Reply to Li &amp; Yang's comments on “Comparing the current and early 20th century warm periods in China”

Soon, Willie; Connolly, Ronan; Connolly, Michael; O’Neill, Peter; Zheng, Jie; Ge, Quansheng; Hao, Zhixin; Yan, Hong

doi:10.1016/j.earscirev.2019.102950

Cited by 4 publications

(17 citation statements)

References 15 publications

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“…We showed that there is considerable debate over how warm the earlier warm period is relative to the current warm period. Indeed, this debate is ongoing, e.g., see Li and Yang (2019) and our reply (Soon et al, 2019). However, hopefully this should illustrate how you need to be very careful in making these sort of generic statements, when you are referring to the IPCC!…”

Section: C4mentioning

confidence: 84%

“…In this context, we provided a review of Chinese temperature trends in Soon et al (2018). You might also find the ensuing discussion, i.e., Li and Yang (2019) and Soon et al (2019) relevant.…”

Section: ) Resultsmentioning

confidence: 99%

“…The snow cover trends for China have received some discussion and debate in the literature lately because they appear to be different from much of the Northern Hemisphere, e.g., see Wei and Dong, 2015;Wang et al, 2017;Chen et al, 2016. 3. Recently, some of us (and others) have been encouraging more research into the differences in climatic trends in different regions within China, e.g., Soon et al, 2018;Li and Yang, 2019;Soon et al, 2019. Therefore, this study is also useful because the authors provide the breakdown for the trends of each of the three main snow cover regions in China as well as the national trends.…”

Section: Chinamentioning

confidence: 96%

“…Indeed, as I will discuss below, if anything, their results are problematic for the IPCC's claims on snow cover. For this reason, the authors should either drop the discussion of anthropogenic global warming or else provide a more critical evaluation of how their results compare/contrast with the IPCC report (and other literature, e.g., Connolly et al, 2019). C3…”

Section: Chinamentioning

confidence: 99%

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Referee Comment - tc-2019-152

Connolly¹

2019

Preprint

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General comments The authors have used the Chinese Meteorological Administration (CMA)'s daily snow depth dataset for China that covers the period, 1951-2013, to study and describe the annual variations in snow cover across China over the period, 1952-2012 (because they define the hydrological year as July-June, they were unable to include 1951 or 2013). This dataset is constructed from ground-based meteorological measurements taken from hundreds of meteorological stations distributed across most of China. The authors derive several different metrics of snow cover from this dataset and compare and contrast the annual trends for each of these metrics. They also describe separately the trends for the three main snow cover areas in China (northeast China; northern Xinjiang; and the Tibetan Plateau) as well as the overall trends for all C1 TCD

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Section: C4mentioning

confidence: 84%

Section: ) Resultsmentioning

confidence: 99%

Section: Chinamentioning

confidence: 96%

Section: Chinamentioning

confidence: 99%

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Referee Comment - tc-2019-152

Connolly¹

2019

Preprint

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“…We will show that the standard estimates used by IPCC (2013) [2], which include urban as well as rural stations, imply a much greater long-term warming than most other estimates. This suggests that the standard estimates have not adequately corrected for urbanization bias [56,[116][117][118].…”

Section: Introductionmentioning

confidence: 99%

How much has the Sun influenced Northern Hemisphere temperature trends? An ongoing debate

Connolly¹,

Soon²,

Connolly³

et al. 2021

Res. Astron. Astrophys.

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In order to evaluate how much Total Solar Irradiance (TSI) has influenced Northern Hemisphere surface air temperature trends, it is important to have reliable estimates of both quantities. Sixteen different estimates of the changes in TSI since at least the 19th century were compiled from the literature. Half of these estimates are “low variability” and half are “high variability”. Meanwhile, five largely-independent methods for estimating Northern Hemisphere temperature trends were evaluated using: 1) only rural weather stations; 2) all available stations whether urban or rural (the standard approach); 3) only sea surface temperatures; 4) tree-ring widths as temperature proxies; 5) glacier length records as temperature proxies. The standard estimates which use urban as well as rural stations were somewhat anomalous as they implied a much greater warming in recent decades than the other estimates, suggesting that urbanization bias might still be a problem in current global temperature datasets – despite the conclusions of some earlier studies. Nonetheless, all five estimates confirm that it is currently warmer than the late 19th century, i.e., there has been some “global warming” since the 19th century. For each of the five estimates of Northern Hemisphere temperatures, the contribution from direct solar forcing for all sixteen estimates of TSI was evaluated using simple linear least-squares fitting. The role of human activity on recent warming was then calculated by fitting the residuals to the UN IPCC’s recommended “anthropogenic forcings” time series. For all five Northern Hemisphere temperature series, different TSI estimates suggest everything from no role for the Sun in recent decades (implying that recent global warming is mostly human-caused) to most of the recent global warming being due to changes in solar activity (that is, that recent global warming is mostly natural). It appears that previous studies (including the most recent IPCC reports) which had prematurely concluded the former, had done so because they failed to adequately consider all the relevant estimates of TSI and/or to satisfactorily address the uncertainties still associated with Northern Hemisphere temperature trend estimates. Therefore, several recommendations on how the scientific community can more satisfactorily resolve these issues are provided.

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Evaluation of the Homogenization Adjustments Applied to European Temperature Records in the Global Historical Climatology Network Dataset

O’Neill

Connolly²,

Connolly³

et al. 2022

Atmosphere

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The widely used Global Historical Climatology Network (GHCN) monthly temperature dataset is available in two formats—non-homogenized and homogenized. Since 2011, this homogenized dataset has been updated almost daily by applying the “Pairwise Homogenization Algorithm” (PHA) to the non-homogenized datasets. Previous studies found that the PHA can perform well at correcting synthetic time series when certain artificial biases are introduced. However, its performance with real world data has been less well studied. Therefore, the homogenized GHCN datasets (Version 3 and 4) were downloaded almost daily over a 10-year period (2011-2021) yielding 3689 different updates to the datasets. The different breakpoints identified were analyzed for a set of stations from 24 European countries for which station history metadata were available. A remarkable inconsistency in the identified breakpoints (and hence adjustments applied) was revealed. Of the adjustments applied for GHCN Version 4, 64% (61% for Version 3) were identified on less than 25% of runs, while only 16% of the adjustments (21% for Version 3) were identified consistently for more than 75% of the runs. The consistency of PHA adjustments improved when the breakpoints corresponded to documented station history metadata events. However, only 19% of the breakpoints (18% for Version 3) were associated with a documented event within 1 year, and 67% (69% for Version 3) were not associated with any documented event. Therefore, while the PHA remains a useful tool in the community’s homogenization toolbox, many of the PHA adjustments applied to the homogenized GHCN dataset may have been spurious. Using station metadata to assess the reliability of PHA adjustments might potentially help to identify some of these spurious adjustments.

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Reply to Li & Yang's comments on “Comparing the current and early 20th century warm periods in China”

Cited by 4 publications

References 15 publications

Referee Comment - tc-2019-152

Referee Comment - tc-2019-152

How much has the Sun influenced Northern Hemisphere temperature trends? An ongoing debate

Evaluation of the Homogenization Adjustments Applied to European Temperature Records in the Global Historical Climatology Network Dataset

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