Saturday, December 17, 2022

Short-term effective radiative forcing trends are difficult to verify, so caution is required in predictions/policy judgments that depend on them, such as the time remaining to, or the outstanding carbon budget consistent with, 1.5C warming

Is Anthropogenic Global Warming Accelerating? Stuart Jenkins et al. Journal of Climate, Vol 35, Issue 24, Pages 4273–4290, Nov 22 2022.

Abstract: Estimates of the anthropogenic effective radiative forcing (ERF) trend have increased by 50% since 2000 (from +0.4 W m−2 decade−1 in 2000–09 to +0.6 W m−2 decade−1 in 2010–19), the majority of which is driven by changes in the aerosol ERF trend, as a result of aerosol emissions reductions. Here we study the extent to which observations of the climate system agree with these ERF assumptions. We use a large ERF ensemble from the IPCC’s Sixth Assessment Report (AR6) to attribute the anthropogenic contributions to global mean surface temperature (GMST), top-of-atmosphere radiative flux, and we use aerosol optical depth observations. The GMST trend has increased from +0.18°C decade−1 in 2000–09 to +0.35°C decade−1 in 2010–19, coinciding with the anthropogenic warming trend rising from +0.19°C decade−1 in 2000–09 to +0.24°C decade−1 in 2010–19. This, as well as observed trends in top-of-atmosphere radiative fluxes and aerosol optical depths, supports the claim of an aerosol-induced temporary acceleration in the rate of warming. However, all three observation datasets additionally suggest that smaller aerosol ERF trend changes are compatible with observations since 2000, since radiative flux and GMST trends are significantly influenced by internal variability over this period. A zero-trend-change aerosol ERF scenario results in a much smaller anthropogenic warming acceleration since 2000 but is poorly represented in AR6’s ERF ensemble. Short-term ERF trends are difficult to verify using observations, so caution is required in predictions or policy judgments that depend on them, such as estimates of current anthropogenic warming trend, and the time remaining to, or the outstanding carbon budget consistent with, 1.5°C warming. Further systematic research focused on quantifying trends and early identification of acceleration or deceleration is required.

4. Consequences of alternative aerosol forcing trends

Successive IPCC reports have given assessments of the level of anthropogenic global warming, but no equivalent assessment of the rate of human-induced warming has been made. This is despite the rate of warming offering arguably more policy relevance at the present day in determining the time remaining to key goals of the Paris Agreement. This study highlights the key contributors to a perceived acceleration in the anthropogenic rate of warming since 2000 and uses observations of the climate system to constrain the forced response. Section 2 breaks down an ERF dataset that suggests anthropogenic ERF accelerated between 2000 and 2020, shown to arise because of aerosol forcing trends becoming positive around 2010 in the ERF ensemble. In section 3 we then step through three observational records to search for evidence supporting this assessed trend change.

Global temperatures show a clear change in trend between 2000 and 2020, characterized by temperatures remaining stable at around +1.0°C above preindustrial levels in the first decade, whereas in the second decade temperatures increase rapidly (with the rate of warming peaking at over +0.3°C decade−1). The reduced warming trend around 2000 has been discussed in the context of ocean heat uptake and natural variability (Masson-Delmotte et al. 2021; IPCC et al. 2013), but less research has focused on a possible warming acceleration in the following decade induced by aerosol ERF trend changes. By attributing the temperature trends to anthropogenic and natural ERFs we show that the forcing time series from Fig. 2 capture the broad warming contributions over the previous two decades (Fig. 4). However, significant variations around the anthropogenic best fit are still present (e.g., see the period of early Arctic warming in Fig. 4a), and alternative forcing trend change assumptions can be applied with little indication of a worse fit. A three-way regression isolates the aerosol contribution over history in Fig. 5, fitting the mid-twentieth-century GMST more successfully by downscaling the aerosol contribution. Hence, the aerosol ERF trend change contribution since 2000 is also downscaled, with best-estimate anthropogenic warming trend change around +0.05°C decade−1 between 2000–09 and 2010–19 (the 5th–95th-percentile range spans 0.01°–0.08°C decade−1). The aerosol contribution to this is +0.03°C decade−1 between 2000–09 and 2010–19 (the 5th–95th-percentile range spans 0.00°–0.07°C decade−1).

In the CERES record, LW TOA flux contributions are explained by recent GMST and forcing trends combined, while there is greater uncertainty in the contributors to the SW and net flux anomalies. In the SW anomaly, unforced variability in temperature and TOA flux time series precludes clear assessments of the aerosol ERF contribution, supporting the assessment that significant contributions from ENSO and PDO are present in recent TOA flux trend changes. Given this, TOA flux trends cannot rule out little to no anthropogenic ERF trend change over the two decades, despite the best-estimate anthropogenic ERF time series agreeing well with both TOA fluxes and temperature anomalies. Figure 6’s middle column (atmosphere-only TOA flux anomalies) and right column (coupled-model TOA flux anomalies) confirm the major role played by natural variability processes in these TOA flux records, demonstrating that the trend change induced in the SW TOA flux anomaly, where we expect to observe a large trend change induced by aerosols (Fig. 6h), is small relative to the trend change caused by unforced variability over the previous two decades (Fig. 6e). Continued funding for new satellites to study the outgoing radiative balance of the Earth system (such as the recently announced FORUM mission; ESA 2021) is vitally important in order to maintain long-term records and constrain radiative feedbacks with greater certainty.

Satellite observations and CMIP6 models agree that a relatively small AOD trend change has occurred over the last two decades, despite significant reductions in anthropogenic aerosol emissions in the Northern Hemisphere. Exploring a linear relationship between AOD and aerosol ERF trends (based on the mean response of CMIP6 models) allows us to estimate the ERF trend change expected in response to the observed AOD trend change since 2000. This analysis again supports the best estimate ERFs in Fig. 2, but also suggests that little-to-no trend change remains a possible assessment for ERF trends since 2000 in observations. The spatial pattern of aerosol emissions also may play a role in determining the aerosol ERF level (Stier et al. 2013), causing nonlinearities in the AOD and ERF responses to globally averaged aerosol emissions reductions. Further research of ERF trends and feedbacks using their full spatiotemporal signal in AMIP GCM experiments where forcing time series are known, and conducting regional aerosol perturbation experiments in coupled models (Wilcox et al. 2022), will provide more insight.

Overall, this assessment suggests that aerosol emissions reductions have contributed to an increase in the rate of anthropogenic warming since 2000, but both to a lesser degree than is suggested in the ERFs presented in Fig. 2, and with a substantial uncertainty range including the possibility of little contribution over two decades. The forced behavior coincides with a period of considerable internal variability, meaning that isolating the aerosol-induced ERF trend change from observations is challenging, and that a wide range of ERF scenarios offer plausible explanations of the past 20 years. Some of these possibilities are not well represented in the ERF ensemble shown in Fig. 2: for example, a zero-trend-change aerosol ERF scenario between 2000 and 2020 (shown in Fig. 2 as an dashed orange line, with the corresponding anthropogenic ERF a black dashed line), is considered possible in the analysis of all three observation datasets but is not represented well in the ERF ensemble of Fig. 2. Using a zero-trend-change aerosol ERF to attribute the anthropogenic contribution to global warming results in a similar quality fit to GMSTs (see dashed orange and black lines in Fig. 5, left panel), but substantially reduces the anthropogenic warming trend change that occurs since 2000 (orange and black dashed lines in Fig. 5, right panel). A comprehensive ERF ensemble of the recent time-history of anthropogenic ERF should offer these alternative scenarios, including scenarios with reduced aerosol ERF trend change since 2000 and with alternative rescalings for all pollutants using global energy balance constraints [e.g., those in Smith et al. (2021a) or Fig. 5].

The importance of continuing to track and constrain the early twenty-first century’s forcing trends is underappreciated, and future work should focus on providing better constraints to near-term forcing trends as well as their levels. Short-term ERF trends are vital to accurately assess this decade’s warming rate, with tangible, real-time impacts for global mitigation policy.

Think-tank employees favor military intervention much more than professors; those who favor interventionist policies are more likely to pursue positions to increase their policy influence

What Do Think Tanks Think? Proximity to Power and Foreign Policy Preferences. Richard Hanania, Max Abrahms. Foreign Policy Analysis, Volume 19, Issue 1, January 2023, orac031,

Abstract: Through the use of survey methods, the study presents the first systematic comparison of America-based international relations professors to think tank employees (TTEs) in terms of their preferred conduct of the United States in international affairs. The difference between the two groups in their support for military intervention is stark. TTEs are 0.47 standard deviations more hawkish than professors based on a standard measure of militant internationalism (MI). Controlling for self-described ideology mitigates this effect although it remains statistically significant. Beyond quantifying their relative foreign policy preferences, this study helps to resolve why TTEs tend to assume more hawkish policies. The authors find evidence that hawkishness is associated with proximity to power. Professors who have worked for the federal government score higher on MI, as do TTEs based at institutions located closer to Capitol Hill. In general, the results point to a self-selection mechanism whereby those who favor interventionist policies are more likely to pursue positions to increase their policy influence, perhaps because they know that powerful institutions are more likely to hire hawks. Alternative explanations for differences, such as levels or kinds of foreign policy expertise, have weaker empirical support.

Among older adults with subjective cognitive concerns, mindfulness training, exercise, or both did not result in significant differences in improvement in episodic memory or executive function at 6 months

Effects of Mindfulness Training and Exercise on Cognitive Function in Older Adults: A Randomized Clinical Trial. Eric J. Lenze et al. JAMA. 2022;328(22):2218-2229. doi:10.1001/jama.2022.21680

Key Points

Question  Does mindfulness training, exercise, or the combination of these interventions improve cognitive function in older adults with subjective cognitive concerns?

Findings  In this randomized clinical trial that included 585 participants, mindfulness training, exercise, or both did not result in significant differences in improvement in episodic memory or executive function composite scores at 6 months.

Meaning  The findings do not support the use of mindfulness training, exercise, or a combination of both for significantly improving cognitive function in older adults with subjective cognitive concerns.


Importance  Episodic memory and executive function are essential aspects of cognitive functioning that decline with aging. This decline may be ameliorable with lifestyle interventions.

Objective  To determine whether mindfulness-based stress reduction (MBSR), exercise, or a combination of both improve cognitive function in older adults.

Design, Setting, and Participants  This 2 × 2 factorial randomized clinical trial was conducted at 2 US sites (Washington University in St Louis and University of California, San Diego). A total of 585 older adults (aged 65-84 y) with subjective cognitive concerns, but not dementia, were randomized (enrollment from November 19, 2015, to January 23, 2019; final follow-up on March 16, 2020).

Interventions  Participants were randomized to undergo the following interventions: MBSR with a target of 60 minutes daily of meditation (n = 150); exercise with aerobic, strength, and functional components with a target of at least 300 minutes weekly (n = 138); combined MBSR and exercise (n = 144); or a health education control group (n = 153). Interventions lasted 18 months and consisted of group-based classes and home practice.

Main Outcomes and Measures  The 2 primary outcomes were composites of episodic memory and executive function (standardized to a mean [SD] of 0 [1]; higher composite scores indicate better cognitive performance) from neuropsychological testing; the primary end point was 6 months and the secondary end point was 18 months. There were 5 reported secondary outcomes: hippocampal volume and dorsolateral prefrontal cortex thickness and surface area from structural magnetic resonance imaging and functional cognitive capacity and self-reported cognitive concerns.

Results  Among 585 randomized participants (mean age, 71.5 years; 424 [72.5%] women), 568 (97.1%) completed 6 months in the trial and 475 (81.2%) completed 18 months. At 6 months, there was no significant effect of mindfulness training or exercise on episodic memory (MBSR vs no MBSR: 0.44 vs 0.48; mean difference, –0.04 points [95% CI, –0.15 to 0.07]; P = .50; exercise vs no exercise: 0.49 vs 0.42; difference, 0.07 [95% CI, –0.04 to 0.17]; P = .23) or executive function (MBSR vs no MBSR: 0.39 vs 0.31; mean difference, 0.08 points [95% CI, –0.02 to 0.19]; P = .12; exercise vs no exercise: 0.39 vs 0.32; difference, 0.07 [95% CI, –0.03 to 0.18]; P = .17) and there were no intervention effects at the secondary end point of 18 months. There was no significant interaction between mindfulness training and exercise (P = .93 for memory and P = .29 for executive function) at 6 months. Of the 5 prespecified secondary outcomes, none showed a significant improvement with either intervention compared with those not receiving the intervention.

Conclusions and Relevance  Among older adults with subjective cognitive concerns, mindfulness training, exercise, or both did not result in significant differences in improvement in episodic memory or executive function at 6 months. The findings do not support the use of these interventions for improving cognition in older adults with subjective cognitive concerns.

Parental Income and the Sexual Behavior of Their Adult Children: A Trivers–Willard Perspective

Parental Income and the Sexual Behavior of Their Adult Children: A Trivers–Willard Perspective. John T. Manning, Bernhard Fink, and Robert Trivers. Evolutionary Psychology, December 12, 2022.

Abstract: Parental income is negatively and linearly related to the digit ratio (2D:4D; a proxy for prenatal sex steroids) of their children. Children of parents with high income are thought to be exposed to higher prenatal testosterone and develop lower 2D:4D. It is further hypothesized that 2D:4D relates to sexual orientation, although it is unclear whether the association is linear or curvilinear. Here, we consider patterns of parental income and its association with the sexual behavior of their adult children in a large online study (the BBC internet study). There were curvilinear relationships with parental income in male and female children. The highest frequencies of homosexuality and bisexuality were found in the lowest income group (bottom 25% of the population), the lowest frequencies in the income group representing the upper 50% of the population, and intermediate values in the other groups (low 50% and top 25% of the population). Parental income showed a U-shaped association with scores for same-sex attraction and an inverted U-shaped association with opposite-sex attraction. Thus, for the first time, we show that same-sex attraction is related to parental income. The curvilinear relationship between parental income and sexual behavior in their adult children may result from an association between very high fetal estrogen or testosterone and attraction to partners of the same sex. Among non-heterosexuals, and in both sexes, very high fetal estrogen may be associated with femme or submissive sexual roles, and very high fetal testosterone with butch and assertive sexual roles.

Check also High-income women may prenatally masculinize their sons at the expense of the fitness of their daughters; low-income women may prenatally feminize their daughters at the fitness expense of their sons:

Parental income inequality and children’s digit ratio (2D:4D): a ‘Trivers-Willard’ effect on prenatal androgenization? J.T. Manning et al. Journal of Biosocial Science, February 2021.


The current study found that in male adult children, homosexuality was the most frequent non-heterosexual group and bisexuality was rare. For female adult children, bisexuality was more frequent than homosexuality. Parental income was related to the frequency of sexual orientation (heterosexuality, homosexuality, bisexuality) of their adult children. The association between parental income and sexual orientation of children was found in the total sample and when we considered the most numerous ethnic group (Whites) in the two largest national samples (UK and USA), thus confirming our prediction (i).
Parents with income that was “much lower than others” (bottom 25% of the population) had the highest frequencies of homosexuality and bisexuality for both male and female adult children. The lowest frequency of homosexuality was found in the male and female children of parents with an income “slightly higher than others” (upper 50% of the population). Parents with an income “much higher than others” (top 25% of the population) had male and female children with intermediate frequencies of homosexuality.
Concerning adult children's scores for sexual attraction to others, in men, same-sex attraction was highest among children of parents with an income corresponding to the bottom and top 25% of the population, and the lowest scores were found in children of parents with an income “slightly higher than others” (upper 50% of the population). For women, same-sex attraction was greatest for adult children of parents with an “income much lower than others” (bottom 25% of the population), lowest in children of parents with an income “slightly higher than others” (as for men) and intermediate for children of parents with an income representing the top 25% of the population. Splitting the sample for ethnicity (Whites only) and nation (UK and USA), UK scores for adult children's same-sex attraction were lower than those for the US with the former reporting the highest scores for the income group representing the bottom 25% of the population and the latter reporting very high scores for the highest income group (top 25% of the population). Overall, for both the frequency of sexual orientation groups and the same-sex attraction scores, we found no evidence for linear relationships. Concerning same-sex attraction scores, post hoc tests confirmed a U-shaped association such that the frequency of homosexuality/bisexuality and the magnitude of same-sex attraction scores were highest in the adult children from parents with the lowest (bottom 25% of the population) and to a lesser extent in parents with the highest income (top 25% of the population). The nadir of the attraction scores was observed in adult children from parents with an income “slightly higher than others” (upper 50% of the population). Therefore, our prediction (ii) was rejected and prediction (iii) was supported.
The curvilinear relationships between parental income and the sexual behavior of their adult children are, to our knowledge, novel. Our interpretation of these relationships is through the lens of the “Trivers–Willard” hypothesis (Trivers & Willard, 1973). We suggest that parental income is a marker of maternal condition (Babones, 2008Pickett & Wilkinson, 2015). Male children have a greater variance in reproductive success than female children in human and nonhuman animals (Bateman, 1948Trivers & Willard, 1973). Male children of mothers in poor condition (lowest parental income) will have below-average male reproductive success, but in contrast, daughters from mothers with the lowest parental income will have reproductive success closer to the female mean. Thus, mothers will be selected to favor their daughters depending on parental income by reducing their prenatal testosterone and increasing their prenatal estrogen. If mothers cannot distinguish between their male and female fetuses this will mean they expose their male offspring to a feminized fetal environment. Conversely, mothers in good condition (highest parental income) will androgenize their fetuses of both sexes. We have found high frequencies of homosexuality and bisexuality and same-sex attraction scores in adult children of mothers with the lowest and highest parental income. This suggests that both a high fetal estrogen-to-testosterone ratio and a high fetal testosterone-to-estrogen ratio are related to an increase in the probability of non-heterosexuality in adult children. We speculate that among the former, there may be a high proportion of “receptive” male homosexuals and “femme” female homosexuals. Among the latter, there may be a preponderance of “insertive” male homosexuals and “butch” female homosexuals.

In conclusion, the current study builds on the finding that parental income is negatively related to 2D:4D in both adult female and male children (Manning et al., 2022). Insofar as 2D:4D is a correlate of prenatal sex steroids and prenatal sex steroids influence sexual behavior, we predicted that parental income would be associated with children's sexual orientation and same-sex scores for sexual attraction to others. Our prediction was confirmed, so that compared to adult children of parents with the lowest income and those with an income “slightly higher,” the former was associated with higher frequencies of homosexuality and bisexuality and high attraction scores toward the same sex for both male and female adult children. Moreover, a comparison between children from “slightly higher” income families and those that had “much higher” income also showed an increase in homosexuality, bisexuality, and same-sex attraction scores in the latter. We suggest that very high fetal estrogen and testosterone are both associated with nonheterosexual behavior in adult male and female children. That is, prenatal sex steroids are related to sexual orientation in a U-shaped fashion. The relationship between 2D:4D and sexual orientation should now be reexamined for curvilinear effects. 

Increasing Tweeter access yields less corporate misconduct; effect is stronger for facilities of more visible firms; effect is concentrated in non-financial violations (unsafe workplace conditions or inappropriate treatment of employees/customers)

Heese, Jonas and Pacelli, Joseph, The Monitoring Role of Social Media (November 16, 2022). SSRN:

Abstract: In this study, we examine whether social media activity can reduce corporate misconduct. We use the staggered introduction of 3G mobile broadband access across the United States to identify exogenous increases in social media activity and test whether access to 3G reduces misconduct. We find that facilities reduce violations by 1.8% and penalties by 13% following the introduction of 3G in a local area. To validate social media activity as the underlying mechanism, we show that 3G access results in sharp increases in Tweet volume and that facilities located in areas with high Tweet volume engage in less misconduct. The effect of 3G access on misconduct is stronger for facilities of more visible firms and concentrated in non-financial violations, such as those involving unsafe workplace conditions and inappropriate treatment of employees and customers. Overall, our results demonstrate that social media plays an important role in monitoring corporate misconduct.

Keywords: corporate misconduct, social media, Twitter, mobile broadband.

JEL Classification: M40, M41, M43