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Climate change is a critical issue of our time, and its causes, pathways, and forecasts remain a topic of broader discussion. In this paper, we present a novel data driven pathway analysis framework to identify the key processes behind mean global temperature and sea level rise, and to forecast the magnitude of their increase from the present to 2100. Based on historical data and dynamic statistical modeling alone, we have established the causal pathways that connect increasing greenhouse gas emissions to increasing global mean temperature and sea level, with its intermediate links encompassing humidity, sea ice coverage, and glacier mass, but not for sunspot numbers. Our results indicate that if no action is taken to curb anthropogenic greenhouse gas emissions, the global average temperature would rise to an estimated 3.28 °C (2.46–4.10 °C) above its pre-industrial level while the global sea level would be an estimated 573 mm (474–671 mm) above its 2021 mean by 2100. However, if countries adhere to the greenhouse gas emission regulations outlined in the 2021 United Nations Conference on Climate Change (COP26), the rise in global temperature would lessen to an average increase of 1.88 °C (1.43–2.33 °C) above its pre-industrial level, albeit still higher than the targeted 1.5 °C, while the sea level increase would reduce to 449 mm (389–509 mm) above its 2021 mean by 2100. [ABSTRACT FROM AUTHOR]

Many regions around the world are facing climate changes, with substantial increase in air temperature over the past decades, which is mainly related to continental and global warming forced by the higher greenhouse gas (GHG) emissions. The objectives of this study were to use the Köppen climate classification to detect local climate change based on a historical series of 100 years and to assess if such change is related to those that are occurring in other spatial scales as a likely consequence of increasing GHG. This paper brings a content full of innovative results. The study area presented an average annual air temperature increase by 0.9 °C between 1917 and 2016, rising from 21.4 °C for the first climatological normal (1917–1946) to 22.3 °C for the last one (1987–2016). Furthermore, in the summer months, the temperature rose from 24.5 to 25.3 °C, and in the winter months, such increase was from 17.1 (1917–1946) to 18.3 °C (1987–2016). Our findings showed the subtropical conditions (Cfa in Köppen's classification) in the study area persisted from the beginning of the analysis (1917–1946) until the climatological normal of 1979–2008, with a clear tendency of tropicalization after that with a change in the climate type of Piracicaba from subtropical to tropical, which can now be classified as tropical with dry winter (Aw climate type). The local average air temperature showed concordances with the long-term air temperature anomalies from regional, continental, and global scales, indicating that all of them may be linked with increasing GHG emissions, since well-defined long-term linear relationships (r2 = 0.99) were observed between continental and global average air temperature anomalies and atmospheric CO2 concentration observed at the NOAA Lab in Mauna Loa in the last 59 years. While the local and regional forcing effects remain to be fully unraveled, our study provided a valid and strong scientific sound evidence that climate change occurred in Piracicaba, southeastern Brazil, in the last 100 years. [ABSTRACT FROM AUTHOR]

Global Warming Potential (GWP) is an index used to measure the cumulative radiative forcing of a tonne of greenhouse house gas (GHG) relative to that of a ‘reference’ gas (CO2). Under the Kyoto Protocol, GWP can be used as a fixed index to govern the trade-off between different GHGs in a multi-gas approach to GHGs abatement. The use of fixed GWPs has been criticized for not being very cost effective compared to the use of some flexible indices. To gain wider acceptance, however, a flexible index must also prove to be easy to use, and the economic gains from its adoption must be significant. In this paper, we develop a flexible index based on the concept of marginal rather than cumulative or average global warming potentials. These marginal global warming potentials (MGWPs) can be endogenously determined within a climate model given a particular climate objective based on radiative forcing level. The MGPWs are then linked to the marginal abatement costs of the GHGs, which are also endogenously determined within an economic model. When the two concepts are linked in this way, the result is a cost-effective way of achieving a particular climate change objective with multigas abatement. We show that the savings in costs when using this flexible MGPWs can be significant, and more importantly, they are not uniformly distributed across different regions. [ABSTRACT FROM AUTHOR]

Excessive concentration of greenhouse gases in atmosphere emitted from human activities has been considerably changing the world's climate, especially in the last 50 years. Agriculture, as humans' food production system, has undoubtedly interrelated with climate change (CC). During current decades, the impacts of CC on agriculture have been properly investigated; however, the impacts of agriculture on CC have received lower attention. This may be due to the scarcity of long-term spatiotemporal climatic and agricultural data to analyze coupling trends and interactions. Benefiting from a comprehensive database and using structural equation modeling, this study seeks to investigate the contribution of agriculture to CC in Iran for more than half a century. For this, two indicators were developed to evaluate structural characteristics of agricultural expansion (AEI) and CC at the province level. Then, the effect of AEI on CC was investigated using the structural equation modeling technique. The results showed that AEI has not had a positive contribution to raising the long-term average surface temperature. Precisely, the provinces with a higher level of surface temperature have had a lower AEI, indicating that other sectors outweigh agriculture in exacerbating long-term CC in the country. Nevertheless, Iran still needs to improve and sustain its agricultural practices and technologies. The main conclusion of this study is that if the government and policymakers aspire to manage CC, they should have a more holistic and systematic view. In other words, not only do they need to consider all drivers of CC, but they also have to pay close attention to the network of relationships among the drivers. [ABSTRACT FROM AUTHOR]

Increasing atmospheric concentrations of greenhouse gases are widely expected to cause global warming and other climatic changes. It is important to establish priorities for reducing greenhouse-gas emissions, so that resources can be allocated efficiently and effectively. This is a global problem, and it is possible, on a global scale, to identify those activities whose emissions have the greatest potential for enhancing the greenhouse effect. However, perspectives from smaller scales must be appreciated, because it is on scales down to the local level that response measures will be implemented. This paper analyzes the relative importance of emissions from the many individual sources, on scales ranging from global to national to subnational. Individual country perspectives and proposed policy measures and those of subnational political entities exhibit some commonalities but differ among themselves and from a global-scale perspective in detail. [ABSTRACT FROM AUTHOR]

Climate change due to greenhouse gas emissions is predicted to raise the mean global temperature by 1.0–3.5°C in the next 50–100 years. The direct and indirect effects of this potential increase in temperature on terrestrial ecosystems and ecosystem processes are likely to be complex and highly varied in time and space. The Global Change and Terrestrial Ecosystems core project of the International Geosphere-Biosphere Programme has recently launched a Network of Ecosystem Warming Studies, the goals of which are to integrate and foster research on ecosystem-level effects of rising temperature. In this paper, we use meta-analysis to synthesize data on the response of soil respiration, net N mineralization, and aboveground plant productivity to experimental ecosystem warming at 32 research sites representing four broadly defined biomes, including high (latitude or altitude) tundra, low tundra, grassland, and forest. Warming methods included electrical heat-resistance ground cables, greenhouses, vented and unvented field chambers, overhead infrared lamps, and passive night-time warming. Although results from individual sites showed considerable variation in response to warming, results from the meta-analysis showed that, across all sites and years, 2–9 years of experimental warming in the range 0.3–6.0°C significantly increased soil respiration rates by 20% (with a 95% confidence interval of 18–22%), net N mineralization rates by 46% (with a 95% confidence interval of 30–64%), and plant productivity by 19% (with a 95% confidence interval of 15–23%). The response of soil respiration to warming was generally larger in forested ecosystems compared to low tundra and grassland ecosystems, and the response of plant productivity was generally larger in low tundra ecosystems than in forest and grassland ecosystems. With the exception of aboveground plant productivity, which showed a greater positive response to warming in colder ecosystems, the magnitude of the response of these three processes to experimental warming was not generally significantly related to the geographic, climatic, or environmental variables evaluated in this analysis. This underscores the need to understand the relative importance of specific factors (such as temperature, moisture, site quality, vegetation type, successional status, land-use history, etc.) at different spatial and temporal scales, and suggests that we should be cautious in "scaling up" responses from the plot and site level to the landscape and biome level. Overall, ecosystem-warming experiments are shown to provide valuable insights on the response of terrestrial ecosystems to elevated temperature. [ABSTRACT FROM AUTHOR]

Copyright of Advances in Atmospheric Sciences is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We analyze stability of self-enforcing climate agreements, considering a sequential coalition formation process of heterogeneous and farsighted players. Players can make proposals which are either accepted or countered by alternative proposals. We discuss the conceptual difficulties of implementing and solving such a game and the strategic options arising in a sequential process. This is illustrated with simple examples and with numerical simulations using the CLIMNEG world simulation model (CWSM). [ABSTRACT FROM AUTHOR]

In a warming climate, permafrost is likely to be significantly reduced and eventually disappear from the sub-Arctic region. This will affect people at a range of scales, from locally by slumping of buildings and roads, to globally as melting of permafrost will most likely increase the emissions of the powerful greenhouse gas methane, which will further enhance global warming. In order to predict future changes in permafrost, it is crucial to understand what determines the presence or absence of permafrost under current climate conditions, to assess where permafrost is particularly vulnerable to climate change, and to identify where changes are already occurring. The Torneträsk region of northern sub-Arctic Sweden is one area where changes in permafrost have been recorded and where permafrost could be particularly vulnerable to any future climate changes. This paper therefore reviews the various physical, biological, and anthropogenic parameters that determine the presence or absence of permafrost in the Torneträsk region under current climate conditions, so that we can gain an understanding of its current vulnerability and potential future responses to climate change. A patchy permafrost distribution as found in the Torneträsk region is not random, but a consequence of site-specific factors that control the microclimate and hence the surface and subsurface temperature. It is also a product of past as well as current processes. In sub-Arctic areas such as northern Sweden, it is mainly the physical parameters, e.g., topography, soil type, and climate (in particular snow depth), that determine permafrost distribution. Even though humans have been present in the study area for centuries, their impacts on permafrost distribution can more or less be neglected at the catchment level. Because ongoing climate warming is projected to continue and lead to an increased snow cover, the permafrost in the region will most likely disappear within decades, at least at lower elevations. [ABSTRACT FROM AUTHOR]

Understanding the drivers of greenhouse gas (GHG) emissions is one of the most critical global environmental challenges to mitigate the increasing global temperature. Nitrous oxide (N2O) emissions are highly variable in space and time and are controlled by multiple proximal drivers, that is, those that affect N2O emissions directly and in short timescales, and distal or indirect drivers that influence emissions over long timescales. Here we present a quantification of N2O emissions in grasslands and forests throughout the Pampas and the Semiarid Chaco in Argentina and reveal distal and proximal drivers, analyzing them in both spatial and temporal models. We measured N2O emissions, soil and climate variables monthly in nine sites over two years. Mean annual temperature and the following soil properties: phosphorous availability, carbon:nitrogen ratio, clay and sand percentages were the main distal drivers controlling N2O emissions in the spatial model, while among proximal drivers, only soil nitrate contents were positively related to N2O emissions. When considering the seasonal variability of N2O emissions (temporal model), we found that emissions were positively related to proximal drivers, such as soil nitrate and soil temperature. Our results show that soil N2O emission drivers differ between spatial and temporal models in natural grasslands and forests, explaining up to 85 and 56% of variations in N2O emissions, respectively. Temperature increased N2O emissions in both spatial and temporal models; therefore, future global warming may increase background emissions from natural ecosystems with important positive feedbacks on the earth system warming. [ABSTRACT FROM AUTHOR]

Climate change and land use conversion are two major global environmental issues. A claim is made that climate change has brought new challenges for global land use, while land use conversion is hardly realized as a major driver for climate change. Using mapping techniques, this study aims to investigate the relationship between climate change and agricultural land conversion (ALC), by which land is converted from agricultural to other uses (e.g., urban areas, national and natural parks, roads, industrial areas, and afforestation projects). CO2 emission is considered as the main impact of climate change, and agricultural land conversion is regarded as the most important global land use. In this study, data are obtained from two databases: the World Bank and the Food and Agriculture Organization (FAO) for the period of 1962–2011. Considering the FAO (2015) classification, the countries are categorized into five different groups (high-income non-OECD, high-income OECD, upper-middle-, lower-middle-, and low-income countries). Economies were divided into several income groups according to 2014 gross national income per capita. The results show that agricultural areas in high-income countries have decreased, while in low- to middle-income countries, they have increased. The highest CO2 emissions can be observed, especially in high-income countries, whereas the lowest CO2 emissions happen in the low- and lower-middle-income countries. The results further show that there is a positive relationship between CO2 emissions and ALC across the world. It can be observed that CO2 emission is increasing where agricultural area is declining. On the contrary, CO2 emission is declining where agricultural area is increasing. [ABSTRACT FROM AUTHOR]

Global warming affects the thermal stratification of freshwater lakes, and thus can lead to thermocline deepening. To follow the direct and indirect effects of thermocline shifts on processes at the sediment-water interface, the thermoclines in six of twelve lake enclosures were deepened by pumping warm surface water below the thermocline. Hypolimnetic temperatures increased and oxygen concentrations decreased due to the treatment. Path modeling suggests a correlation of the treatment to epilimnetic chlorophytes and hypolimnetic diatoms, while the dominant cryptophytes and cyanobacteria remained unaffected by the treatment. Sedimentation rates, ranging between 0.1 and 1.9 g m day per enclosure, correlated strongly with the selected phytoplankton groups, but were not affected by the treatment. Concentrations of elements (Ba, Mn, S, Sr), nutrients (NH , PO , Si), and greenhouse gases (CO, CH, NO) in the upper centimeter of the sediment were not affected by the hypolimnetic changes. Methane and carbon dioxide emission from the enclosures to the atmosphere were negligible. Bacterial and viral abundance in sediments were not affected by the treatment. Results suggest that the benthic ecosystem remains unaffected by slight changes in the pelagial. Further, we conclude that short-term warming does not increase greenhouse gas emissions from temperate, deep, oligo-mesotrophic lakes. [ABSTRACT FROM AUTHOR]

Copyright of Advances in Atmospheric Sciences is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Boreal fires can cool the climate; however, this conclusion came from individual fires and may not represent the whole story. We hypothesize that the climatic impact of boreal fires depends on local landscape heterogeneity such as burn severity, prefire vegetation type, and soil properties. To test this hypothesis, spatially explicit emission of greenhouse gases (GHGs) and aerosols and their resulting radiative forcing are required as an important and necessary component towards a full assessment. In this study, we integrated remote sensing (Landsat and MODIS) and models (carbon consumption model, emission factors model, and radiative forcing model) to calculate the carbon consumption, GHGs and aerosol emissions, and their radiative forcing of 2001-2010 fires at 30 m resolution in the Yukon River Basin of Alaska. Total carbon consumption showed significant spatial variation, with a mean of 2,615 g C m and a standard deviation of 2,589 g C m. The carbon consumption led to different amounts of GHGs and aerosol emissions, ranging from 593.26 Tg (CO) to 0.16 Tg (NO). When converted to equivalent CO based on global warming potential metric, the maximum 20 years equivalent CO was black carbon (713.77 Tg), and the lowest 20 years equivalent CO was organic carbon (−583.13 Tg). The resulting radiative forcing also showed significant spatial variation: CO, CH, and NO can cause a 20-year mean radiative forcing of 7.41 W m with a standard deviation of 2.87 W m. This emission forcing heterogeneity indicates that different boreal fires have different climatic impacts. When considering the spatial variation of other forcings, such as surface shortwave forcing, we may conclude that some boreal fires, especially boreal deciduous fires, can warm the climate. [ABSTRACT FROM AUTHOR]

Substantial progress has been made over the past three decades since the Monsoon Experiments (MONEX) of 1978-79. Here, we review these achievements by highlighting four breakthroughs in monsoon research: (1) The identification of the coupled ocean-land-atmosphere nature of the monsoon in the process of the annual cycle of solar heating; (2) new understanding of the changes in the driving forces of monsoon systems, with anthropogenic factors (climate effects of increased greenhouse gas and aerosol emissions) playing an important role in the regulation of monsoons; (3) detection of the interdecadal- and centennial-scale variability of monsoon systems, and its attribution to the combined impact of global warming and natural (especially oceanic) effects; and (4) the emerging concept of the global monsoon and its long-term variation under the impact of global climate change. All the observational and model-derived evidence demonstrates that the monsoon system, as an important component of the global climate system, has already changed and will continue to change in the future. This picture of an evolving monsoon system poses great challenges for near-term prediction and long-term projection. [ABSTRACT FROM AUTHOR]

During ice-age cycles, continental ice volume kept pace with slow, multi-millennial scale, changes in climate forcing. Today, rapid greenhouse gas (GHG) increases have outpaced ice-volume responses, likely committing us to > 9 m of long-term sea-level rise (SLR). We portray a context of naturally precedented SLR from geological evidence, for comparison with historical observations and future projections. This context supports SLR of up to 0.9 (1.8) m by 2100 and 2.7 (5.0) m by 2200, relative to 2000, at 68% (95%) probability. Historical SLR observations and glaciological assessments track the upper 68% limit. Hence, modern change is rapid by past interglacial standards but within the range of 'normal' processes. The upper 95% limit offers a useful low probability/high risk value. Exceedance would require conditions without natural interglacial precedents, such as catastrophic ice-sheet collapse, or activation of major East Antarctic mass loss at sustained CO2 levels above 1000 ppmv. [ABSTRACT FROM AUTHOR]

Evidence from Greenland ice cores shows that year-to-year temperature variability was probably higher in some past cold periods, but there is considerable interest in determining whether global warming is increasing climate variability at present. This interest is motivated by an understanding that increased variability and resulting extreme weather conditions may be more difficult for society to adapt to than altered mean conditions. So far, however, in spite of suggestions of increased variability, there is considerable uncertainty as to whether it is occurring. Here we show that although fluctuations in annual temperature have indeed shown substantial geographical variation over the past few decades, the time-evolving standard deviation of globally averaged temperature anomalies has been stable. A feature of the changes has been a tendency for many regions of low variability to experience increases, which might contribute to the perception of increased climate volatility. The normalization of temperature anomalies creates the impression of larger relative overall increases, but our use of absolute values, which we argue is a more appropriate approach, reveals little change. Regionally, greater year-to-year changes recently occurred in much of North America and Europe. Many climate models predict that total variability will ultimately decrease under high greenhouse gas concentrations, possibly associated with reductions in sea-ice cover. Our findings contradict the view that a warming world will automatically be one of more overall climatic variation. [ABSTRACT FROM AUTHOR]

Increases in temperature as a result of anthropogenically generated greenhouse gas (GHG) emissions are likely to impact key aspects of horticultural production. The potential effect of higher temperatures on fruit and nut trees' ability to break winter dormancy, which requires exposure to winter chilling temperatures, was considered. Three chill models (the 0-7.2°C, Modified Utah, and Dynamic models) were used to investigate changes in chill accumulation at 13 sites across Australia according to localised temperature change related to 1, 2 and 3°C increases in global average temperatures. This methodology avoids reliance on outcomes of future GHG emission pathways, which vary and are likely to change. Regional impacts and rates of decline in chilling differ among the chill models, with the 0-7.2°C model indicating the greatest reduction and the Dynamic model the slowest rate of decline. Elevated and high latitude eastern Australian sites were the least affected while the three more maritime, less elevated Western Australian locations were shown to bear the greatest impact from future warming. [ABSTRACT FROM AUTHOR]

best, the empirical evidence for human impact on climate change, more specifically, the anthropogenic global warming (AGW), is based on correlational research. That is, no experiment has been carried out that confirms or falsifies the causal hypothesis put forward by the International Panel on Climate Change (IPCC) that anthropogenic increasing of green house gas concentrations very likely causes increasing of the (mean) global temperature. In this article, we point out the major weaknesses of correlational research in assessing causal hypotheses. We further point out that the AGW hypothesis is in need of potential falsifiers in the Popperian (neopositivistic) sense. Some directions for future research on the formulation of such falsifiers in causal research are discussed. Of course, failure to find falsifying evidence in empirical climate data will render the AWG hypothesis much stronger. [ABSTRACT FROM AUTHOR]

Extremes of weather and climate can have devastating effects on human society and the environment. Understanding past changes in the characteristics of such events, including recent increases in the intensity of heavy precipitation events over a large part of the Northern Hemisphere land area, is critical for reliable projections of future changes. Given that atmospheric water-holding capacity is expected to increase roughly exponentially with temperature-and that atmospheric water content is increasing in accord with this theoretical expectation-it has been suggested that human-influenced global warming may be partly responsible for increases in heavy precipitation. Because of the limited availability of daily observations, however, most previous studies have examined only the potential detectability of changes in extreme precipitation through model-model comparisons. Here we show that human-induced increases in greenhouse gases have contributed to the observed intensification of heavy precipitation events found over approximately two-thirds of data-covered parts of Northern Hemisphere land areas. These results are based on a comparison of observed and multi-model simulated changes in extreme precipitation over the latter half of the twentieth century analysed with an optimal fingerprinting technique. Changes in extreme precipitation projected by models, and thus the impacts of future changes in extreme precipitation, may be underestimated because models seem to underestimate the observed increase in heavy precipitation with warming. [ABSTRACT FROM AUTHOR]

Marine and continental records show an abrupt negative shift in carbon isotope values at ?55.8?Myr ago. This carbon isotope excursion (CIE) is consistent with the release of a massive amount of isotopically light carbon into the atmosphere and was associated with a dramatic rise in global temperatures termed the Palaeocene-Eocene thermal maximum (PETM). Greenhouse gases released during the CIE, probably including methane, have often been considered the main cause of PETM warming. However, some evidence from the marine record suggests that warming directly preceded the CIE, raising the possibility that the CIE and PETM may have been linked to earlier warming with different origins. Yet pre-CIE warming is still uncertain. Disentangling the sequence of events before and during the CIE and PETM is important for understanding the causes of, and Earth system responses to, abrupt climate change. Here we show that continental warming of about 5?°C preceded the CIE in the Bighorn Basin, Wyoming. Our evidence, based on oxygen isotopes in mammal teeth (which reflect temperature-sensitive fractionation processes) and other proxies, reveals a marked temperature increase directly below the CIE, and again in the CIE. Pre-CIE warming is also supported by a negative amplification of ?13C values in soil carbonates below the CIE. Our results suggest that at least two sources of warming-the earlier of which is unlikely to have been methane-contributed to the PETM. [ABSTRACT FROM AUTHOR]

Global warming and accompanying climate change may be caused by an increase in atmospheric greenhouse gasses generated by anthropogenic activities. In order to supply such a mechanism of global warming with a quantitative underpinning, we need to understand the multifaceted roles of the Earth's energy balance and material cycles. In this study, we propose a new one-dimensional simple Earth system model. The model consists of carbon and energy balance submodels with a north–south zonal structure. The two submodels are coupled by interactive feedback processes such as CO2 fertilization of net primary production (NPP) and temperature dependencies of NPP, soil respiration, and ocean surface chemistry. The most important characteristics of the model are not only that the model requires a relatively short calculation time for carbon and energy simulation compared with a General Circulation Model (GCM) and an Earth system Model of Intermediate Complexity (EMIC), but also that the model can simulate average latitudinal variations. In order to analyze the response of the Earth system due to increasing greenhouse gasses, several simulations were conducted in one dimension from the years 1750 to 2000. Evaluating terrestrial and oceanic carbon uptake output of the model in the meridional direction through comparison with observations and satellite data, we analyzed the time variation patterns of air temperature in low- and middle-latitude belts. The model successfully reproduced the temporal variation in each latitude belt and the latitudinal distribution pattern of carbon uptake. Therefore, this model could more accurately demonstrate a difference in the latitudinal response of air temperature than existing models. As a result of the model evaluations, we concluded that this new one-dimensional simple Earth system model is a good tool for conducting global warming simulations. From future projections using various emission scenarios, we showed that the spatial distribution of terrestrial carbon uptake may vary greatly, not only among models used for climate change simulations, but also amongst emission scenarios. [ABSTRACT FROM AUTHOR]

Significant changes in physical and biological systems are occurring on all continents and in most oceans, with a concentration of available data in Europe and North America. Most of these changes are in the direction expected with warming temperature. Here we show that these changes in natural systems since at least 1970 are occurring in regions of observed temperature increases, and that these temperature increases at continental scales cannot be explained by natural climate variations alone. Given the conclusions from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report that most of the observed increase in global average temperatures since the mid-twentieth century is very likely to be due to the observed increase in anthropogenic greenhouse gas concentrations, and furthermore that it is likely that there has been significant anthropogenic warming over the past 50 years averaged over each continent except Antarctica, we conclude that anthropogenic climate change is having a significant impact on physical and biological systems globally and in some continents. [ABSTRACT FROM AUTHOR]

The author discusses aspects of the Kyoto Protocol and its impact on climate policy. He states that the Kyoto Protocol is the centrepiece of global efforts to address climate change by reducing greenhouse-gas emissions. He is critical that reasons for the Kyoto Protocol's ineffectiveness are in its architecture, which is based on carbon production, not carbon consumption.

Background: Climate change is safe to be one of the biggest challenges of mankind. Human activities, especially the combustion of fossil fuels, contribute to the increase of greenhouse gases in the atmosphere and thus to the pace of climate change. The effects of climate change are already being felt, and the resulting damage will most likely be enormous worldwide. Because global impacts vary widely and will lead to very different national vulnerability to climate impacts, each country, depending on its economic background, has different options to ward off negative impacts. Decisions have to be made to mitigate climate consequences according to the preparedness and the vulnerability of countries against the presumed impacts. This requires a profound scientific basis. To provide sound background information, a bibliometric study was conducted to present global research on climate change using established and specific parameters. Bibliometric standard parameters, established socioeconomic values, and climate change specific indices were used for the analyses. This allowed us to provide an overall picture of the global research pattern not only in terms of general aspects, but also in terms of climate change impacts, its effects and regional differences. For this purpose, we choose representative indices, such as the CO2 emissions for the responsibility of countries, the global climate risk index as a combination value for the different types of damage that countries can expect, the increase in sea level as a specific parameter as a measure of the huge global environmental impacts, and the readiness and vulnerability index for the different circumstances of individual countries under which climate change will take place. We hope to have thus made a comprehensive and representative selection of specific parameters that is sufficient to map the global research landscape. We have supplemented the methodology accordingly. Results: In terms of absolute publication numbers, the USA was the leading country, followed by the UK, and China in 3rd place. The steep rise in Chinese publication numbers over time came into view, while their citation numbers are relatively low. Scandinavian countries were leading regarding their publication numbers related to CO2 emission and socioeconomic indices. Only three developing countries stand out in all analyses: Costa Rica, the Fiji Atoll, and Zimbabwe, although it is here that the climate impact will be greatest. A positive correlation between countries' preparedness for the impacts of climate change and their publication numbers could be shown, while the correlation between countries' vulnerability and their publication numbers was negative. Conclusions: We could show that there exists an inequity between national research efforts according to the publication output and the demands and necessities of countries related to their socioeconomic status. This inequity calls for a rethink, a different approach, and a different policy to improve countries' preparedness and mitigation capacity, which requires the inclusion of the most affected regions of the world in a strengthened international cooperation network. [ABSTRACT FROM AUTHOR]

Climate change and global warming are the biggest challenges in the current century. Methane gas is one of the most important greenhouse gases which can contribute to creating warming weather (about 19%). In this research, satellite data from GOSAT and MODIS and also climatic data of precipitation, temperature and humidity are used to analyze monthly and seasonal methane changes in 2012 to 2018 in North America. The results show that the methane gas has increased during this period and it increases from 1789 to 1824 ppb. The gas has monthly fluctuation and in October and September has the maximum concentration and in March and April has the minimum value. The relationship between the methane gas and temperature and LST is positive, and the relationship between the methane gas and NDVI, precipitation and humidity is negative. This verifies that the increase in methane concentration has significant relationship with low vegetation cover and high temperature. Therefore, conservation of vegetation cover can help to reduce the methane concentration. [ABSTRACT FROM AUTHOR]

Global warming due to greenhouse gases and atmospheric aerosols alter precipitation rates, but the influence on extreme precipitation by aerosols relative to greenhouse gases is still not well known. Here we use the simulations from the Precipitation Driver and Response Model Intercomparison Project that enable us to compare changes in mean and extreme precipitation due to greenhouse gases with those due to black carbon and sulfate aerosols, using indicators for dry extremes as well as for moderate and very extreme precipitation. Generally, we find that the more extreme a precipitation event is, the more pronounced is its response relative to global mean surface temperature change, both for aerosol and greenhouse gas changes. Black carbon (BC) stands out with distinct behavior and large differences between individual models. Dry days become more frequent with BC-induced warming compared to greenhouse gases, but so does the intensity and frequency of extreme precipitation. An increase in sulfate aerosols cools the surface and thereby the atmosphere, and thus induces a reduction in precipitation with a stronger effect on extreme than on mean precipitation. A better understanding and representation of these processes in models will provide knowledge for developing strategies for both climate change and air pollution mitigation. Climate science: Aerosol and Black Carbon effect on precipitation Black carbon and sulfate aerosols have conflicting effects on global extreme dry and precipitation events. An international team of researchers led by Jana Sillmann at the Center for International Climate Research, Oslo use model simulations to examine the effect of sulfate aerosols and black carbon compared to greenhouse gases on global mean precipitation and extreme precipitation events. Sulfate aerosols, which cool the Earth's surface, decrease mean precipitation and in particular strongly reduce extreme precipitation events. Conversely, black carbon, which warms the Earth's surface, may increase the intensity and frequency of extreme precipitation events, but also reduces mean precipitation leading to more extreme dry drought-like conditions. This demonstrates the need to incorporate aerosols into future climate modeling effects on global precipitation trends. [ABSTRACT FROM AUTHOR]

Background: The climate change fact is intensive among the Middle East countries and especially Iran. Among the Middle East countries, Iran will experience an increase of 2.6 °C in mean temperatures and a 35% decline in precipitation in the next decades. In vice versa, Iran by total greenhouse gas (GHG) emissions nearly to 616,741 million tons of CO2 is the first responsible country to climate change in the Middle East, and seventh in the world. The high-level contribution of Iran to emissions of GHG depends on a significant production of oil, gas, and rapid urbanization. The present study aimed to reveal an overview of climate change facts and statistics in Iran.Results: In this manuscript, the evidential facts on climate change were investigated in global, regional, and national scales. For this purpose, the main increasing annual temperature and GHG emissions were considered. Besides, the variations of meteorological characteristics such as surface temperature, total precipitation, and upward longwave radiation (ULR) were reviewed in Iran indicating an anomalous decrease in precipitation events and anomalous increase in ULR and temperature characteristics confirming the global warming/climate change effects. Afterward, the legislative agreements on climate change concerning international adoptions and conventions were reviewed from Rio 1992 to NY 2016.Conclusions: The results showed that further research and development should be considered the novel methods to explore renewable energy applications and to mitigate GHG emissions in order to overcome the increased risk of climate change effects. Technological affairs and international participants should support this target. [ABSTRACT FROM AUTHOR]

The article discusses some of the most important aspects of the carbon cycle that have the potential to accelerate the rate of global warming beyond that attributed to human emissions of greenhouse gases. It discusses the impact of rising temperature and changing soil moisture on soil respiration. It also mentions the increase in disturbance in terrestrial ecosystems often linked with pulses of carbon to the atmosphere.

Changes in solar activity are regularly forwarded as an hypothesis to explain the observed global warming over the last century. The support of such claims is largely statistical, as knowledge of the physical relationships is limited. The statistical evidence is revisited. Changing solar activity is a statistically plausible hypothesis for the observed warming, if short-term natural variability is the only alternative explanation. Compared to the enhanced greenhouse effect, thesolar hypothesis looses a substantial part of its plausibility. Reversely, the size and significance of the estimated impact of the enhanced greenhouse effect on the global mean temperature is hardly affected by solar activity. [ABSTRACT FROM AUTHOR]