Global Warming Hiatus Research Articles

Exploring Global Data Sets to Detect Changes in Soil Microbial Carbon and Nitrogen Over Three Decades

AbstractUnderstanding the temporal dynamics of soil microbial biomass is crucial for assessing soil ecosystem functions and services, yet these dynamics are globally uncertain. Here, we compiled a data set of soil microbial biomass carbon (MBC) and nitrogen (MBN) from 1493 studies between 1988 and 2019 to elucidate their temporal trends and potential drivers. Results showed that global MBC and MBN significantly decreased by 0.033 Mg C ha−1 yr−1 and 0.007 Mg N ha−1 yr−1 at 0–30 cm soil depth, between 1988 and 2019, respectively, which might be primarily attributed to the warming of the climate, the increase in global precipitation, and reduction of soil organic carbon (SOC) stock. The rate of decline in MBC and MBN showed a non‐linear trend: following a decline from 1988 to 1999, it slowed down until 2014, likely due to the global warming hiatus. Afterward, the pace of decline increased again from 2015 to 2019. Boreal biomes experienced the largest decrease in soil microbial biomass with the reduction rate of MBC being 4.3 times higher than in temperate biomes, showing a higher sensitivity in boreal biomes to climate change. Grassland ecosystems also exhibited greater reductions, possibly driven by their degradation. These findings shed valuable insights on the long‐term dynamics of soil microbial biomass on a global scale over the last three decades. Furthermore, this study underscores the importance of preserving soil microbial biomass as a key strategy to mitigate the adverse effects of future climate change, thereby sustaining ecosystem health and resilience.

Detecting climate milestones on the path to climate stabilization

The era of anthropogenic climate change can be described by defined climate milestones. These milestones mark changes in the historic trajectory of change, and include peak greenhouse gas emissions, peak greenhouse gas concentration, deceleration of warming, net-zero emissions, and a transition to global cooling. However, given internal variability in the Earth system and measurement uncertainty, definitively saying that a milestone has passed requires rigour. Here CMIP6 simulations of peak-and-decline scenarios are used to examine the time needed to robustly detect three climate milestones: (1) the slowdown of global warming; (2) the end of global surface temperature increase; and (3) peak concentration of CO2. It is estimated that it will take 40 to 60 years after a simulated slowdown in warming rate, to robustly detect ( >95% change) the signal in the global average temperature record. Detecting when warming has stopped will also be difficult and it takes until the mid 22nd century to have enough data to conclude warming has stopped. Detecting that CO2 concentration has peaked is far easier and a drop in CO2 concentration of 3 ppm is consistent with a greater than 99% chance that CO2 has peaked in all scenarios examined. Thus it is likely that as the rate of CO2 emissions is reduced, and net-zero emissions is approached, interpreting the global temperature record will become difficult—with a high potential to create confusion amongst policy makers and the general public.

Corals Evidence an Underestimation of the 20th Century Warming in the Eastern Pacific Cold Tongue

AbstractThe trade winds cause strong upwelling in the eastern equatorial Pacific, and create the eastern Pacific Cold Tongue (EPCT) that has far‐reaching impacts on global climate. However, large discrepancies persist in quantifying 20th‐century EPCT sea surface temperature (SST) changes across different instrumental data sets. Here we synthesize four coral Sr/Ca‐SST records from the tropical central‐eastern Pacific to develop a Cold Tongue Index (CTI) reconstruction for 1887–1997. The coral CTI record shows a rapid 20th century warming of the EPCT, suggesting an underestimation of warming trends in instrumental CTI records. The decadal to multidecadal changes in reconstructed EPCT SST show an association with the Walker Circulation. Our reconstruction indicates that recent EPCT cooling during the global warming hiatus is not unusual in the context of the 20th century. Our results provide new evidence for 20th century EPCT SST changes and an observational constraint for predicting future tropical climate changes.

Recent Cereal Phenological Variations under Mediterranean Conditions

This study analyzes the temporal patterns of rainfed cereal phenology extracted from the GIMMS NDVI3g dataset in the main cereal-growing regions under a Mediterranean climate in Spain, Portugal, France and Italy during the period 1982–2022. The series before and after the beginning of the 21st century were analyzed separately. Phenological parameters were extracted using the modified dynamic threshold method, and their trends were analyzed. Correlation analyses were performed to study the relationships among these parameters and to analyze the influence of hydroclimatic variables on the start (SOS) and end (EOS) of the growing season. Results showed a temporal reversal in phenological trends between both study periods, coinciding with the global warming hiatus. In the first period (1982–2002), SOS and EOS advanced (−7.5 and −3.1 days, respectively), and the length of growing season (LOS) increased. However, during the second stage (2003–2022), SOS and EOS were delayed (7.5 and 1.7 days, respectively), and LOS decreased. Similar dynamics were observed for the influence of the hydroclimatic variables on SOS and EOS, stronger in the first period and weaker in the second. This study provides valuable information on the phenological dynamics of rainfed cereals that may be useful for their management and planning in climate change scenarios.

Permafrost thermal dynamics at a local scale in northern Da Xing’anling Mountains

Permafrost in Northeastern China is not only controlled by latitude and elevation, but also locally environmental factors, such as vegetation cover and human activities. During 2009–2022, thinning active layer, increasing annual maximum frost depth in talik zones and lowering ground temperature above the depth of dividing point (DDP) between permafrost cooling and warming have been observed in many places, possibly due to the global warming hiatus (GWH). However, the responses of permafrost below DDP did not show a clear trend to the GWH, despite an evident ground warming. The warming and degradation of permafrost below DDP in the Da Xing’anling Mountains are more strongly influenced by the overall climate warming than by regional GWH. This study improves our understanding of changing permafrost temperature and its drivers. It also helps to provide data support and references for the management of the ecological and hydrological environment of the northern Da Xing’anling Mountains and the Heilongjiang-Amur River Basin.

Increasing marine heatwaves in the Gulf of Thailand after the global warming hiatus

Marine heatwaves (MHWs) have been reported often throughout the world, producing severe effects on marine ecosystems. However, the spatial pattern and trend of MHWs in the Gulf of Thailand (GOT) is still unknown. Based on high-resolution daily satellite data over a 40-year period from 1982 to 2021, changes in annual mean SST and MHW occurrences across the GOT are explored here. The results demonstrate that during a warming hiatus (1998–2009), annual mean SST in the GOT encountered a dropping trend, followed by an increasing trend during a warming reacceleration period (2010–2021). Although a warming hiatus and a warming reacceleration occurred in the annual mean SST after 1998, regional averaged SSTs were still 0.18 °C–0.42 °C higher than that for 1982–1997. Statistical distributions reveal that there was a significant shift in both annual mean SSTs and annual extreme hot SSTs. These changes have the potential to increase the frequency of MHWs. Further analysis reveals that MHW frequency has increased at a rate of 1.11 events per decade from 1982 to 2021, which is 2.5 times the global mean rate. For the period 2010–2021, the frequency and intensity of MHWs in the GOT have never dropped, but have instead been more frequent, longer lasting and extreme than those metrics of MHWs between 1982 and 2009. Furthermore, the findings highlight significant changes in the SST over the GOT that may lead us to change or modify the reference period of the MHW definition. The findings also suggest that heat transport and redistribution mechanisms in the GOT sea are changing. This study contributes to our understanding of MHW features in the GOT and the implications for marine ecosystems.

Global warming, a global energy resource

Global warming is a thermodynamic problem. When excess heat is added to the climate system, the land warms more quickly than the oceans due to the land’s reduced heat capacity. The oceans have a greater heat capacity because of their higher specific heat and the heat mixing in the upper layer of the ocean. Thermodynamic Geoengineering (TG) is a global cooling method that, when deployed at scale, would generate 1.6 times the world’s current supply of primary energy and remove carbon dioxide (CO2) from the atmosphere. The cooling would mirror the ostensible 2008–2013 global warming hiatus. At scale, 31,000 1-gigawatt (GW) ocean thermal energy conversion (OTEC) plants are estimated to be able to: a) displace about 0.8 watts per square meter (W/m2) of average global surface heat from the surface of the ocean to deep water that could be recycled in 226-year cycles, b) produce 31 terawatts (TW) (relative to 2019 global use of 19.2 TW); c) absorb about 4.3 Gt CO2 per year from the atmosphere by cooling the surface. The estimated cost of these plants is $2.1 trillion per year, or 30 years to ramp up to 31,000 plants, which are replaced as needed thereafter. For example, the cost of world oil consumption in 2019 was $2.3 trillion for 11.6 TW. The cost of the energy generated is estimated at $0.008/KWh.

Global warming, a global energy resource

Global warming is a thermodynamics problem. When excess heat is added to the climate system, the land warms more quickly than the oceans due to the land’s reduced heat capacity. The oceans have a greater heat capacity because of its higher specific heat and the heat mixing in the upper layer of the ocean. Thermodynamic Geoengineering (TG) is a global cooling method which deployed at scale would generate 1.6 times the world’s current supply of primary energy and remove carbon dioxide (CO2) from the atmosphere. The cooling would mirror the ostensible 2008–2013 global warming hiatus. At scale 31,000 1-gigawatt (GW) ocean thermal energy conversion (OTEC) plants are estimated to be able to: a) displace about 0.8 watts per square meter (W/m2) of average global surface heat from the surface of the ocean to deep water that could be recycled in 226-year cycles, b) produce 31 terawatts (TW) (relative to 2019 global use of 19.2 TW and c) absorb about 4.3 Gt CO2 per year from the atmosphere by cooling the surface. The estimated cost of these plants is $2.1 trillion per year or 30 years to ramp up to 31,000 plants which are replaced as needed thereafter. Compared for example to the cost of world oil consumption that in 2019 was $2.3 trillion for 11.6 TW. The cost of the energy generated is estimated at $0.008/KWh.

Fossil Fuel, Greenhouse Gas and Global Warming

Since the Industrial Revolution, fossil fuel consumption and greenhouse gas emission have increased substantially, causing the rise of greenhouse gas concentration (GHGC) and in turn the rise of global mean surface temperature (GMST). We analyze the years of the rises and the falls of global temperature fluctuation, and find that the natural time interval between the rise and the fall of the temperature fluctuation has decreased from 31.5 years to 23 years, the impact from human activities has increased from 2.5 years to 9 years. We analyze the shares of total solar irradiance (TSI), greenhouse gas concentration (GHGC), and water vapor for the rise ofGMST, we find that: TSI accounts for 23.4% for greenhouse effect from 1880 to 1964, and 12.4% from 1965 to 2022; GHGC accounts for 80.9% for greenhouse effect from 1880 to 1964,and 86.6% from 1965 to 2022; water vapor is negatively related with GMST from 1880 to 1964, accounting for -4.3% for greenhouse effect, and positively related with GMST from 1965 to 2022, accounting for 1% for greenhouse effect. Global warming hiatus from 1998 to 2012 is a shortened fall of global temperature fluctuation.

Non-symmetric responses of leaf onset date to natural warming and cooling in northern ecosystems.

The northern hemisphere has experienced regional cooling, especially during the global warming hiatus (1998-2012) due to ocean energy redistribution. However, the lack of studies about the natural cooling effects hampers our understanding of vegetation responses to climate change. Using 15,125 ground phenological time series at 3,620 sites since the 1950s and 31-year satellite greenness observations (1982-2012) covering the warming hiatus period, we show a stronger response of leaf onset date (LOD) to natural cooling than to warming, i.e. the delay of LOD caused by 1°C cooling is larger than the advance of LOD with 1°C warming. This might be because cooling leads to larger chilling accumulation and heating requirements for leaf onset, but this non-symmetric LOD response is partially offset by warming-related drying. Moreover, spring greening magnitude, in terms of satellite-based greenness and productivity, is more sensitive to LOD changes in the warming area than in the cooling. These results highlight the importance of considering non-symmetric responses of spring greening to warming and cooling when predicting vegetation-climate feedbacks.

Unexpected cooling Eurasia during February of global-warming slowdown: Roles of North Atlantic and Arctic Oceans

The latest global mean surface temperature (GMST) indices from several datasets all show a significant warming trend during the so-called period of global-warming slowdown (i.e., 1998–2012), albeit at a more modest rise compared with the satellite era in the 20th century. Via the Mann-Kendall trend test, this study further examined the trend of GMST from a monthly perspective. It is surprising to find that a significant negative trend occurs only in February and the robust cooling is most evident in the mid–high latitudes of Eurasia. Then an empirical orthogonal function (EOF) based on multi-sources data (MS-EOF) was applied on the February surface air temperature (SAT) over Eurasia. Focus is given on the characteristics and factors of the leading MS-EOF mode (MS-EOF1), as in the trend pattern, which features a uniform cooling mode dominating the mid–high latitudes of Eurasian continent. The key circulation features a large-scale eastward-shift North Atlantic Oscillation (NAO)-like pattern, which is, in a negative phase, favourable for weakening the polar-front jet stream and transporting cold air from the Arctic regions to the mid-high latitudes of Eurasian continent. Relevant precursor signals can be traced back to the anomalous North Atlantic sea surface temperature (SST) and Barents–Kara sea ice in the preceding autumn, together contributing significantly to the cooling February over middle- to high-latitude Eurasia and is verified by a linear baroclinic model. This finding emphasizes the important contribution of cooling February to the famous global-warming slowdown.

Ambiguous Variations in Tropical Latent Heat Flux since the Years around 1998

Abstract The tropical latent heat flux (LHF) has experienced a significant increase under the background of global warming in the past four decades. However, since the years around 1998, the long-term LHF variations in the tropics have been found to be quite different in various flux products. Three different trends in the LHF, climbing, near zero, and declining, are suggested by five widely used flux products, which hinders our knowledge of the actual LHF variations. Although there are buoy observations in the tropics, these observations are hard to use to evaluate flux products as they have been assimilated and/or used as benchmarks in the flux data production. This study aims to identify credible long-term LHF variations since 1998. A linear model decomposing the LHF variations into contributions from sea surface wind U and air–sea humidity differences is first applied. The linear model results show that the LHF variations have been more positively connected to U variations since 1998. Evidence from in situ and remote sensing observations is subsequently employed to identify how U has varied recently. Both Global Tropical Moored Buoy Array (GTMBA) buoy observations (from 82 buoys) and a multisensor merged satellite product support a slightly downward trend in U in the last two decades. Such a weakening of U is not conducive to oceanic evaporation and leads to a reduced LHF. Consequently, a declining LHF under a weakening U since the emergence of the global warming “hiatus” in approximately 1998 might be more convincing in the sense of data accuracy and physical consistency. Significance Statement The latent heat flux acts as the language of air–sea interactions. This study aims to examine how the tropical latent heat flux has changed since the emergence of the global warming slowdown in approximately 1998. The most striking finding is that the long-term variations in the tropical latent heat flux are fairly inconsistent in several widely used flux products in the last two decades. The sea surface wind variation is found to be the primary contributor to the latent heat flux variation after 1998. Observational evidence from buoy and remote sensing data is hence employed to clarify the actual sea surface wind and the latent heat flux variations.

Separating Anthropogenically‐ and Naturally‐Caused Temperature Trends: A Systematic Approach Based On Climate Memory Analysis

AbstractSeparating anthropogenic and natural contributions to global warming is crucial for understanding and predicting climate change, but it is challenging due to the complexity of the climate system. In this study, we try to address this issue by estimating the anthropogenic forcing impacts with its long‐term persistence features properly considered. In this way, a data‐driven approach is proposed to decompose the observed trends from global and regional scales into anthropogenically‐ and naturally‐caused trends. We find that there is a continuous anthropogenic global warming trend since the beginning of the last century, even during the recent global warming hiatus period. On regional scales, the anthropogenically‐forced trends among regions are found at a similar level, while their unevenly distributed warming trends among regions may be attributed to natural causes. Our findings provide new insight into climate warming, and our approach based on persistence analysis provides a new perspective for attribution studies.

Spatiotemporal Patterns of Land Surface Phenology from 2001 to 2021 in the Agricultural Pastoral Ecotone of Northern China

Vegetation phenology is one of the most sensitive indicators to understanding terrestrial ecosystem status and change. However, few studies have been conducted to reveal vegetation phenology variation characteristics over the past two decades, especially under the background of the global warming hiatus since 1998. The agricultural pastoral ecotone of northern China (APENC) is an ideal place to analyze land surface phenology (LSP) variation. Therefore, the spatiotemporal patterns of LSP were quantitatively analyzed at regional, basin and pixel scales based on time-series MODIS NDVI data (2001–2021). Results showed that: (i) The start of the growing season (SOS) occurred in 105–141 Julian days, the end of the growing season (EOS) was between 257 and 281 Julian days and the length of the growing season (LOS) varied from 130 to 172 days. The later SOS was mainly distributed in croplands and typical grassland areas, while the early SOS was observed in forests and sandy vegetation coverage areas. The early EOS occurred in typical grasslands, and the later EOS was concentrated in the southeast boundary. The magnitude of the SOS and LOS fluctuation was less than EOS. (ii) The SOS and EOS exhibited overall insignificant advanced and delayed trends at a rate of −0.09 days·yr−1 and 0.12 days·yr−1, respectively, and the LOS displayed an insignificant extended trend at a rate of 0.26 days·yr−1 at a regional scale. The trends of phenological metrics were consistent with the APENC in the Yellow River and Haihe River Basins. The shortened trend of LOS occurred due to the delayed SOS and advanced EOS in the Songliao River and Continental Basins. (iii) The SOS variation gradually changed from an advanced trend to a delayed trend from a southwest to northeast direction in cropland and grassland ecosystems, whereas an opposite trend was found for EOS. The LOS exhibited a significant extended trend due to the significant advanced and delayed trend of SOS and EOS at p < 0.01 in forest ecosystems. This work provides a critical reference for the vegetation phenology dynamic research of semi-arid and semi-humid regions.

Satellite observed reversal in trends of spring phenology in the middle-high latitudes of the Northern Hemisphere during the global warming hiatus.

The start of the growing season (SOS) is essential to track the responses of vegetation to climate change. However, recent findings on whether the SOS in the middle-high latitudes of the Northern Hemisphere (NH) continued to advance or reversed during the global warming hiatus were not consistent. It is necessary to investigate the causes of this controversy and to examine the relationship between the SOS and preseason temperature trends. To this end, we first applied four widely used phenology extraction methods to derive the SOS from the GIMMS NDVI3g dataset and then used the ensemble empirical modal decomposition (EEMD) method to extract the nonlinear trends of the SOS and preseason temperature. Our results clarify, for the first time, that the limitations of the linear assumption-based trend analysis methods are an important but overlooked cause of the discrepancies among existing studies on whether the SOS was advanced or delayed in the NH (>30° N) during the global warming hiatus. We further revealed the range of the mismatches between the SOS and preseason temperature trends at the latitude, altitude and biome levels. Specifically, we discovered that the SOS in the NH (>30° N) obtained by the four phenology extraction methods showed a significant reversal from advance to delay during the global warming hiatus, and the corresponding average rate of change was very small. The area showing increasing preseason temperatures decreased during the global warming hiatus, but it always occupied most of the NH (>30° N). However, delayed SOS trends were dominant in the NH from 50° N to 60° N, above 3000 m and in biomes other than TBMF and BF. Accordingly, using an EEMD-like approach to evaluate the changes in the SOS and preseason temperature is necessary for improving our understanding of the changes in the SOS and their association with climate.

Application of facilitated transfer mechanisms of SEBS/[P(14)666][TMPP] composite membrane on CH4/N2 separation

CH4/N2 separation is one of the most challenging gas separation tasks and plays a significant role in the global warming hiatus. Membrane-based separation is a promising method for industrial applications but has been limited by its poor CH4/N2 selectivity. Therefore, an ionic liquid with excellent differential binding properties to CH4 and N2 is required for this study. [P(14)666][TMPP] (bis (2,4,4 trimethylpentyl) phosphinate, trihexyl (tetradecyl) phosphanium) was selected from 26 ionic liquids (ILs) to prepare IL-polymer membranes (ILPMs). It led to a 57.9 % increase in CH4/N2 selectivity of 7.31 and a 2539.9 % increase in CH4 permeability of 128.3 barrer compared with neat membrane. DFT simulations reveal that the facilitated transfer mechanism could enhance CH4/N2 separation. This study also shows that (1) the C-H···O forms hydrogen bonding (HB); (2) the differences of CH4 and N2 in geometry and electrostatic potential (ESP) distribution lead to different steric hindrance effects that could be the decisive factor for the outstanding performance of prepared ILPMs in this study.

Continued spring phenological advance under global warming hiatus over the Pan-Third Pole.

The global surface temperature has witnessed a warming hiatus in the first decade of this century, but how this slowing down of warming will impact spring phenology over Pan-Third Pole remains unclear. Here, we combined multiple satellite-derived vegetation indices with eddy covariance datasets to evaluate the spatiotemporal changes in spring phenological changes over the Pan-Third Pole. We found that the spring phenology over Pan-Third Pole continues to advance at the rate of 4.8 days decade-1 during the warming hiatus period, which is contrasted to a non-significant change over the northern hemisphere. Such a significant and continued advance in spring phenology was mainly attributed to an increase in preseason minimum temperature and water availability. Moreover, there is an overall increasing importance of precipitation on changes in spring phenology during the last four decades. We further demonstrated that this increasingly negative correlation was also found across more than two-thirds of the dryland region, tentatively suggesting that spring phenological changes might shift from temperature to precipitation-controlled over the Pan-Third Pole in a warmer world.

Detection of surface water temperature variations of Mongolian lakes benefiting from the spatially and temporally gap-filled MODIS data

• We applied an effective spatiotemporal gap-filled method to improve the LSWT from MODIS. • The long-term variations of the annual and seasonal mean LSWTs of Mongolian lakes were provided. • The LSWT of Mongolian lakes confirmed the phenomenon “global warming hiatus”. Lakes provide critical water resources for human activities and ecosystems, particularly in the Mongolian Plateau (MP), which is characterized by a dry climate and a harsh environment. As a region that is sensitive to anthropogenic warming, tracking lake surface water temperature (LSWT) changes in Mongolian lakes is crucial for understanding the consequences of a warming climate on lake ecosystems. However, the long-term monitoring of LSWT is restricted by the spatiotemporal gaps in the raw imagery of remote sensing-based land surface temperature (LST), e.g., the commonly used Moderate Resolution Imaging Spectroradiometer (MODIS) LST products. This study applied an improved gap-filling method by utilizing the discrete cosine transform-based penalized least squares (DCT-PLS) strategy in the spatial domain combined with the linear interpolation (LI) algorithm in the temporal domain. The method was applied to fill gaps in the LSWT imagery of 12 representative lakes across MP. The randomly sampled high-quality MODIS LSWT values in the spatial and temporal domains were excavated as false data gaps and considered “virtual true” validation datasets. The spatial validation results showed that the estimated LSWT for all the lake cases were comparable with the “virtual true” LSWT values, with the average values of the coefficient of determination, mean absolute error, mean square error, and root mean square error being 0.98, 0.38 °C, 0.45 °C, and 0.59 °C, respectively. Meanwhile, the error of nighttime LSWT results was relatively lower than that of daytime LSWT. For temporal interpolation validation, the LI algorithm exhibited relatively better performance and could more objectively indicate the variation in LSWT. Benefiting from the spatially and temporally well-constrained data, we analyzed the interannual and intra-annual change characteristics of the LSWTs of the 12 lakes. The long-term variations of annual and seasonal mean LSWTs in the 12 selected lakes exhibited no evident trends in 2000–2020, while presented apparent interannual fluctuations. The slight changes in the average LSWTs of the 12 selected lakes were in excellent synchronization with the surrounding LST derived from the reanalysis datasets, confirming the widely reported phenomenon of “global warming hiatus” that occurred in the early 21st century. This study improves the understanding of the LSWT variations in Mongolian lakes in response to global climate change. It has the potential to provide an effective approach for monitoring LSWT changes in other large-scale studies.

Comprehensive Analysis of Ocean Current and Sea Surface Temperature Trend under Global Warming Hiatus of Kuroshio Extent Delineated Using a Combination of Spatial Domain Filters

The effect of climate prevails on a diverse time scale from days to seasons and decades. Between 1993 and 2013, global warming appeared to have paused even though there was an increase in atmospheric greenhouse gases. The variations in oceanographic variables, like current speed and sea surface temperature (SST), under the influence of the global warming hiatus (1993–2013), have drawn the attention of the global research community. However, the magnitude of ocean current and SST characteristics oscillates and varies with their geographic locations. Consequently, investigating the spatio-temporal changing aspects of oceanographic parameters in the backdrop of climate change is essential, specifically in coastal regions along Kuroshio current (KC), where fisheries are predominant. This study analyzes the trend of ocean current and SST induced mainly during the global warming hiatus, before and till the recent time based on the daily ocean current data from 1993 to 2020 and SST between 1982 and 2020. The Kuroshio extent is delineated from its surrounding water masses using an aggregation of raster classification, stretching, equalization, and spatial filters such as edge detection, convolution, and Laplacian. Finally, on the extracted Kuroshio extent, analyses such as time series decomposition (additive) and statistical trend computation methods (Yue and Wang trend test and Theil–Sen’s slope estimator) were applied to dissect and investigate the situations. An interesting downward trend is observed in the KC between the East coast of Taiwan and Tokara Strait (Tau = −0.05, S = −2430, Sen’s slope = −5.19 × 10−5, and Z = −2.61), whereas an upward trend from Tokara Strait to Nagoya (Tau = 0.89, S = 4344, Sen’s slope = 8.4 × 10−5, and Z = 2.56). In contrast, a consistent increasing SST in trend is visualized in the southern and mid-KC sections but with varying magnitude.

Major Contribution of Halogenated Greenhouse Gases to Global Surface Temperature Change

This paper aims to better understand why there was a global warming pause in 2000–2015 and why the global mean surface temperature (GMST) has risen again in recent years. We present and statistically analyze substantial time-series observed datasets of global lower-stratospheric temperature (GLST), troposphere–stratosphere temperature climatology, global land surface air temperature, GMST, sea ice extent (SIE) and snow cover extent (SCE), combined with modeled calculations of GLSTs and GMSTs. The observed and analyzed results show that GLST/SCE has stabilized since the mid-1990s with no significant change over the past two and a half decades. Upper-stratospheric warming at high latitudes has been observed and GMST or global land surface air temperature has reached a plateau since the mid-2000s with the removal of natural effects. In marked contrast, continued drastic warmings at the coasts of polar regions (particularly Russia and Alaska) are observed and well explained by the sea-ice-loss warming amplification mechanism. The calculated GMSTs by the parameter-free quantum-physics warming model of halogenated greenhouse gases (GHGs) show excellent agreement with the observed GMSTs after the natural El Niño southern oscillation and volcanic effects are removed. These results have provided strong evidence for the dominant warming mechanism of anthropogenic halogenated GHGs. The results also call for closer scrutiny of the assumptions made in current climate models.