On the role of natural multidecadal oscillations on global warming and its hiatus

2021 ◽  
Author(s):  
Mayukha Pal ◽  
Prasanta K Panigrahi
Keyword(s):  
Global Warming ◽  
Wavelet Transforms ◽  
Temperature Reconstruction ◽  
Global Temperature ◽  
Temperature Records ◽  
Warming Hiatus ◽  
Biased Judgments ◽  
Instrumental Temperature ◽  
Multiple Tree

Abstract In this study, we investigate the role of the multidecadal oscillation patterns in the global temperature in the global warming hiatus. We analyze the global instrumental temperature records and multiple tree-ring temperature reconstruction records using wavelet transforms and register the presence of a multidecadal cycle of approximately 55-75 years. The hiatus and post-hiatus rise in temperature arises from the declining phase of the multidecadal oscillation which temporally compensates the rising phase. The unusual rise in the temperature after the hiatus is possibly explained by the positive uprising phase of this natural cycle. The origin of the global warming debate has been partly ascribed to faulty calculations or biased judgments. However, in these studies, little emphasis has been given to the possible presence of multidecadal oscillation patterns in the global temperature, which may lead to such an effect. Our result demonstrates that, phase of this cycle has accidentally played an important role in fueling the global warming debate. Therefore, while assessing any future climate changes, such possibilities should be accounted.

scholarly journals Pacific variability reconciles observed and modelled global mean temperature increase since 1950

2020 ◽  
Author(s):  
Martin B. Stolpe ◽  
Kevin Cowtan ◽  
Iselin Medhaug ◽  
Reto Knutti
Keyword(s):  
Global Warming ◽  
Temperature Change ◽  
Temperature Increase ◽  
Global Temperature ◽  
Global Mean Temperature ◽  
Mean Temperature ◽  
The Pacific ◽  
Global Warming Hiatus ◽  
Warming Hiatus ◽  
Global Mean

Abstract Global mean temperature change simulated by climate models deviates from the observed temperature increase during decadal-scale periods in the past. In particular, warming during the ‘global warming hiatus’ in the early twenty-first century appears overestimated in CMIP5 and CMIP6 multi-model means. We examine the role of equatorial Pacific variability in these divergences since 1950 by comparing 18 studies that quantify the Pacific contribution to the ‘hiatus’ and earlier periods and by investigating the reasons for differing results. During the ‘global warming hiatus’ from 1992 to 2012, the estimated contributions differ by a factor of five, with multiple linear regression approaches generally indicating a smaller contribution of Pacific variability to global temperature than climate model experiments where the simulated tropical Pacific sea surface temperature (SST) or wind stress anomalies are nudged towards observations. These so-called pacemaker experiments suggest that the ‘hiatus’ is fully explained and possibly over-explained by Pacific variability. Most of the spread across the studies can be attributed to two factors: neglecting the forced signal in tropical Pacific SST, which is often the case in multiple regression studies but not in pacemaker experiments, underestimates the Pacific contribution to global temperature change by a factor of two during the ‘hiatus’; the sensitivity with which the global temperature responds to Pacific variability varies by a factor of two between models on a decadal time scale, questioning the robustness of single model pacemaker experiments. Once we have accounted for these factors, the CMIP5 mean warming adjusted for Pacific variability reproduces the observed annual global mean temperature closely, with a correlation coefficient of 0.985 from 1950 to 2018. The CMIP6 ensemble performs less favourably but improves if the models with the highest transient climate response are omitted from the ensemble mean.

Role of Indian Ocean SST variability on the recent global warming hiatus

2016 ◽  
Vol 143 ◽  
pp. 21-30 ◽  
Author(s):  
Anika Arora ◽  
Suryachandra A. Rao ◽  
R. Chattopadhyay ◽  
Tanmoy Goswami ◽  
Gibies George ◽  
...  
Keyword(s):  
Global Warming ◽  
Indian Ocean ◽  
Sst Variability ◽  
Global Warming Hiatus ◽  
Warming Hiatus

Global warming might be on hold, but it’s not cancelled

2016 ◽  
Author(s):  
Iselin Medhaug
Keyword(s):  
Global Warming ◽  
Greenhouse Gases ◽  
Climate Models ◽  
Oil And Gas ◽  
Global Climate ◽  
Global Climate Models ◽  
Global Temperature ◽  
Steady Increase ◽  
Cast Doubt ◽  
Warming Hiatus

Instrumental measurements of surface temperatures are available back to around 1850. Based on these, we can estimate the annual mean global temperature. Global temperatures are clearly rising, mainly because of increasing amounts of greenhouse gases, like for example CO2 and methane, from use of coal, oil and gas and deforestation. Since 1998, a paradox seems to have appeared, where the global temperature has stopped rising even with a steady increase in release of greenhouse gases into the atmosphere. This period has popularly been called the “global warming hiatus” or “paused warming”, and it has been used to cast doubt on whether man made global warming is really happening, or that it can be called off. By using 17 different global climate models, and also available temperature observations, we have tried to figure out why the temperature increase might stop, what is actually happening, whether it has happened before or it may happen again in a warmer world, and which regions have higher chances of experiencing “hiatus” periods lasting for a decade or so.

scholarly journals Detection of non‐climatic biases in land surface temperature records by comparing climatic data and their model simulations

2021 ◽  
Author(s):  
Nicola Scafetta
Keyword(s):  
Global Warming ◽  
North America ◽  
South America ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Global Temperature ◽  
Sea Surface ◽  
Temperature Record ◽  
The World ◽  
Temperature Records

AbstractThe 0.6 °C warming observed in global temperature datasets from 1940 to 1960 to 2000–2020 can be partially due to urban heat island (UHI) and other non-climatic biases in the underlying data, although several previous studies have argued to the contrary. Here we identify land regions where such biases could be present by locally evaluating their diurnal temperature range (DTR = TMax − TMin trends between the decades 1945–1954 and 2005–2014 and between the decades 1951–1960 and 1991–2000 versus their synthetic hindcasts produced by the CMIP5 models. Vast regions of Asia (in particular Russia and China) and North America, a significant part of Europe, part of Oceania, and relatively small parts of South America (in particular Colombia and Venezuela) and Africa show DTR reductions up to 0.5–1.5 °C larger than the hindcasted ones, mostly where fast urbanization has occurred, such as in central-east China. Besides, it is found: (1) from May to October, TMax globally warmed 40% less than the hindcast; (2) in Greenland, which appears nearly free of any non-climatic contamination, TMean warmed about 50% less than the hindcast; (3) the world macro-regions with, on average, the lowest DTR reductions and with low urbanization (60S-30N:120 W–90 E and 60 S–10 N:90 E–180 E: Central and South America, Africa, and Oceania) warmed about 20–30% less than the models’ hindcast. Yet, the world macro-region with, on average, the largest DTR reductions and with high urbanization (30 N–80 N:180 W–180 E: most of North America, Europe, and Central Asia) warmed just a little bit more (5%) than the hindcast, which indicates that the models well agree only with potentially problematic temperature records. Indeed, also tree-based proxy temperature reconstructions covering the 30°N–70°N land area produce significantly less warming than the correspondent instrumentally-based temperature record since 1980. Finally, we compare land and sea surface temperature data versus their CMIP5 simulations and find that 25–45% of the 1 °C land warming from 1940–1960 to 2000–2020 could be due to non-climatic biases. By merging the sea surface temperature record (assumed to be correct) and an adjusted land temperature record based on the model prediction, the global warming during the same period is found to be 15–25% lower than reported. The corrected warming is compatible with that shown by the satellite UAH MSU v6.0 low troposphere global temperature record since 1979. Implications for climate model evaluation and future global warming estimates are briefly addressed.

The recent global warming hiatus: What is the role of Pacific variability?

2015 ◽  
Vol 42 (3) ◽  
pp. 880-888 ◽  
Author(s):  
H. Douville ◽  
A. Voldoire ◽  
O. Geoffroy
Keyword(s):  
Global Warming ◽  
Global Warming Hiatus ◽  
Warming Hiatus

scholarly journals A Link between the Hiatus in Global Warming and North American Drought

2015 ◽  
Vol 28 (9) ◽  
pp. 3834-3845 ◽  
Author(s):  
Thomas L. Delworth ◽  
Fanrong Zeng ◽  
Anthony Rosati ◽  
Gabriel A. Vecchi ◽  
Andrew T. Wittenberg
Keyword(s):  
Global Warming ◽  
North America ◽  
Surface Temperature ◽  
North American ◽  
Radiative Forcing ◽  
Tropical Pacific ◽  
Global Warming Hiatus ◽  
Warming Hiatus ◽  
The Impact ◽  
The Tropical Pacific

Abstract Portions of western North America have experienced prolonged drought over the last decade. This drought has occurred at the same time as the global warming hiatus—a decadal period with little increase in global mean surface temperature. Climate models and observational analyses are used to clarify the dual role of recent tropical Pacific changes in driving both the global warming hiatus and North American drought. When observed tropical Pacific wind stress anomalies are inserted into coupled models, the simulations produce persistent negative sea surface temperature anomalies in the eastern tropical Pacific, a hiatus in global warming, and drought over North America driven by SST-induced atmospheric circulation anomalies. In the simulations herein the tropical wind anomalies account for 92% of the simulated North American drought during the recent decade, with 8% from anthropogenic radiative forcing changes. This suggests that anthropogenic radiative forcing is not the dominant driver of the current drought, unless the wind changes themselves are driven by anthropogenic radiative forcing. The anomalous tropical winds could also originate from coupled interactions in the tropical Pacific or from forcing outside the tropical Pacific. The model experiments suggest that if the tropical winds were to return to climatological conditions, then the recent tendency toward North American drought would diminish. Alternatively, if the anomalous tropical winds were to persist, then the impact on North American drought would continue; however, the impact of the enhanced Pacific easterlies on global temperature diminishes after a decade or two due to a surface reemergence of warmer water that was initially subducted into the ocean interior.

Extreme North America Winter Storm Season of 2013/14: Roles of Radiative Forcing and the Global Warming Hiatus

2015 ◽  
Vol 96 (12) ◽  
pp. S25-S28 ◽  
Author(s):  
Xiaosong Yang ◽  
G. A. Vecchi ◽  
T. L. Delworth ◽  
K. Paffendorf ◽  
L. Jia ◽  
...  
Keyword(s):  
Global Warming ◽  
North America ◽  
Radiative Forcing ◽  
Winter Storm ◽  
Global Warming Hiatus ◽  
Warming Hiatus ◽  
Extreme North
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