The Greta Thunberg Effect on Climate Equity: A Worldwide Google Trend Analysis

Abstract

Public opinion can strongly affect public policy when it focuses on issues of particular importance. In the midst of a current climate crisis, influencing public opinion can be one path to push the adoption of climate policy. Here, the impact of major media events on the public interest/concern for climate change was analyzed. Google Trends has emerged as a valid proxy for evaluating change in the space of public attention, but it only becomes usable after the back-transformation in absolute frequencies proposed here. In 2019, due to the “Greta Thunberg effect”, the duty-bearers, for the first time, showed greater concern than the rights-holder countries, breaking the paradigm that the more vulnerable countries are more worried about climate change. High public demand was created for strong climate policies and other future public actions that must be implemented to avert the current climate crisis.

1. Introduction

In 2019, Greta Thunberg, a 16-year-old Swedish native, brought extensive media attention to the idea of climate justice [1]. Greta Thunberg’s radical method of protest created the “Greta Thunberg effect”, which is inspiring a new generation to take a stance on climate justice as a political issue [2]. Greta Thunberg is not the first young climate activist, but few of her predecessors had the same kind of sustainable and disruptive effect. The “Greta Thunberg effect” has inspired teenagers to engage in climate activism and influenced groups of people who had not previously appeared interested in her agenda [3], generating one of the most widespread environmental social movements in history [4]. Young people have emerged as agents of change in a social movement of unprecedented scale aimed at stopping the global climate crisis [5]. They have adopted the language of justice to make climate change a salient issue and to reveal the failures and inactions of the existing establishment, including political leaders and fossil fuel companies [4].

Equity is the word that Greta Thunberg uses consistently in her speeches, from the speech to the European Parliament at Cop24 in Katowice (December 2018) that made her a household name to her speech at the UN climate action summit (September 2019) [6]. With regard to climate equity, the Office of the High Commissioner for Human Rights (OHCHR) calls for states to take action on climate change in accordance with their common but differentiated responsibilities and respective capabilities [7]. While climate change affects people everywhere, those who have contributed the least to greenhouse gas emissions are those most affected [8,9]. Therefore, high-emitting countries (duty-bearers) have an obligation to take effective measures to mitigate climate change and to ensure that low-emitting countries, which are more vulnerable (rights-holders), have the necessary capacity to adapt to the climate crisis. The mitigation of greenhouse gas (GHG) emissions and adaptation to climate risk are two essential ingredients of climate change policy [10]. We know from countries’ nationally determined contribution (NDC) statements that mitigation is a priority strategy for developed countries, while adaptation is a key climate change strategy for many developing countries [9]. In study [11], it was suggested that the main cause of the high vulnerability among low-emitting countries is a lack of adaptive capacity.

How can we convince duty-bearer countries to recognize the need to adopt policies based on principles of climate equity? This is likely one of the main environmental challenges of this historical period. There are many studies showing public opinion strongly affects public policy [12,13]. This mechanism works better when public policy is less manipulated by lobbies [14]. Given this background, it is clearly necessary to measure public opinion to follow its trend, particularly after important media events.

However, how can the evolution of public opinion at the global level be followed on a specific issue? One valuable option is offered by Google Trends. Google Trends has emerged as one of the best proxies for gauging public curiosity, attention, and issue salience [15]. Google search data have several major advantages over traditional survey data. First, the high cost of surveys means that they are carried out occasionally, making comparisons over time difficult. Second, there are many countries where surveys are not possible, whereas Google search data are available anywhere in the world with Internet connectivity. For these reasons, these data are increasingly utilized for applications in public health [16,17], economics and finance [18], tourism management [19], and nature conservation [15]. The main disadvantage of Google Trends is that it shows relative and not absolute search-term frequency [15]. Because of this, it has been noted that the temporal trends for search volume can vary depending on which terms are selected for analysis or even simply due to changes in the total number of searches over the time period under analysis [20,21]. Another important aspect is the validity of terms selected for analysis in relation to the topic of interest. It may be that the search volume recorded for such terms is driven by an association with factors other than those of interest. Therefore, some form of validation should be employed to ensure that the data are representative of the topic of study [22].

Given these premises, this paper aims to measure public opinion in order to identify historical media events that have shown the main potentialities to convince duty-bearer countries to recognize the need to adopt policies based on principles of climate equity.

2. Materials and Methods

With this in mind, first, the meanings of Google searches on the topics “climate change” and “global warming” with independent survey data (Section 3.1) were explored, and then the methodology proposed by Burivalova et al., 2018 was adapted in order to back-adjust Google Trends data to reflect the trend in the total volume of searches and to allow a geographic aggregation of data (Supplementary Materials). States were grouped, on the basis of climate equity criteria, as being closer to a duty-bearer or to a rights-holder country (Section 3.2). Since 2004, reciprocal changes in public interest in these topics were followed for these two groups, particularly as a result of the major events in climate change history in recent decades (Section 3.3).

2.1. Survey on Worldwide Climate Change Awareness

This study used open access data collected by the Pew Research Center for the Global Attitudes Survey dataset, with a primary focus on climate change. The Pew Research Center is a non-partisan “fact tank” located in Washington, DC, USA. The results for the survey were based on telephone and face-to-face interviews conducted under the direction of Princeton Survey Research Associates International. It was based on 45,435 face-to-face and telephone interviews in 40 countries with adults 18 and older, conducted from 25 March to 27 May 2015 [23]. The surveyed countries and data are presented in Supplementary Table S1. Two questions that were related to awareness about the risks of climate change were selected for comparison with the Google searches. For question Q32, participants were asked “In your view, is global climate change a very serious problem, somewhat serious, not too serious or not a problem?” Responses were classified as “Very serious”, “Somewhat serious”, “Not too serious”, and “Not a problem”. Only the category “Very serious” was considered. On average, 53 ± 17% of respondents considered climate change a very serious problem. Concerning question Q42, participants were asked “How concerned are you, if at all, that global climate change will harm you personally at some point in your lifetime?” Responses were classified as “Very concerned”, “Somewhat concerned”, “Not too concerned”, “Not at all concerned”, and “Climate change does not exist”. On average, 44 ± 21% of respondents declared that they were “Very concerned”. It is worth noting that awareness was not so high but had notable variability among countries.

2.2. Comparison between Google Searches and Survey Data

Google searches by country on the topics “climate change” (CC) and “global warming” (GW) were compared with the percentage of interviewers who considered CC/GW a “very serious problem” (Figure 1A) or who were “very concerned” (Figure 1B). The Google searches by country reported in Figure 1 referred to exactly 1 year before the end of the survey (27 May 2015). This temporal range maximized the correlation with the survey data for both the “climate change” and “global warming” topics. Different time frames (from 3 months to 3 years) showed analogues and significant correspondences. The degree of correlation among data was verified through Pearson’s correlation coefficient (r), and the normality of residuals was assessed using the Kolmogorov–Smirnov test [24]. This analysis was performed using the R software package “kolmim” with the function “ks.test”. The residuals were found to follow a normal distribution. Therefore, the parametric Pearson test was considered suitable for this set of data. This analysis was performed using the “cor.test” function and selecting “pearson” as the method [25].

2.3. Climate Vulnerability Scores

Country-level data on climate vulnerability were obtained from the Country Index of the Global Adaptation Initiative at the University of Notre Dame (ND-GAIN), a panel dataset of 192 countries for the 1995–2017 period [26,27]. Here, the most recent data were used (year 2017). The ND-GAIN Country Index is a metric used by scholars and policy makers to study climate vulnerability and adaptation opportunities in different countries and regions. The index was developed in consultation with a broad set of academics, practitioners, and private sector users [28], with a transparent methodology and a usable data format [29]. It defines vulnerability as a function of three components: exposure (the extent to which the human society is stressed by future changing climate conditions, i.e., physical factors external to the system), sensitivity (the degree to which people are affected by climate-related perturbations), and adaptive capacity (the ability of society to adjust to respond to the negative consequences of climate events). The ND-GAIN framework conceptualizes vulnerability with a composite metric constructed from thirty-six indicators across six sectors that reflect key aspects of human lives and livelihoods: (1) food, (2) water, (3) health, (4) ecosystem services, (5) human habitat, and (6) infrastructure. The ND-GAIN Country Index scores range from 0 to 1, with 1 representing the most vulnerable [26].

2.4. Carbon Dioxide Emissions

The EDGAR database is a joint project of the European Commission’s Joint Research Centre (JRC) and the PBL Netherlands Environmental Assessment Agency. Country-specific CO₂ emission totals include emissions from fossil fuel use and from the industry. The estimate does not consider CO₂ emissions from short-cycle biomass burning (such as agricultural waste burning), large-scale biomass burning (such as forest fires), and carbon emissions/removals of land use, land-use change, and forestry [30].

2.5. Geographical Grouping of Duty-Bearers and Rights-Holders

The M49 Standard coded by the Statistics Division of the United Nations was used for the classification of regions and subregions. The countries sharing climate inequity values that emerged from Figure 2 were aggregated according to the following geographic groupings: Africa (002); Latin America (Caribbean 29, Central America 013, South America 005); Northern America (021); Europe (150); Asia (Western Asia 145, Eastern Asia 030, Central Asia 143); Southern Asia (Southern Asia 034, South-eastern Asia 035, Oceanic islands 054, 057, 061); and Australia (Australia and New Zealand 053).

3. Results

3.1. What Do Google Searches on Climate Change Mean?

Data generated by search engines and social media have the potential to provide interesting insights into patterns and trends of public interest on environmental topics but only after a careful assessment and validation process [21,32,33]. Here, Google searches by country on the topics “climate change” (CC) and “global warming” (GW) were compared with the percentage of interviewers who considered CC/GW a “very serious problem” (Figure 1A) or who were “very concerned” (Figure 1B). The significant relationships found in Figure 1 highlighted that the public interest in CC/GW manifested through Google searches provided insights into worldwide awareness and concern about the CC/GW issue. Both the CC/GW topics showed significant correlations, although the Google searches on the CC topic seemed to be more representative. This was likely due to the more diffuse use of the CC than the GW term in recent years [34]. It was interesting that searches on the topic of CC seemed to represent people who are worried about the possible risks to their own safety (Figure 1B) more than a general awareness of the potential risk of CC (Figure 1A).

3.2. Climate Equity and Economic Equity: Duty-Bearers and Rights-Holders

The relationship of 174 countries between the per capita CO₂ emissions from fossil fuel use and CC vulnerability expressed with the ND-GAIN Country Index are explored in Figure 2. In line with the results of other studies, e.g., [8], it was evident that climate inequity was represented by the strong negative correlation (r = −0.85, p < 0.001) between being the architect or experiencing damage from CC. This climate inequity originates in the poor ability of more vulnerable countries to adapt to CC (Fussel, 2010), due to their low per capita gross domestic product (GDP) [35], while higher per capita CO₂ emissions are recorded for developed countries with a higher per capita GDP [36]. In summary, climate inequity is due to economic inequity.

On the basis of the correlation in Figure 2, countries were aggregated in the following geographical groupings: Northern America, Europe, Asia, Australia, Africa, Latin America, and Southern Asia The latter three groups are more vulnerable and contribute less to CC, and, to simplify the discussion of the results, they will be referred to herein as rights-holder countries, highlighting their greater need for adaptation. In contrast, the former four groups, which have a greater duty to take effective measures to mitigate CC, are named duty-bearer countries.

3.3. Geographic Grouping of Google Trends Data

Google Trends provides the relative frequency of search terms globally or by country. It adjusts the absolute number of searches in two ways. First, each month, it calculates the proportion of the searched term within the total Google searches. Next, it assigns the value 100 to the month (called the scale factor) during which the ratio is historically the highest; all remaining months are then scaled between 0 to 100. This post-processing does not allow Google Trends data to be geographically grouped because each country is made relative and scaled with respect to its own scale factor. Therefore, a procedure is required for geographical grouping (Supplementary Materials). Here, data by country were transformed in absolute frequencies according to [15], aggregated, made relative to the total Google search volume of each geographic group, and ultimately scaled (0–100) by choosing the scale factor among all compared groups. A notable aspect of this procedure for the regional grouping of data (Supplementary Materials) was the estimation of total Google search volume by country for the 2004–2019 period through proxies, such as Internet users and search engine market data, which are available at the country level, and a worldwide estimation of Internet traffic.

Validation at the global level of the proposed data processing is presented in Figure 3A, which shows the comparison between the CC trend provided directly by Google Trends (green) and a selection of the CC-transformed trends. As the scale factor used during the data conversion can be owned by more countries, the choice of which country to use to scale data (called a scale country) out of all other countries is arbitrary. (In this study, Fiji, Bolivia, and the Philippines were used.) Therefore, the impact of this choice is evaluated in Figure 3A (gray trends). The black line represents the mean of the three scale country trends tested here. Without any statistical analyses, it was visually clear that for global-level aggregation, the proposed data processing reproduced satisfactory data based on Google Trends, and the choice of the scale country had little influence at the global aggregation scale. Figure 3B shows the first application of this new procedure, which allowed us to know the CC trend of each geographic group we were interested in.

4. Discussion

4.1. The History of Public Interest in Climate Change

In Figure 3A, it can be noted that a substantial increase in CC search volume began on April 2007 following the release of the IPCC (Intergovernmental Panel on Climate Change) Fourth Assessment Report, coinciding with the rising popularity of the documentary “An Inconvenient Truth” by Al Gore, and this increase continued until the Norwegian Nobel Committee announced, on October 2007, the awarding of the Nobel Peace Prize equally to the IPCC and Al Gore [34]. A further and wider peak in public interest in CC was reached in 2009 after the high-profile media event related to the release of emails hacked from the Climate Research Unit at the University of East Anglia (colloquially known as ‘Climategate’) in November 2009 and the discovery of an error in the projections of the Himalayan glacier melt date in the IPCC Working Group II Fourth Assessment Report in January 2010 [37,38]. It was not until December 2015, with the negotiation of the Paris Agreement, and November 2016, when it came into effect, that global interest in CC began to rise again. Another important stage in the history of public interest in CC occurred in 2019, when Greta Thunberg initiated the first climate strike in March, the second in May, and the third in September 2019 (main peak), as an extraordinary number of people and organizations took part in these global climate strikes. An estimated 7.6 million people participated in 185 countries [39,40], and several grassroots organizations promoted the strike via their websites and social media channels [40,41].

4.2. What Is the “Greta Thunberg Effect” on Climate Equity?

In recent decades, Australia and Africa have shown to the rest of the world a greater public interest in the topic of CC (main graph of Figure 3B). Generally, all regions show two peaks, the first occurring in the 2007–2009 period, due to the Nobel Prize and Climategate, and the latter in 2019, related to the “Greta Thunberg Effect”. The inserts of Figure 3B point out that for rights-holder countries (first three graphs), the former peak was well pronounced, while the reaction to the “Greta Thunberg effect” was weak. In contrast, for the duty-bearer countries (last four graphs), except Asia, the second peak was more prominent, particularly in Northern America.

Figure 4 provides further analysis for investigating this discrepancy. In the left panels, regions were compared with rights-holder countries. Europe consistently showed a lower interest in CC than rights-holders, but the Nobel Prize and the “Greta Thunberg effect” (approximately +60% in 2019) shifted this in the countertrend (Figure 4A). North America was similar, except the readjustment started in concomitance with the Paris Agreement, and the “Greta Thunberg effect” was more impressive (approximately +130% in 2019) (Figure 4C). Australia (Figure 4E) consistently presented public interest on the topic of CC comparable to that of rights-holder countries, while Asia, on the contrary, always had a lower level of interest, which was not moved by the “Greta Thunberg effect”. (The weight of China in this finding was low because the use of Google as the search engine was low.) Adopting a changed perspective, in the right panels, regions were compared with rights-holder countries. The most interesting aspect was related to how strongly concern about CC risks could been seen in Africa, whereas duty-bearer countries showed similar concern only after the “Greta Thunberg effect” (Figure 4B).

In summary, in panel 4H, all duty-bearers were compared with all rights-holder countries. The former had always been less interested and likely less worried about CC risks. The same finding was presented by the study in [42], which used the 2007–2008 Gallup World Poll covering 119 countries and found that in developing countries, respondents generally perceived climate change as a much greater threat to themselves and their own family than did developed countries. However, the value of the data is confined to the years of the survey, as the global context for environmental issues is changing rapidly. In contrast, Google Trends data allowed us to see that this paradigm had changed, the Paris Agreement had balanced these differences, and the “Greta Thunberg effect” had turned the situation around.

The awarding of the Nobel Prize to Al Gore and the IPCC was a positive media event that decreased the difference between the two groups (Figure 5A). In contrast, Climategate, contributed significantly to increasing interest in CC globally (Figure 3A) and for both groups (Figure 4H), but it had a negative impact on the share of climate interest. The rights-holder countries reached an interest level double that of the duty-bearer countries, mainly in Africa and in Southern Asia. In the subsequent years, this surplus decreased until the Paris Agreement rebalanced the situation, but only with “the Greta Thunberg effect” in 2019, for the first time, did the duty-bearers show an interest, and thus a concern, greater than that of the rights-holders. Similar results were obtained when analyzing the GW topic (Supplementary Figure S5).

A further analysis (Figure 5B) showed the correlation between interest and vulnerability as related to CC. It was noted that the paradigm in which the more vulnerable countries were more interested and more worried about CC lost significance with the Greta Thunberg effect.

Generally, the “Greta Thunberg effect” is the increase in interest and concern regarding CC risks in the countries that can effectively implement suitable climate policy. However, what can this new awareness lead to? The study in [43] showed important evidence for how public opinion created demand for environmental policies in both the United States and Europe, which might then translate into current policy implementation.

A few months after the last global climate strike, the COVID-19 global pandemic crossed the globe, paralyzing any further new efforts, such as Thunberg’s, for building mass awareness and physical involvement in climate change [44]. In the meantime, what is happening with climate policy? Without arguing for a cause–effect relationship with the climate movement of 2019, we can simply observe the events of 2020 in the United States (US), the European Union (EU), and China. The new US President presented a 2020 election platform pledging to lead global efforts to ramp up climate targets and re-join the Paris Agreement [45]. The EU unveiled the Green New Deal, a commitment to be the first climate-neutral continent by 2050 [46], and China promised to become carbon neutral before 2060 and to begin cutting emissions within the next ten years [47]. Without sitting in judgement about the suitability of the climatic promises made in 2020, it is clear that it is critical to maintain high public interest in CC within duty-bearer countries to maintain elevated pressure on national and international climate policy.

5. Conclusions

This paper aimed to measure public opinion in order to identify historical media events, which have shown the main potentialities to convince duty-bearer countries to recognize the need to adopt policies based on principles of climate equity.

In this regard, the evolution of public opinion at the global level was followed on the issues “Climate Change, CC” and “Global Warming, GW” by Google Trends. Although Google Trends has emerged as one of the best proxies for gauging public curiosity, attention, and issue salience, the main disadvantage of Google Trends is that it shows relative and not absolute search-term frequency. Secondly, another important aspect is the validity of terms selected for analysis in relation to the topic of interest.

Concerning the latest aspect, in this study, the meaning of Google searches on the topics CC and GW with independent survey data was explored. The significant relationships found highlighted the fact that public interest in these topics manifested through Google searches provided insights into worldwide awareness and concern about these issues (Section 3.1). A wider validation of the search terms selected would be useful, and the unavailability of further surveys represented the mail limitation of this study.

Afterwards, the methodology proposed by Burivalova et al., 2018 was adapted in order to back-adjust Google Trends data to reflect the trend in the total volume of searches and to allow a geographic aggregation of data (Supplementary Materials). Future research on public opinions at the global level could benefit from the procedure developed in this study to aggregate Google search data at the regional level.

Since 2004, changes in public interest in these topics have been followed for duty-bearer and rights-holder countries, and the history of public interest in CC has been reconstructed (Section 4.1). A substantial increase in CC search volume began in 2007, following the release of the Fourth Assessment Report of IPCC and the Nobel Peace Prize equally awarded to the IPCC and Al Gore. A further and wider peak of public interest in CC was reached in 2009 after ‘Climategate’. It was not until 2015, with the negotiation of the Paris Agreement, that global interest in CC began to rise again. Another important stage in the history of public interest in CC occurred in 2019, when Greta Thunberg initiated the global climate strikes.

In conclusion, the analysis highlighted the particular importance of the “Greta Thunberg effect”: for the first time, the duty-bearers showed greater concern than the rights-holder countries, breaking the paradigm that more vulnerable countries are more worried about climate change. High public demand was created for strong climate policies and other future public actions that must be implemented to avert the current climate crisis.