January and August respectively. In the mid-troposphere (between 5 km and 10 km height), time series of monthly mean temperatures from January 2001 to December 2018, shows an annual variability with a slight downward trend of -0.036°C per decade. In the lower stratosphere (25 - 30 km altitude) a cooling of -0.64°C/decade is observed. Temperatures time series also highlight the presence of two breaking points associated with the El Nino-Southern Oscillation (ENSO) events. When performing a separation regarding Southern Oscillation Index (SOI) time series, model parameters of the linear regression indicate a tropospheric warming during the neutral and La Nina phases and a stratospheric cooling. The analysis of the lower stratosphere zonal wind highlights different behaviours of the quasi-biennial oscillation (QBO) during the neutral and La Nina phases.

The northwestern Hebei mountains area is located in the transitional area from the subhumid and temperate zone to the semiarid zone, pertaining to the ecologically fragile area. Closing to Beijing and Tianjin, the area is in the windward and upriver area of the two cities. It is of great significance to study the climate change in this area for the purpose of understanding the law of local ecological development and constructing the Beijing-Tianjin ecological protective barrier. Based on the average monthly temperatures and precipitation data collected by three weather stations in the northwestern mountains area between 1956 and 2001, this paper studied the climate changes in this area over the past 46 years, by analyzing the average temperature anomaly and precipitation anomaly of yearly and quarterly, calculating the five years sliding average value of them, and applying the way of univariate linear regression to get linear regression equation of the five years sliding average value. Preliminary research was conducted on the average temperature anomaly and precipitation anomaly values and their development trends with the adoption of correlation analysis. Discussion on factors causing the climate change was carried out. The result shows that the average temperature was on an upward trend in the period 1956-2001 at a rate of 0.41 deg. Celcius /10a, with the highest growth rate seen in winter. In contrast, the annual precipitation was on decrease during the same period at a rate of 7.765mm/10a, with the highest rate seen in summer. The area under research is turning warmer and drier. The correlation analysis indicates no apparent correlation between the upward annual average temperature and the downward precipitation, which should be regarded as a process of independent change. This paper also explores the possible causes that have affected the climate in this area, including the global warming, the climate change in a larger area such as the circulation of water vapor in East Asia as well as the changes to local ecological environment such as pollution, greenhouse gas emissions, increased particulate matters in the atmosphere, ecological damages, etc.

Knowing the onset of snow melt is an important factor in climatological and weather forecasting models. The carbon cycle in the atmosphere is directly related to melting of snow and thus is a key information understanding global climate change. Microwave radiometers are sensitive to liquid water and thus well suited for melt detection. The rather coarse resolution is ideal for monitoring the snow melt globally. However, many snow melt detection algorithms are applicable only on arctic tundra or snow covered glaciers. The authors of this paper have earlier developed melt detection algorithms for boreal forest zone using SSM/I-data. In this paper AMSR-E data is used and the algorithm is slightly modified to operate without using additional data such as ground based measurements. The algorithm is applied over the whole Northern Eurasia and the results obtained are reliable and valuable for further development.

The phenomenon of increasing the temperature of the Earth’s atmosphere over the years is known as the Global warming. The Global warming has several adverse effects on our climate, our health and our communities. The resulting climate changes due to global warming produce significant changes in the weather patterns. It is also argued that the climate changes occurring due to global warming is responsible for the various geological hazards occurring in the world, like earthquakes, volcanic eruptions, tsunamis (Gutenberg and Richter, 1954; Turcotte and Schubert, 2002; Wu and Johnston, 2000; Wu and Hasegawa, 1996a; Wu and Hasegawa, 1996b; Wu, 1997). McGuire in his book (McGuire, 2012) has explained in detail the interlink between the climate changes occurring due to global warming and the occurrence of geological disasters like earthquakes, volcanoes and tsunamis. Looking back to the past, when the climate changed naturally and our planet emerged from the ice age, the huge pressure exerted on the Earth’s crust suddenly disappeared causing the Earth’s crust to bounce back, the increased stress on the Earth’s crust activated earthquakes, tremors and volcanic eruptions along the pre-existing fault lines. Currently, our planet, the Earth is still responding to the end of the last ice age some 20,000 or more years ago when the temperatures began to rise, huge masses of ice-sheets disappeared resulting from the melting of large masses of ice. Thus the rising temperature may be related to the anomalous emanation of soil radon-222 gas prior to an earthquake. The prime focus of this paper is to search for any cross correlation existing between the daily land-surface temperature anomalies and the soil radon concentration using a robust state of art method, Multifractal detrended cross correlation analysis (MF-DXA). The data sets for both the series used for the analysis are for a period from 2005 to 2014. The analysis shows that these two time series are not only cross correlated but having the cross correlation coefficient γ X = 0 . 012 ± 0 . 01 , which clearly indicates a strong correlation between the soil radon-222 anomalies and the daily land-surface temperature anomalies.

Most of the world's permafrost is located in the Arctic, where its frozen organic carbon content makes it a potentially important influence on the global climate system. The Arctic climate appears to be changing more rapidly than the lower latitudes, but observational data density in the region is low. Permafrost thaw and carbon release into the atmosphere, as well as snow cover changes, are positive feedback mechanisms that have the potential for climate warming. It is therefore particularly important to understand the links between the energy balance, which can vary rapidly over hourly to annual timescales, and permafrost conditions, which changes slowly on decadal to centennial timescales. This requires long-term observational data such as that available from the Samoylov research site in northern Siberia, where meteorological parameters, energy balance, and subsurface observations have been recorded since 1998. This paper presents the temporal data set produced between 2002 and 2017, explaining the instrumentation, calibration, processing, and data quality control. Furthermore, we present a merged data set of the parameters, which were measured from 1998 onwards. Additional data include a high-resolution digital terrain model (DTM) obtained from terrestrial lidar laser scanning. Since the data provide observations of temporally variable parameters that influence energy fluxes between permafrost, active-layer soils, and the atmosphere (such as snow depth and soil moisture content), they are suitable for calibrating and quantifying the dynamics of permafrost as a component in earth system models. The data also include soil properties beneath different microtopographic features (a polygon centre, a rim, a slope, and a trough), yielding much-needed information on landscape heterogeneity for use in land surface modelling. For the record from 1998 to 2017, the average mean annual air temperature was −12.3 ∘C, with mean monthly temperature of the warmest month (July) recorded as 9.5 ∘C and for the coldest month (February) −32.7 ∘C. The average annual rainfall was 169 mm. The depth of zero annual amplitude is at 20.75 m. At this depth, the temperature has increased from −9.1 ∘C in 2006 to −7.7 ∘C in 2017. The presented data are freely available through the PANGAEA (https://doi.org/10.1594/PANGAEA.891142) and Zenodo (https://zenodo.org/record/2223709, last access: 6 February 2019) websites.

An important challenge for climate science is to understand the regional circulation and rainfall response to global warming. Unfortunately, the climate models used to project future changes struggle to represent present-day rainfall and circulation, especially at a regional scale. This is the case in southern Africa, where models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) overestimate summer rainfall by as much as 300% compared to observations and tend to underestimate rainfall in Madagascar and the southwest Indian Ocean. In this paper, we explore the climate processes associated with the rainfall bias, with the aim of assessing the reliability of the CMIP5 ensemble and highlighting important areas for model development. We find that the high precipitation rates in models that are wet over southern Africa are associated with an anomalous northeasterly moisture transport (~10–30 g kg−1 s−1) that penetrates across the high topography of Tanzania and Malawi and into subtropical southern Africa. This transport occurs in preference to a southeasterly recurvature toward Madagascar that is seen in drier models and reanalysis data. We demonstrate that topographically related model biases in low-level flow are important for explaining the intermodel spread in rainfall; wetter models have a reduced tendency to block the oncoming northeasterly flow compared to dry models. The differences in low-level flow among models are related to upstream wind speed and model representation of topography, both of which should be foci for model development.

Svante August Arrhenius was the first to calculate global climate sensitivity to changes in atmospheric CO2 concentration. He was also the first to calculate the anthropogenic rate of CO2 buildup in the modern atmosphere. There is apparently an inconsistency, however, between the references to these estimates [e.g., Uppenbrink, 1996] and the real numbers Arrhenius derived in his later works. The citations of Arrhenius' calculations are usually based on the work published in 1896 [Arrhenius, 1896]. In this paper Arrhenius reported that CO2 doubling should increase the Earth's mean temperature by 5–6°C. In the same ear, he estimated that it would take about 3000 y ears for mankind to double the atmospheric concentration through the burning of fossil fuels [Arrhenius, 1896]. However, the 1896 paper was not his last publication on the problem of global warming.

The Caribbean, along with other small island developing states (SIDS), have advocated for restricting global warming to 1.5 °C above pre-industrial levels by the end of the current century. Solar radiation management (SRM) may be one way to achieve this goal. This paper examines the mean Caribbean climate under various scenarios of an SRM-altered versus an SRM-unaltered world for three global warming targets, namely, 1.5, 2.0 and 2.5 °C above pre-industrial levels. Data from the Geoengineering Model Intercomparison Project Phase 1 (GeoMIP1) were examined for two SRM scenarios: the G3 experiment where there is a gradual injection of sulfur dioxide (SO2) into the tropical lower stratosphere starting in 2020 and terminating after 50 years, and the G4 experiment where a fixed 5 Teragram (Tg) of SO2 per year is injected into the atmosphere starting in 2020 and ending after 50 years. The results show that SRM has the potential to delay attainment of the 1.5, 2.0 and 2.5 °C global warming targets. The extent of the delay varies depending on the SRM methodology but may be beyond mid-century for the 1.5 °C goal. In comparison, however, the higher temperature thresholds are both still attained before the end of century once SRM is ceased, raising questions about the value of the initial delay. The application of SRM also significantly alters mean Caribbean climate during the global warming target years (determined for a representative concentration pathway 4.5 (RCP4.5) world without SRM). The Caribbean is generally cooler but drier during the 1.5 °C years and similarly cool but less dry for years corresponding to the higher temperature targets. Finally, the mean Caribbean climate at 1.5 °C differs if the global warming target is achieved under SRM versus RCP4.5. The same is true for the higher warming targets. The implications of all the results are discussed as a background for determining whether SRM represents a viable consideration for Caribbean SIDS to achieve their “1.5 to stay alive” goal.

The Qinghai-Tibetan Plateau (QTP) snow cover information acquisition of the high precision spatial and temporal characteristics is of great significance for the research on its land surface atmosphere coupled system and global climate change effects. The Moderate Resolution Imaging Spectro-radiometer (MODIS) daily snow cover products (MOD10A1 and MYD10A1) have been widely used in long time series of spatial and temporal variation analysis, but they are limited to be used because of high cloud cover ratio. In this paper, a 7-day rolling combination algorithm was presented to eliminate cloud obscuration, and the whole cloud amount falls below 7 %. The ground station in situ measurements verify that the overall precision is more than 90 %. The presented algorithm guaranteed the same spatial resolution and temporal resolution, and has higher precision than products MOD10A1 and MYD10A1. The MODIS 7-day rolling combination snow cover datasets products were obtained between 2003 and 2014 in the QTP, and the snow cover area of spatial and temporal variation was analyzed. The change characteristics of snow cover duration was also studied combining with the Digital Elevation Model data. Results show that the snow cover area of the whole QTP has a slowly decreased trend, but increases in autumn. Thus, the snow cover proportion of annual periodic and unstable in different elevations has the highest correlation with area of the elevation.

We discuss several aspects of the phenomenon called Global Warming and refrain from any con- clusions. We leave the reader to draw his conclusions about the series of observations presented here. The phenomenon called Global Warming or in the new name Climate Change, refers to the be- havior of the ’Temperature of the Earth’ as a function of time. The ’temperature of the Earth’ is a complicated term as it is measured in different locations and one has to define at what location we discuss the temperature and how we average the temperature over the complicated surface of the Earth so as to obtain a single number. The atmosphere, or better said the troposphere, can be considered as a boundary layer. However, this layer is not isothermal and shows large temporal and location temperature variations. There are three basic questions the data should point to: • How the "Global Temperature" of the Earth is evaluated and how the statistical mean be- haves as a function of time, • How the temperature varies at a given fixed location, T(t), • What is the role of CO2 in driving the "Global Earth temperature". We examine in the paper the following topics: • The Global Earth Temperature and Definition of the Temperature Anomaly, • The rise of the oceans, • The behavior of the CO2, • The acidity of the seas, • Underwater volcanos, • The dependence of T(t) for a single place, • Theoretical predictions of the Global Temperature, • The Interaction of the Sun with Earth’s climate, • The phenomenon called ’Global Warming Pause. in an attempt to provide a comprehensive answer to the above questions.

Just over 40 years ago, I wrote a paper entitled “Climate change: Are we on the brink of a pronounced global warming?” In it, I attempted to explain why despite a rise in the atmosphere’s CO2 content there had been no significant warming. I predicted that a natural cooling was about to give way to a warming, and that industrial emissions of CO2 would amplify this warming. The paper published in Science in 1975. Warming did follow in 1976–1977. However, a retrospective look shows that my analysis was flawed. What is more—and to my chagrin—based on the words “global warming” in my Science paper, I was given the title “Father of Global Warming.” Not only did I not like this title, I had done little to merit it.

Problems associated with the effect of climatic and hydrologic characteristics (temperature, precipitation, river run-off) within the Russian landmass and prediction of the performance of water-power entities under these conditions are examined. At the present time, the world's scientific community is of the common opinion that climate changes are occurring on Earth. In a paper presented by the Russian Hydrometeorolo- gic Institute (1), it is noted that "comparison of model calcu- lations with data derived from observations of the tempera- ture of the air in the near-earth atmosphere yields convincing arguments in favor of the anthropogenic nature of global warming, whereby the effect of anthropogenic activity on the temperature of the air is manifested not only in global changes, but also on a continental scale." A large part of the Russian landmass f alls within a region of significant observ- able warming. During the period from 1976 through 2006, the increase in mean annual air temperature with respect to Russia on the whole was 1.33°C for the 31 years, i.e., ex- ceeded the average warming for a 100-year period, which had ranged from 1.00 to 1.29°C. Figure 1 shows the dynam- ics of the variation in mean annual air temperature in Russia during the 20th century. It is apparent from the plot that a particularly rapid increase in temperature was observed in the past 30 - 35 years Global warming of the climate may create, and has al- ready created serious economic, political, and social prob- lems both for Russia, and also for many countries of the world. It should be pointed out that in a zone of global warm- ing, the range of temperature fluctuations also increases. Values of both extremal low, and also extremal high tempera- tures are increasing. The wind regime and moisture regime are becoming more extremal in individual regions.

Models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) robustly predict that the rate of increase in global-mean precipitation with global-mean surface temperature increase is much less than the rate of increase of water vapor. The goal of this paper is to explain in detail the mechanisms by which precipitation increase is constrained by radiative cooling. Changes in clear-sky atmospheric radiative cooling resulting from changes in temperature and humidity in global warming simulations are in good agreement with the multimodel, global-mean precipitation increase projected by GCMs (~1.1 W m−2 K−1). In an atmosphere with fixed specific humidity, radiative cooling from the top of the atmosphere (TOA) increases in response to a uniform temperature increase of the surface and atmosphere, while atmospheric cooling by exchange with the surface decreases because the upward emission of longwave radiation from the surface increases more than the downward longwave radiation from the atmosphere. When a fixed relative humidity (RH) assumption is made, however, uniform warming causes a much smaller increase of cooling at the TOA, and the surface contribution reverses to an increase in net cooling rate due to increased downward emission from water vapor. Sensitivity of precipitation changes to lapse rate changes is modest when RH is fixed. Carbon dioxide reduces TOA emission with only weak effects on surface fluxes, and thus suppresses precipitation. The net atmospheric cooling response and thereby the precipitation response to CO2-induced warming at fixed RH are mostly contributed by changes in surface fluxes. The role of clouds is discussed. Intermodel spread in the rate of precipitation increase across the CMIP5 simulations is attributed to differences in the atmospheric cooling.

Global warming is a major concern nowadays. Weather conditions are changing, and it seems that human activity is one of the main causes. In fact, since the beginning of the industrial revolution, the burning of fossil fuels has increased the nonnatural emissions of carbon dioxide to the atmosphere. Carbon dioxide is a greenhouse gas that absorbs the infrared radiation produced by the reflection of the sunlight on the Earth’s surface, trapping the heat in the atmosphere. Global warming and the associated climate changes are being the subject of intensive research due to their major impact on social, economic, and health aspects of human life. This paper studies the global warming trend in the perspective of dynamical systems and fractional calculus, which is a new standpoint in this context. Worldwide distributed meteorological stations and temperature records for the last 100 years are analysed. It is shown that the application of Fourier transforms and power law trend lines leads to an assertive representation of the global warming dynamics and a simpler analysis of its characteristics.

In a recent comment on the paper by Aronson and McNulty (2009) about “Appropriate experimental ecosystem warming methods by ecosystem, objective, and practicality”, Amthor et al. (2010) state that infrared lamps do not warm open-field plots by the mechanism expected with global warming. While this statement is correct, in the aftermath of their comment, confusion exists about how warming with infrared heaters can be related to global warming. This comment illustrates how infrared heating at “constant temperature rise” relates in a quantitative way to anticipated global warming. Amthor et al. (2010) also state that changes in vapor pressure gradient from leaf to atmosphere are an issue with infrared heating, but this problem can be minimized with supplemental irrigations in controlled amounts. Therefore, “constant temperature rise” infrared warming experiments with supplemental irrigations are a viable T-FACE (temperature free-air controlled enhancement) that can be used in combination with CO2-FACE to produce conditions more representative of future open-fields than can be done with chambers with their many known artifacts.

This paper is devoted to a brief critical review of major achievements and shortcomings in numerical modeling of climatic characteristics of the World Ocean. It is shown that the most interesting results are obtained due to the transition to high resolution (the horizontal grid spacing being no more than 1/18°). The need to switch to higher resolution (about 0.01°) is also obvious. The author deeply appreciates the study by Guo et al. [25] in which the role of JEBAR and other terms of the integral mass transport equation is assessed. High resolution, however, is not the only problem. A mathematical description of the physical processes of ice formation and melting and a four-dimensional analysis of the data remain a difficult problem. It is noted that in a number of studies extensive integration tends to filter out the results in a simulation of intense currents. This process of Sverdrupization of the integral mass transport is shown schematically in Fig. 2. An original scheme of the formation of the equatorial subsurface countercurrents is presented. The author suggests that neither modeling nor analyzing the resulting data show the presence of warming in the World Ocean; hence, there is no global warming in the atmosphere either.

A much-cited bar chart provided by the Intergovernmental Panel on Climate Change displays the climate impact, as expressed by radiative forcing in watts per meter squared, of individual chemical species. The organization of the chart reflects the history of atmospheric chemistry, in which investigators typically focused on a single species of interest. However, changes in pollutant emissions and concentrations are a symptom, not a cause , of the primary driver of anthropogenic climate change: human activity. In this paper, we suggest organizing the bar chart according to drivers of change—that is, by economic sector. Climate impacts of tropospheric ozone, fine aerosols, aerosol-cloud interactions, methane, and long-lived greenhouse gases are considered. We quantify the future evolution of the total radiative forcing due to perpetual constant year 2000 emissions by sector, most relevant for the development of climate policy now, and focus on two specific time points, near-term at 2020 and long-term at 2100. Because sector profiles differ greatly, this approach fosters the development of smart climate policy and is useful to identify effective opportunities for rapid mitigation of anthropogenic radiative forcing.

This paper analyzes trends of temperatures over Africa and seeks to quantify the most significant processes. Observations of air temperature reveal significant warming trends in the 925–600 hPa layer over tropical west Africa and the east Atlantic. This is related to the influence of desert dust and biomass burning emissions on the atmospheric energy budget. We calculate a net radiative absorption of ∼− 20 W m − 2. The southern (northern) plume is rich in short-lived greenhouse gases (dust aerosols), and the atmospheric response, according to a simplified radiative transfer model, is a >3°C heating of the 2–4 km layer. The observed pattern of warming coincides with a mixture of dust, black carbon and short-lived greenhouse gases in space, time and height. Physical forcing provides a secondary source of regional warming, with sinking motions over the Sahel. The elevated warm layer stabilizes the lower atmosphere over and west of Africa, so drying trends may be anticipated.

The ponding of cold air at low elevations is a major feature of the high-latitude climates of the Arctic, wherever low solar angles combine with incised topography. In Finnish Lapland this cold-air accumulation is critical for flora and fauna (Tenow and Nilssen, 1990; Virtanen et al., 1998) since absolute minimum temperatures control the survival of the eggs of the autumnal moth Epirrita autumnata. This moth is responsible for outbreaks of defoliation of the mountain birch Betula pubescens. Without cold-air accumulation there would be far more destructive outbreaks in the main inhabited areas. Added to the above concern is that of global warming. Warming is expected to be greater than the global average in the high latitudes (IPCC, 2007) and the temperature rise in winter in Finland over the twenty-first century is expected to be particularly large (Jylha et al., 2004). Current predictions made by the Intergovernmental Panel on Climate Change (IPCC) (2007) indicate a best estimate annual warming of around +5 degC for northern Finland by 2099 (~+7 degC in winter), as opposed to +3.2 degC for Europe as a whole (A1B scenario). If the enhancement of greenhouse gases in the atmosphere also alters the propensity for cold-pool formation, local increases in winter temperatures could be even more dramatic than the regional mean, with large consequences for forest damage, local ecology, and the formation/destruction of lake ice in autumn and spring. The cold pool is transient and its formation and destruction are controlled by synoptic conditions (atmospheric gradient winds and cloud cover/radiation balance) as well as the interaction with local topography. The research summarized in this paper comes from a pilot study which aimed to quantify the existence, temporal and spatial extent of the cold pool in Kevo Valley, northern Finland, through operation of an elevationaltransect of automatic temperature loggers.Future research is mapping the spatial extent of this cold pool in more detail, and examining the mechanisms behind its formation and destruction.

A revisit on observations shows that the tropical El Niño–Southern Oscillation (ENSO) variability, after removing both the long-term trend and decadal variation of the background climate, has been enhanced by as much as 50% during the past 50 yr. This is inconsistent with the changes in the equatorial atmosphere, which shows a slowdown of the zonal Walker circulation and tends to stabilize the tropical coupling system. The ocean role is highlighted in this paper. The enhanced ENSO variability is attributed to the strengthened equatorial thermocline that acts as a destabilizing factor of the tropical coupling system. To quantify the dynamic effect of the ocean on the ENSO variability under the global warming, ensemble experiments are performed using a coupled climate model [Fast Ocean Atmosphere Model (FOAM)], following the “1pctto2x” scenario defined in the Intergovernmental Panel on Climate Change (IPCC) reports. Term balance analyses on the temperature variability equation show that the anomalous upwelling of the mean vertical temperature gradient (referred as the “local term”) in the eastern equatorial Pacific is the most important destabilizing factor to the temperature variabilities. The magnitude of local term and its change are controlled by its two components: the mean vertical temperature gradient Tz and the “virtual vertical heat flux” −w′T ′. The former can be viewed as the background of the latter and these two components are positively correlated. A stronger Tz is usually associated with a bigger upward heat flux −w′T ′, which implies a bigger impact of thermocline depth variations on SST. The Tz is first enhanced during the transient stage of the global warming with a 1% yr−1 increase of CO2, and then reduced during the equilibrium stage with a fixed doubled CO2. This turnaround in Tz determines the turnaround of ENSO variability in the entire global warming period.

This paper examines several prominent thermodynamic and dynamic factors responsible for the meridional and vertical warming asymmetries using a moist coupled atmosphere–surface radiative transportive four-box climate model. A coupled atmosphere–surface feedback analysis is formulated to isolate the direct response to an anthropogenic greenhouse gas forcing from individual local feedbacks (water vapor, evaporation, surface sensible heat flux, and ice-albedo), and from the non-local dynamical feedback. Both the direct response and response to water vapor feedback are stronger in low latitudes. The joint effect of the ice-albedo and dynamical greenhouse-plus feedbacks acts to amplify the high latitude surface warming whereas both the evaporation and dynamical greenhouse-minus feedbacks cause a reduction of the surface warming in low latitudes. The enhancement (reduction) of local feedbacks in high (low) latitudes in response to the non-local dynamic feedback further strengthens the polar amplification of the surface warming. Both the direct response and response to water vapor feedback lead to an increase of lapse rate in both low and high latitudes. The stronger total dynamic heating in the mean state in high latitudes is responsible for a larger increase of lapse rate in high latitudes in the direct response and response to water vapor feedback. The local evaporation and surface sensible heat flux feedbacks reduce the lapse rate both in low and high latitudes through cooling the surface and warming the atmosphere. The much stronger evaporation feedback leads to a final warming in low latitudes that is stronger in the atmosphere than the surface.

Research on factors of climate variations on a seasonal to multi-decadal timescale is surveyed. However, it is difficult to fully cover wide-ranging research on climate systems including the latest results. This paper focuses on phenomena such as QBO that interact with the other factors. Oceans, which have a clqse relationship with climate change, are considered. Although there is overlapping with dissertations in another chapter, the main contents are as follows: 1) ENSO is a quasi-periodic air-sea interaction, which has been studied closely. If evolvement of ENSO is predicted, it will make seasonal weather forecasts more precise. 2) The effects of stratospheric QBO on climate systems in the troposphere might have been exercised as grave cool damage that occurs in summers when QBO was in the W-phase, and some correlations have been found. QBO probably holds a significant key explaining climate variations. Therefore, elucidation of the QBO mechanism that influences the troposphere can be expected. 3) The relationship between solar activities and climate remains obscure. However, some influences of solar activities on the tropospheric circulation have been felt through sea surface temperature or interaction with stratospheric QBO. 4) In the air-sea interaction the ocean responds to solar radiation more slowly than the atmosphere, so the ocean seems to play a dominant role in long-lived teleconnections such as PDO. In addition, regime shifts of oceans sometimes have major effects on climate. We cannot discuss climate change without referring to oceans. 5) Global warming is in progress. As a result, shifts in general circulation might lead to abnormal weather, which means increased danger of frequent developments of the Okhotsk high, which is responsible for cool summer damage. 6) It is important to evaluate which factors contribute greatly to climate change. Understanding the mechanisms of weather fluctuations ranging from a few months to several years is a pressing matter to prevent recurrence of meteorological disasters.

The existence of an ice cover has important effects on the streamflow conditions as well as on the heat transfer between water bodies and the overlying atmosphere. This paper investigates the effects of climate variability on the termination of the ice season in the Baltic region. In particular, trends and fluctuations observed in the cryophenological records from this region are analyzed in detail, searching for possible connections with the North Atlantic Oscillation (NAO). The NAO seems to affect mostly the late-winter temperature (January–March) with a significant impact also on the mid-spring (April–May) period, when the air temperature is strongly correlated to the ice dates. A regional analysis shows the existence in the series of winter temperature (JFM) of the same fluctuations as the winter NAO. The same components can be found in the cryophenological records and (partly) in the series of spring temperature. Nevertheless, both ice phenology and spring temperature show the existence of a very well defined trend that is not detectable in the series of winter NAO at time scales of a century or longer. This leads to the conclusion that winter NAO has still a weak, though significant, effect on the regime of spring temperature in the Baltic region and explains the most significant fluctuating components embedded in the cryophenological records. However it is argued that other climatic forcings, related to CO 2 -induced regional and global warming, acting at the end of the ice season, are able to induce pronounced trends in the regime of spring temperature and have an important impact on the cryosphere leading to the earlier occurrence of ice break-up observed in the last several decades.

This paper seeks to assess if there is any evidence that Chlorofluorocarbons (CFCs) have caused global warming during 1969 to 1998. The choice of the period of study is driven by the historical fact that the accumulation of CFCs in the atmosphere increased during this phase and the global temperature also registered steady increases. By exploiting a data set on accumulated CFCs along with changes in the global temperature we bring two new insights to the literature on global warming and CFCs: first and foremost, we introduce an Autoregressive Distributed Lagged (ARDL) model to capture the long-term relationship between CFCs and global warming. By doing this we establish that a statistically significant long-run relationship exists between CFCs and global warming. Secondly, we also establish that the nature of this relationship is rather counter-intuitive: the growth in the concentration of CFCs in the atmosphere, as our study finds, has reduced the increases in the global temperature during 1969 -1998. There is thus little empirical support that the CFCs are a source of global warming.

The aim of this paper is to report on the development of regional climate change scenarios for Kazakhstan as the result of increasing of CO2 concentration in the global atmosphere. These scenarios are used in the assessment of climate change impacts on the agricultural, forest and water resources of Kazakhstan. Climate change scenarios for Kazakhstan to assess both long-term (2× CO2 in 2075) and short-term (2000, 2010 and 2030) impacts were prepared. The climate conditions under increasing CO2 concentration were estimated from three General Circulation Models (GCM) outputs: the model of the Canadian Climate Center Model (CCCM), the model of the Geophysical Fluid Dynamics Laboratory (GFDL) and the 1% transient version of the GFDL model (GFDL-T). The near-term climate scenarios were obtained using the probabilistic forecast model (PFM) to the year 2010 and the results of GFDL-T for years 2000 and 2030. A baseline scenario representing the current climate conditions based on observations from 1951 to 1980 was developed. The assessment of climate change in Kazakhstan based on the analysis of 100-years observations is given too. As a result of comparisons of the current climate (based on observed climate) the 1× CO2 output from GCMs showed that the GFDL model best matches the observed climate. The GFDL model suggests that the minimum increase in temperature is expected in winter, when most of the territory is expected to have temperatures 2.3–4.5 °C higher. The maximum (4.3 to 8.2 °C) is expected to be in spring. CCCM scenario estimates an extreme worming above 11 °C in spring months. GFDL-T outputs provide an ‘intermediate’ scenario.

This paper presents the first basin-wide assessment of the potential impact of climate change on the hydrology and production of the Ganges system, undertaken as part of the World Bank’s Ganges Strategic Basin Assessment. A series of modeling efforts, downscaling of climate projections, water balance calculations, hydrological simulation and economic optimization, inform the assessment. The authors find that projections of precipitation across the basin, obtained from 16 Intergovernmental Panel on Climate Change-recognized General Circulation Models are highly variable, and lead to considerable differences in predictions of mean flows in the main stem of the Ganges and its tributaries. Despite uncertainties in predicted future flows, they are not, however, outside the range of natural variability in this basin, except perhaps at the tributary or sub-catchment levels. The authors also find that the hydropower potential associated with a set of 23 large dams in Nepal remains high across climate models, largely because annual flow in the tributary rivers greatly exceeds the storage capacities of these projects even in dry scenarios. The additional storage and smoothing of flows provided by these infrastructures translates into enhanced water availability in the dry season, but the relative value of this water for the purposes of irrigation in the Gangetic plain, and for low flow augmentation to Bangladesh under climate change, is unclear.

Estimates of the Arctic soil carbon pool have more than doubled in size recently. However, it remains very uncertain how much of this carbon will enter the atmosphere as a result of future global warming. We review in this paper recent estimates of the Arctic soil carbon pool, and experimental and modeling studies. We conclude that the part of the carbon pool that is particularly vulnerable to decomposition at short and long time scales needs better quantification. Current models are insufficiently equipped to quantify the carbon release at rapid thaw of ice-rich permafrost, which also may occur at mean annual air temperatures far below zero. Also the resilience of the carbon sink of ecosystems subject to permafrost thaw needs better quantification. © 2012 Elsevier B.V.

Permafrost is considered to be one of the most vulnerable carbon pools, which might lose massive amounts of carbon to the atmosphere in a warming climate, thus further accelerating climate warming (e.g. Davidson and Janssens, 2006; Zimov et al., 2006). Khvorostyanov et al. (2008a,b,c) recently presented simulations of the development of the permafrost carbon cycle in response to climate warming based on a deterministic numerical model, which accounts for heat and gas transport in the soil column as well as for the metabolic heat release during microbial organic matter decomposition. These simulations suggest rapid and deep permafrost thawing in response to a transient climate warming accelerated by a ‘self-sustaining’ positive feedback between thawing and heat release by microbial decomposition of the thawed organic matter. However, the simulation results and the corresponding conclusions appear questionable due to the application of an unjustifiable model boundary condition. The problematic boundary condition is given in eq. (3) in the paper of Khvorostyanov et al. (2008a) as. DOI: 10.1111/j.1600-0889.2009.00419.x

Global warming in the troposphere and the decrease of stratospheric ozone concentration has become a major concern to the scientific community. The increase in greenhouse gases and aerosols concentration is believed to be the main cause of this global change in the lower atmosphere and in stratospheric ozone, which is corresponded by a cooling in the middle and upper atmosphere. However, there are natural sources, such as the sun and volcanic eruptions, with the same ability to produce global changes in the atmosphere. The present work will focus on solar variation and its signature in lower and middle atmosphere parameters. The Sun can influence the Earth and its climate through electromagnetic radiation variations and also through changes in the solar wind which causes geomagnetic storms. The effects of both mechanisms over the lower and middle atmosphere and ozone layer will be discussed through an overview of selected papers, which by no means cover this subject that is extremely wide and complex. A fundamental understanding of the atmosphere response to solar variations is required for understanding and interpreting the causes of atmospheric variability. This is an essential focus of climate science, which is seeking to determine the extent to which human activities are altering the planetary energy balance through the emission of greenhouse gases and pollutants. Fil: Elias, Ana Georgina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina