Pre-service chemistry teachers’ understanding of knowledge related to climate change

Abstract

Climate change presents a global human challenge, and many countries are paying increased attention to climate change issues. Chemistry plays a critical role in addressing climate change. The dual nature of pre-service chemistry teachers’ identity determines the importance of their understanding of climate change. This study employed a phenomenography methodological framework and semi-structured interviews to explore 16 pre-service chemistry teachers’ understanding of climate change's manifestations, causes, impacts, and ways to cope with climate change. The results showed that although pre-service chemistry teachers had a certain knowledge of climate change, their understanding of the concepts of climate change, global climate warming, and greenhouse effects and their interrelatedness was ambiguous or false. Their explanations of the harm caused by acid rain, the mechanism of ozone layer destruction, and the greenhouse effect were inadequate. Factors that influenced pre-service chemistry teachers’ understanding of climate change included school curriculum, particularly chemistry courses, science popularisation aided by information technology, and their informal education through social life experiences. These findings provide insights into pre-service chemistry teachers’ professional development and higher education's approach to teaching about climate change.

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Introduction

Today's world is experiencing increasing climate anomalies, acid precipitation, ozone layer depletion, sea level rise, glacier melting, and other adverse phenomena. As such trends intensify, climate change increasingly affects communities worldwide (IPCC, 2014; IPCC, 2021; USGCRP, 2017), and it has become an important global research topic. Many researchers have conducted in-depth studies on climate change effects and related issues. For example, research has shown that climate change is associated with deteriorating human health (Rhea et al., 2021), the incidence of Parkinson's is positively related to acid precipitation (Schwartz and Williamson, 2021), climate change can lead to unfavourable plant growth (Zandalinas et al., 2021), global warming increases the risk of flooding (Kam et al., 2021), and any one of the other climate factors may produce a domino effect as global warming increases (Wunderling et al., 2021). Considering climate change's negative impact on the earth, researchers are continually exploring the anomalies’ mechanisms and suggesting ways to mitigate them, such as identifying factors that accelerate global warming (Richardson, 2022), analysing ways to mitigate global warming through systems thinking and sustainable development (Mella, 2022), analysing ozone layer depletion causes and potential recovery methods (Akhobadze, 2020), and proposing recovery and complementary resilience plans in response to climate change (Woodruff et al., 2022).

China first mentioned the concept of a ‘community of common destiny’ in its 2011 white paper China's Peaceful Development, stating that ‘humanity has only one home on Earth’ (China SCIO, 2011). Recently, China has been paying greater attention to climate change issues, and the government has released annual reports on climate change, such as Responding to Climate Change: China's Policies and Actions (2020), which clearly states that ‘climate change is a common challenge facing mankind’. The government has incorporated carbon peaking and carbon neutrality into the overall layout of ecological civilisation and launched the National Climate Change Adaptation Strategy 2035 (China SCIO, 2021).

Climate change has gained attention in international scientific research and has become a social science subject of interest to many scholars. Climate change is not only a social phenomenon and research topic but is also a significant school curriculum topic. The theme of ‘climate change’ permeates many university subjects, and relates closely in particular to chemical science. Acid precipitation, the ozone layer, and greenhouse gases are significant topics in chemistry. Students’ in-depth comprehension of matter's particle nature and reactions within specific elemental compounds will help them to better understand climate change. As a central science urgently needed by society, chemistry plays an irreplaceable role in addressing climate change-related issues.

The dual identity of pre-service chemistry teachers determines the importance of their understanding of climate change. As college students, pre-service chemistry teachers will become future citizens of society and assume the future of national development (Littrell et al., 2022), just as they will become chemistry teachers who influence chemistry education in the future. Considering these dual attributes of pre-service chemistry teachers’ identities, this study employed a phenomenography methodological framework, semi-structured interviews, and constructivist grounded theory to explore the following core questions:

(1) What is pre-service chemistry teachers’ understanding of the climate change and related topics?

(2) What factors influence pre-service chemistry teachers’ knowledge and understanding of the climate change topic?

We explored these issues by investigating Chinese pre-service chemistry teachers’ knowledge of climate change topics at different grade levels. The results provide suggestions for and insights into teaching about climate change, especially in higher education institutions, to contribute to pre-service chemistry teachers’ professional development.

Literature review

Climate change has become a concerning issue worldwide. Students are future citizens who will affect environmental development and social progress. Therefore, more researchers are focusing on students’ knowledge of climate change and their understanding of the climate change concept, its causes and possible impacts, and how to address and solve it. This research focus has produced a series of meaningful findings and insights.

(1) Students often misunderstand the concept of climate change, but teaching courses related to climate change promotes better understanding. College students often confuse climate change with other environmental issues (Huxster et al., 2015). They may understand other environmental issues’ different characteristics, such as climate change and the greenhouse effect, but they do not understand all the issues and the relationships between them. Therefore, they confuse some of the concepts underlying climate change, such as the greenhouse effect, global warming, and the ozone layer (Dawson and Palmer, 2015; Versprille and Towns, 2015). College students also lack a particle-level understanding of greenhouse gases and have difficulty understanding the greenhouse effect's mechanism and its correspondence with increased CO₂ concentration and climate change impacts (Versprille and Towns, 2015). Research shows that college major, gender, and grade level influence students’ understanding of climate change, which has implications for teaching and curriculum development that will improve students’ understanding of climate change (Zhao and Ewert, 2021). For example, students can improve their understanding of climate change by taking related courses (Klapp and Bouvier-Brown, 2021), such as ecological society courses, which help students to better understand climate change (Prasad and Mkumbachi, 2021). Further, students can participate in climate change-related teaching units as this also increases their understanding of climate change (Bofferding and Kloser, 2015). Moreover, process-oriented inquiry learning is an effective teaching tool that improves students’ understanding and attitudes towards the concept of climate change (Cascolan and Prudente, 2018). Researchers proposed a framework for teaching the climate system based on students’ conceptual and scientific perspectives (Shepardson et al., 2012), and explored how students conceptualise a climate system (Shepardson et al., 2014). Research has further shown that students’ understanding of climate change significantly increases when teachers provide even brief instruction during the teaching process (Lombardi and Sinatra, 2012).

(2) Students’ understanding of climate change sources is incomplete. There is a consensus that climate change is almost certainly caused by humans (Arto-Blanco et al., 2017), and most students acknowledge humans’ responsibility for climate change. However, students mostly believe that climate change is related to the hole in the ozone layer. For example, a 2016 study found that 50% of students mentioned ozone depletion as an important factor in triggering climate change (Stevenson et al., 2016). Additionally, students’ understanding of the causes of climate change is strongly related to their age; young people's understanding of the causes of the greenhouse effect has been found to increase with each grade (Frappart et al., 2018).

(3) Students appreciate the impact of climate change and its serious dangers. They are aware of the impact of climate change on the environment and that climate change exacerbates climate events, such as droughts, storm surges, and hurricanes (O’Hare, 2013). For example, climate change leads to global warming, increasing glacier melting and rising sea levels, posing threats to island countries (Prasad and Mkumbachi, 2021). Students are aware of the climate change effects on humans, such as the increased risk of skin cancer, heart disease, and other illnesses (Andersson and Wallin, 2000). Moreover, they believe that global warming only affects temperature, and has little effect on precipitation (Shepardson et al., 2011). Additionally, students have little understanding of climate change's economic impacts, such as the effects on migration (Punter et al., 2011).

(4) Students have an important role in addressing and solving climate change. With a thorough understanding of climate change, students can contribute positively to community development by developing mitigation and adaptation methods (Mugambiwa and Dzomonda, 2018). Therefore, climate change should be included in the higher education curriculum (Arto-Blanco et al., 2017). Previous studies indicate that the most accepted climate change mitigation options involve planting trees (Kilinc et al., 2009), reducing pollution (Garg and Lal, 2022), especially factory pollution (Daniel et al., 2004), and reducing traffic (Bofferding and Kloser, 2015). However, students’ understanding of this problem is incomplete and only scratches the surface.

Previous research focuses on primary and middle school students; few studies investigate university students’—especially pre-service chemistry teachers’—understanding of climate change. A few university education studies explored the importance of climate change knowledge and suggestions for university teaching from the perspective of earth sciences, but very few studies have explored the understanding of global climate change among university students majoring in teacher education from the perspective of the chemical sciences. Therefore, this study explored Chinese pre-service chemistry teachers’ understanding of climate change knowledge. The findings provide suggestions for and insights into teaching and curriculum development in both basic and higher education.

Method

Research tools

Phenomenography is an educational research method that was developed by a research team in the Department of Education, University of Gothenburg, Sweden, in the late 1960s and early 1970s. The method describes and classifies ideas that are generated when people experience specific phenomena, and then integrates an understanding of qualitative differences obtained through description into a systematic and structured idea system. Phenomenography defines people's understanding and conceptualisation of a phenomenon and it attempts to identify multiple concepts or meanings that a specific group has for that phenomenon. This method is typically used to explore changes in students’ conceptions of a scientific topic (Bodner and Orgill, 2007).

Phenomenography research employs interviews that conform to its theoretical framework as a data collection method. It is a basic psychological research method used to understand individuals’ psychology and behaviour through their relative communication with researchers. In this study, we conducted semi-structured interviews to identify pre-service chemistry teachers’ understanding of climate change issues at different grade levels.

We developed the study's semi-structured interview outline after reviewing the existing literature and consulting two university chemistry experts. The interview comprised five dimensions that addressed conceptual issues and chemical knowledge related to climate change: (1) an overall understanding of climate change; (2) climate change manifestations, including an understanding of global warming, acid precipitation, ozone layer depletion, and other related issues; (3) reasons for climate change, including an understanding of issues related to the greenhouse effect; (4) climate change's impact; and (5) ways to deal with climate change. See Appendix 1 for a detailed interview outline.

Participants

Pre-service teachers are future teacher candidates enrolled in grades one to four at normal colleges or comprehensive universities, majoring in education, with a clear career goal of future employment in education and teaching in schools or educational institutions at all levels. Study participants were randomly selected from pre-service chemistry teachers in their freshman and senior years of chemistry teacher education at a key province-run comprehensive university in Shandong Province, China. We selected freshmen for this study because first-year students have just entered the university and not yet experienced systematic college chemistry learning; therefore, they represent the most primitive level of pre-service teachers. We selected seniors because these students have finished the first three years of university-level organic chemistry, inorganic chemistry, analytical chemistry, physical chemistry, and professional chemical courses, such as curriculum and chemistry teaching pedagogy; therefore, they represent pre-service teachers at a higher level. The status quo of pre-service chemistry teachers’ knowledge of climate change in these two school stages could reflect the influence of college education on pre-service teachers’ understanding of climate change.

Sample sizes are usually small in most phenomenography studies due to the concentrated nature of the analysis topics; a sample of 15–20 participants is usually considered large enough to reveal possible ideas and plausible explanations (Trigwell, 2000). From the student sample (those who volunteered to participate in the research), we randomly selected eight pre-service chemistry teachers at the freshman stage and eight pre-service chemistry teachers at the senior stage; these are numbered PCT-F-01 to 08 (4 males, 4 females) and PCT-S-01 to 08 (4 males, 4 females). The 16 participants’ characteristics are shown in Table 1.

Table 1 Participant characteristics (N = 16)

Participant	Year	Gender	Age
PCT-F-01	Freshman	Female	19
PCT-F-02	Freshman	Male	19
PCT-F-03	Freshman	Female	19
PCT-F-04	Freshman	Female	18
PCT-F-05	Freshman	Male	18
PCT-F-06	Freshman	Male	20
PCT-F-07	Freshman	Male	18
PCT-F-08	Freshman	Female	19
PCT-S-01	Senior	Female	22
PCT-S-02	Senior	Male	22
PCT-S-03	Senior	Female	22
PCT-S-04	Senior	Male	23
PCT-S-05	Senior	Male	22
PCT-S-06	Senior	Female	22
PCT-S-07	Senior	Male	23
PCT-S-08	Senior	Female	23

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Data collection

Prior to the study, we obtained permission from the participants’ college to recruit them for the study. We informed the participants of the study's purpose, content, and process, and that they could leave the study at any time. All participants provided written informed consent to participate, which conveyed that they would be videotaped and recorded in full. We used numerical codes in place of participants’ names to ensure privacy and confidentiality and protected their data to the fullest extent possible.

Before beginning the formal interviews, the researchers ensured they had an in-depth understanding of all the information related to the interview questions, and that they were fully familiar with the interview content and process. The interviews were conducted over two weeks.

Researchers interviewed each participant separately according to the interview outline. The researchers maintained sufficient self-reflection and flexibility, listened and recorded well, captured timely responses that were valuable to the study, and skilfully followed up, affirming participants’ ideas and statements at the right time to encourage them, but avoided interfering with participants’ cognitive processes by not commenting on the participants’ ideas or statements. Each interview lasted approximately 30 minutes.

The day after the interview, we transcribed the notes and recordings word-by-word in a careful, accurate, and comprehensive manner, and marked all silent language signals (such as silence, pauses, and laughter) in the written transcription to ensure accuracy. We obtained 16 interview records.

Data analysis

We used constructivist grounded theory (CGT) to analyse the semi-structured interview data. CGT facilitates exploring open-ended responses while minimising bias and assumptions and recognises the researchers’ role in the research process (Charmaz, 2006). CGT has been used by researchers to explore students’ perceptions of critical thinking (Bowen, 2022; Wan et al., 2023) and translational organic chemistry (Flaherty, 2020). Based on the CGT analytical process (Charmaz, 2006; Corbin and Strauss, 2015; Creswell and Poth, 2017), we conducted multiple stages of open coding, focused and axial coding, and theoretical coding to develop a narrative interpretation framework for pre-service chemistry teachers’ climate change knowledge.

Reliability and validity

Qualitative research uses a step-by-step validation process that checks, confirms, identifies, and determines data to ensure the study's reliability, validity, and vigour. We followed the strategy Morse et al. (2002) established to assess reliability and validity in qualitative research. The research process involves (1) selecting an appropriate research methodology to ensure that it matches the data and analysis procedures; (2) randomly sampling participants within representative school segments; (3) collecting and analysing the data simultaneously, and reconfirming ideas generated from the data with newly collected data; (4) developing a theory between the microdata perspective and the macro concept/theoretical understanding based on the theory developed from the original data, where the generated theory serves as a template for comparison and further theory development; (5) endeavouring to be responsive, open, sensitive, creative, and insightful throughout the interview process, and willing to abandon any unsupported ideas.

To ensure the reliability and validity of this study, four professors, two from the field of teacher education and two from the field of chemical science, were invited to provide guidance on the study's methodology, outline of the semi-structured interviews, research process, and analysis. Timely modifications to the study were made based on the recommendations of the four experts.

Results and discussion

Pre-service chemistry teachers’ overall understanding of climate change

We found that, overall, all participants had an understanding of climate change and its related knowledge. The 16 pre-service chemistry teachers were familiar with the term climate change and considered themselves to be highly aware of this international subject. They mentioned that they often came across relevant content about climate change on the TV news, Internet videos, WeChat public platform, Sina hot search, or documentaries. In addition, some participants also mentioned that their experiences in university and the community helped them to gain a deeper understanding of climate change. For example, PCT-S-02 mentioned ‘participating in climate change community activities and access to climate change lecture reports’. PCT-S-06 participated in Model United Nations debates, and PCT-F-07 mentioned ‘visiting science and technology museums and other museums’.

During the interviews, nearly all participants mentioned the greenhouse effect, global warming, the ozone hole, and other phenomena related to climate change. Some participants mentioned the influence of rising sea levels, the famous ‘El Niño’ phenomenon, the Antarctic glacier melting, and the loss of polar bears’ habitat. For example, PCT-F-04 noted that ‘I have watched documentaries about polar bears being displaced due to melting Arctic ice’. These results suggest that pre-service chemistry teachers have a certain overall understanding of climate change based on their existing knowledge and experience. This finding is consistent with that of previous studies (Varela et al., 2020).

We found that both freshman and senior pre-service chemistry teachers had a reasonable understanding of the meaning of climate change. Although they could not provide a precise definition of climate change, they could explain it from certain perspectives. All participants mentioned temperature as a climate change indicator, and two mentioned precipitation. For example, PCT-S-02 mentioned that ‘climate change can be measured by some of the indicators used to measure weather, such as temperature and precipitation’.

Pre-service chemistry teachers’ understanding of climate change manifestations

(1) Confusion between climate change, global warming, and the greenhouse effect. Previous research found that college students tend to confuse concepts related to the greenhouse effect and global warming (Versprille and Towns, 2015). This is consistent with our findings. Regarding the relationship between climate change and global warming, four participants believed that ‘global warming is the cause of climate change’, six believed that ‘global warming is a manifestation of climate change’, and another six believed that ‘global warming and climate change have a subordinate relationship’. Regarding the relationship between climate change and the greenhouse effect, eight participants believed that ‘the greenhouse effect is a cause of climate change’, two believed that ‘the greenhouse effect and climate change have a subordinate relationship’, four believed that ‘the greenhouse effect is a manifestation of climate change’, and two believed that ‘the two terms mean the same thing’. Additionally, most participants thought that methods for mitigating climate change and the greenhouse effect were similar.

Only four senior pre-service chemistry teachers could identify the relationship between climate change, global warming, and the greenhouse effect, while the other 12 were not clear about the difference. This suggests that most pre-service chemistry teachers have a vague or even incorrect understanding of climate change, global warming, and the greenhouse effect and the relationships between them, and confuse the three concepts to a large extent. However, four senior pre-service chemistry teachers understood the concept well, suggesting that university course learning facilitates students’ understanding of climate change.

(2) Pre-service chemistry teachers adequately understand global warming's root causes, and the seniors know more than the freshmen. All participants mentioned that ‘the increase in CO₂ content leads to global warming’ and provided examples from a chemistry perspective that some human behaviours, such as automobile emissions, coal burning, straw burning, and industrial exhaust emissions from factories, may lead to global warming. For example, PCT-F-02 believed that ‘CO₂, SO₂, CO, and other gases produced by coal combustion lead to global warming’; PCT-S-03 pointed out that ‘with the development of the economy, automobile exhaust emissions have increased greatly; there are also harmful gases such as SO₂produced by human mining and processing combustion; gases such as CO₂produced by straw combustion will damage the atmosphere and lead to climate warming’. These findings suggest that all pre-service chemistry teachers appropriately understand global warming's root causes and the corresponding chemical behaviour, and that the seniors have a richer and more comprehensive understanding than the freshmen.

(3) Pre-service chemistry teachers have a certain understanding of the source of acid precipitation. Students can analyse acid precipitation's harm to buildings from a chemical perspective but cannot analyse its harm to soil in combination with soil elements.

Regarding acid precipitation sources, participants explained the sources and mechanisms of sulphuric and nitric acid precipitation. All of the pre-service chemistry teachers had a good understanding of sulphuric acid precipitation sources and their chemical reactions and could correctly write the chemical equation for a sulphuric acid precipitation reaction. Among them, PCT-F-06, PCT-S-03, and PCT-S-05 wrote the answer, ‘S + O₂ = SO₂SO₂ + H₂O = H₂SO₃2H₂SO₃ + O₂ = 2H₂SO₄or 2SO₂ + O₂ = 2SO₃SO₃ + H₂O = H₂SO₄’ listing two reactions for sulphur dioxide, while the rest listed only one. Fourteen pre-service chemistry teachers believed that the main source of sulphuric acid precipitation was burning coal, while only PCT-F-03 and PCT-F-06 believed that it involved factory exhaust emissions. However, pre-service chemistry teachers had a limited understanding of nitric acid precipitation sources and their chemical reaction equations. The seniors could give examples of nitric acid precipitation causes, such as automobile exhaust emissions and nitrogen fertiliser use. Six seniors could write the nitric acid precipitation reaction equation; for example, PCT-S-05 wrote the equation, ‘N₂ + O₂ = 2NO 2NO + O₂ = 2NO₂3NO₂ + H₂O = 2HNO₃ + NO’. However, the freshmen did not understand much about it. Regarding measures to reduce acid rain, participants provided examples from the sulphur element perspective to reduce coal combustion, treat exhaust gas to reduce harmful gases such as SO₂, implement desulphurisation treatment for coal, and use alternative energy. In general, the senior pre-service chemistry teachers knew more about acid precipitation and offered more suggestions for the prevention and control of acid precipitation than the freshmen.

Regarding the harm caused by acid precipitation, most participants mentioned ‘the harm to buildings and plant growth’. For example, PCT-S-01 thought that ‘acid precipitation can corrode buildings and crops, and then have a great impact on human beings’, and she wrote an equation for the reaction of the main components of a building with acid rain, ‘CaCO₃ + 2H⁺ = Ca²⁺ + H₂O + CO₂↑’. Meanwhile, PCT-S-07 mentioned the corrosion of steel frames: ‘for example, there are some common steel frames nowadays, which are mainly composed of iron, and iron and sulphuric acid will undergo a substitution reaction, which will cause corrosion of this steel and may make the building unstable’. This shows that pre-service chemistry teachers explain the interaction between acid rain and building materials in detail. Regarding soil corrosion by acid rain, participants could only suggest that ‘high acidity is bad for plant growth’, but they were unclear about the soil elements and how they react with acid rain.

(4) Pre-service chemistry teachers have a certain understanding of the ozone layer and can describe the role of the ozone layer and the substances that destroy it. All participants had a certain understanding of ozone layer depletion. The freshman pre-service chemistry teachers were taking the inorganic chemistry course, which included this topic, so they explained ozone in more detail; all the senior pre-service chemistry teachers mentioned that they had learned about it in college textbooks. For example, regarding an ozone layer formation mechanism, PCT-F-04 could accurately say, ‘ozone is the decomposition of ultraviolet radiation into oxygen atoms, which are unstable and form ozone with oxygen’, while PCT-S-03 analysed ozone in more depth based on physical and structural chemistry knowledge and mentioned that ‘the oxygen–oxygen bonding level in ozone is 1.5, which is supposed to be formed with oxygen radicals’. Regarding ‘how to measure the ozone content’, freshman pre-service chemistry teachers responded based on acquired knowledge; for example, PCT-F-02 said, ‘we can measure ozone by measuring ultraviolet light’, and PCT-F-06 said, ‘it can be detected by using some reducing agents to make use of the oxidation of ozone’. PCT-F-04 also indicated that they had just learned the corresponding chemical equation. All the senior pre-service chemistry teachers indicated that they had learned this information previously, but could not immediately recall it.

Regarding the role of the ozone layer and the substances that destroy it, all participants knew that it protects against ultraviolet rays and that freon is a destructive substance. The senior pre-service chemistry teachers provided more detailed explanations compared with the freshman; for example, PCT-S-08 mentioned that ‘the ozone layer can block ultraviolet light from the sun, which can damage human skin and cause diseases such as skin cancer, and if the ozone layer is destroyed, violet light, which is shortwave light, has high energy and can cause more free radicals in the air, which are very unstable and can collide with each other and may aggravate the greenhouse effect’. These findings show that pre-service chemistry teachers have a certain understanding of ozone, its role, and the substances that destroy it. This knowledge is also covered in university textbooks.

Pre-service chemistry teachers’ understanding of climate change causes

(1) Pre-service chemistry teachers are not sufficiently aware of the greenhouse effect's role on the earth and its mechanism of action. Participants did not respond well to questions on ‘the role of the greenhouse effect’ and ‘the mechanism of the greenhouse effect’ in general. Regarding the greenhouse effect's role, only PCT-S-03 and PCT-S-07 mentioned that the greenhouse effect could ‘make human beings live within a normal temperature range’, while other participants mentioned that ‘the greenhouse effect is a harmful phenomenon to human beings’. These results show that most pre-service chemistry teachers confuse ‘the greenhouse effect’ with the ‘intensification of the greenhouse effect’, have heterogeneous ideas regarding ‘the greenhouse effect’ concept, and generally misunderstand it. Regarding the ‘mechanism of the greenhouse effect’, freshman pre-service chemistry teachers mentioned ‘radiation’; for example, PCT-F-01 mentioned that ‘It seems to be longwave radiation or shortwave radiation heating up the ground’ and PCT-F-04 stated, ‘I know the shortwave radiation is under 3 microns, if there's too much shortwave radiation, it should get hotter, but I'm not sure about this answer’. PCT-S-06 mentioned an energy formula learned in college, ‘According to the energy formula E = hc/λ, the wavelength is in the denominator. If the wavelength is short, the energy will increase, and more energy will reach the Earth’, but she lacked knowledge on the emission of long or short wave radiation from the sun. However, no participant could clearly explain the greenhouse effect mechanism.

(2) Pre-service chemistry teachers lack understanding of greenhouse gases; senior pre-service chemistry teachers can better explain the mechanism of greenhouse effect intensification than freshmen. All participants mentioned CO₂ as a greenhouse gas. Three also mentioned NO₂ and SO₂; however, although these gases are harmful, they are not greenhouse gases. Therefore, most pre-service chemistry teachers’ knowledge of greenhouse gases is limited to CO₂, and some mistakenly regarded other harmful gases as greenhouse gases. None of the participants knew that water vapour is the most abundant greenhouse gas on earth, most did not know how CO₂ and other greenhouse gases aggravate the greenhouse effect, and only PCT-S-03 answered that ‘I studied this in college. The increase in CO₂will affect the thickness of the atmosphere, which will lead to the intensification of the greenhouse effect’.

The interview results show that pre-service chemistry teachers do not clearly understand greenhouse gases, except for CO₂. They incorrectly believe that CO₂ is the most abundant greenhouse gas on earth, mistake other harmful gases as greenhouse gases, and do not have a clear understanding of the relationship between greenhouse gases and the greenhouse effect. It is also difficult for pre-service chemistry teachers to understand the greenhouse effect mechanism and the corresponding relationship with increased carbon dioxide concentrations and climate change effects. This has been confirmed in previous studies (Versprille and Towns, 2015). Senior pre-service chemistry teachers have a clearer and deeper understanding of the problems than the corresponding freshman.

(3) Pre-service chemistry teachers have a good understanding of CO₂ and can identify CO₂ sources and locations from a carbon cycle perspective. Regarding CO₂ sources, all participants mentioned that CO₂ is produced by burning fossil fuels or straws, and most noted that some biological behaviours in nature, such as respiration and plant and animal decomposition, can also produce CO₂. Additionally, some participants mentioned automobile exhaust emissions. All participants identified plant photosynthesis as the CO₂ destination. Pre-service chemistry teachers provided reasonable answers regarding the source and location of CO₂ in modern society.

Pre-service chemistry teachers’ understanding of climate change effects

Regarding climate change effects, all participants agreed that the climate is changing, and that climate change will worsen the earth's environment. Four freshman pre-service chemistry teachers suggested that ‘the impact of climate change on daily life is that summer is hotter’. PCT-S-02 mentioned additional impacts, such as floods, dust storms, and haze, while PCT-S-03 gave a long-term answer: ‘I think it is a matter of historical process, which is hard to see in a short period, but it will have a great impact in ten or twenty years’. Regarding the effects of climate change on the earth, participants mentioned sea level rise, glacier melting, biological extinction, global warming, the ozone hole, and extreme climate. These results show that pre-service chemistry teachers have a certain understanding of climate change and believe that climate change is a historical problem that will have more serious consequences for the earth in the future.

Pre-service chemistry teachers’ understanding of how to manage climate change

Regarding mitigating the greenhouse effect by analysing CO₂ sources and destinations, all participants mentioned ways to reduce fossil fuel burning and afforestation to decrease greenhouse effect intensification. Some suggested more solutions; for example, six participants suggested implementing clean or green energy, and eight suggested reducing automobile emissions. PCT-S-05 also mentioned some scientific research initiatives: ‘now many scientists are studying carbon chemistry, metal–organic framework, and other fields, expecting to get a metal–organic framework that can achieve effective adsorption of CO₂, which can be converted into ethanol or some other substances that are beneficial to society’.

Regarding climate change mitigation, most participants recognised human responsibility for climate change, which is consistent with previous research findings (Arto-Blanco et al., 2017). Participants suggested pro-environmental measures, such as using clean energy, energy conservation, reducing energy consumption, and reducing emissions to mitigate climate change. For example, PCT-F-03 proposed that ‘more trees can be planted to make more use of CO₂, and CO₂can be absorbed for synthesis through the design of photocells, to reduce the burning of fossil fuels and automobile exhaust emissions’. PCT-S-08 suggested exhaust treatment: ‘factory emissions are treated, and car exhaust emissions are installed with gas conversion devices so that toxic exhaust gases are converted into non-toxic and harmless gases before they are emitted’. These results show that pre-service chemistry teachers tend to look beyond the simple ‘green life’ solution by proposing more scientific and practical measures to mitigate climate change. Senior pre-service chemistry teachers were better at this than freshmen.

Conclusions

This study obtained some promising results from analysing climate change interview data from pre-service chemistry teachers. We found that these students have a certain understanding of global climate change and its basic meaning. They understand global warming's root causes and illustrate them from the perspectives of chemistry and life. They understand building corrosion caused by acid precipitation combined with some building materials, and senior pre-service chemistry teachers have a better understanding of sulphuric and nitric acid precipitation than freshmen. Pre-service chemistry teachers have a good understanding of the action and depletion of the ozone layer and can explain its formation mechanism and detection methods to a certain extent. They can also explain the source and location of greenhouse gas CO₂ from the carbon cycle perspective and have a full understanding of CO₂. They realise that climate change will impact social development and human life over time and can put forward corresponding scientific and practical solutions; senior-level pre-service chemistry teachers were more adept at this than freshmen.

Although pre-service chemistry teachers have a satisfactory understanding of climate change-related knowledge, the interviews exposed some shortcomings. Some pre-service chemistry teachers hold incorrect models of climate change, which hinder their understanding of how and why climate change occurs (Zangori et al., 2017). First, some pre-service chemistry teachers confuse climate change, global climate warming, and the greenhouse effect, and these incorrect concepts were not eliminated through their university studies. Second, pre-service chemistry teachers have a limited understanding of nitric acid precipitation and cannot analyse or explain the harm caused by acid precipitation combined with soil elements. Third, although pre-service chemistry teachers have a certain understanding of the ozone layer, they are not clear about its depletion mechanism (Howard et al., 2013). Understanding ozone formation and depletion mechanisms is crucial for better ozone layer protection. Fourth, pre-service chemistry teachers do not have a good understanding of the greenhouse effect and global warming (Jakobsson et al., 2009), or of the greenhouse effect's mechanisms and impact on the earth. The chemical factors involved in these mechanisms, such as electromagnetic radiation and substances’ particulate properties, facilitate the understanding of relevant knowledge and strengthen the connection between theoretical knowledge and practical life. Fifth, pre-service chemistry teachers have an insufficient understanding of greenhouse gases. The study participants could only name CO₂ as a greenhouse gas; most did not know that CO₂ intensifies the greenhouse effect. Participants also did not have a good understanding of how and why carbon moves (Zangori et al., 2017).

Our analysis identified the main factors that affect pre-service chemistry teachers’ understanding of climate change. First, senior-level pre-service chemistry teachers have a more scientific and in-depth understanding of many climate change-related aspects compared with freshman-level pre-service chemistry teachers. This suggests that college courses, especially chemistry-related courses, greatly impact the pre-service chemistry teachers’ cognition and understanding of climate change (Zhao and Ewert, 2021). This indicates that studying relevant knowledge in college chemistry courses positively affects pre-service chemistry teachers’ understanding of climate change issues. Participants repeatedly mentioned climate change knowledge in college chemistry courses during the interviews. For example, the explanation of ozone in the freshman inorganic chemistry course provides pre-service chemistry teachers a deeper understanding of ozone layer-related issues. Studies have also shown that relevant course work improves college students’ understanding of climate change (Carman et al., 2021; Aksit et al., 2018).

Second, science popularisation, supported by information technology, affects climate change knowledge. Information technology's various media and network resources occupy people's lives. Most pre-service chemistry teachers expressed during the interviews that they learned some information and trends about climate change from watching the news, videos, and related documentaries. Gaining knowledge from popular science, supported by information technology, is an important avenue for students to acquire climate change knowledge. Today's college students experience more exposure to climate change through school and the media than previous generations (Aksit et al., 2018). With information technology's rapid development, science communication continues to develop. As a kind of public welfare social education resource, popular science is increasingly important for improving citizens’ scientific literacy.

Third, pre-service chemistry teachers’ dual identity affects their experience and understanding of the climate change theme. Some pre-service chemistry teachers’ college experiences influenced their knowledge and understanding of climate change—for example, participating in climate change community activities, listening to climate change lecture reports, and participating in debates on topics related to climate change. Additionally, as social citizens, pre-service chemistry teachers are widely active in various social organisations and places, such as visiting science and technology museums and other museums. The dissemination of climate change knowledge in these places will affect pre-service chemistry teachers’ understanding of climate change. This reflects the importance of informal learning on pre-service chemistry teachers’ development (Heider et al., 2022).

Implications and limitations

We must acknowledge that our interpretations are our own and are based on the specific context of our qualitative research. The constructivist grounded theory recognises that a researcher's themes and subsequent theories or frameworks are co-constructed with participants. Thus, the investigator will have had some influence on the research process. However, as previously mentioned, we tried our best to ensure our study's reliability and effectiveness for precise results.

Our findings show that, although pre-service chemistry teachers have a certain understanding of climate change's global social science issue, they still have a vague or even incorrect understanding of some conceptions, which need to be strengthened and improved. Higher education plays an important role in providing future citizens and leaders with the ability to address systemic issues behind complex problems such as climate change (Liu, 2022). Chemical science plays an important role in solving climate change-related issues. Chemistry curriculums should strengthen their teaching of global climate change (Wan and Bi, 2020), and develop pre-service chemistry teachers’ ability to thoroughly and accurately explain the greenhouse effect, acid precipitation, ozone layer, and other related mechanical issues from a micro perspective; consider climate change's performance and causes from a macro and meso level; reflect on the impact of climate change; and identify ways to manage it and related issues from the perspective of future social development and human survival.

As modern society and information technology continue to develop, scientific communication and climate change popularisation, coupled with climate change attention in non-formal education, should be strengthened to improve pre-service chemistry teachers’ awareness and understanding of climate change from multiple levels and perspectives, enhance their scientific literacy and humanistic concern, improve their sense of social responsibility and mission, and reserve human power for a response and solution to climate change and the cultivation of future social citizens.

Conflicts of interest

There are no conflicts to declare.

Appendix

Appendix 1. Interview outline

1. Overall understanding of global climate change

(1) Have you heard about climate change? Please explain your understanding and thoughts about it.

2. The main manifestations of climate change

(1) Have you heard about global warming? Do you think it is related to climate change? If so, please elaborate on their relationship.

(2) What do you think is the root cause of global warming? Can you explain human actions that cause global warming from a chemical perspective?

(3) What are the types of acid rain? Can you explain the source and cause of acid rain? What chemical reaction occurs when it is combined with elements such as sulphur and nitrogen?

(4) What are the harmful effects of acid rain? What is the possible damage that can be caused to buildings when acid rain combines with building materials? Can you explain the harm caused by acid rain to the soil when it combines with its elements?

(5) Have you heard about the ozone layer? Can you explain the mechanism of ozone layer formation from a chemical or microscopic perspective?

(6) Ozone holes have appeared on the earth today. Can you explain the role of the ozone layer on earth from a microscopic point of view? Do you know how to measure the ozone content?

(7) At present, the ozone layer is facing a risk of continuous depletion. Can you give examples of substances that destroy the ozone layer? Can you explain the chemical mechanism causing the destruction of the ozone layer?

3. The causes of climate change

(1) Do you think the climate on earth is changing? If so, what do you think is the cause of climate change?

(2) Do you know the role of the greenhouse effect? The increase in greenhouse effect has led to many adverse effects. What do you think are the reasons behind the increase in the greenhouse effect?

(3) Have you heard of greenhouse gases? What are the greenhouse gases you know about? Which is the primary greenhouse gas on earth?

(4) Can you elaborate on how greenhouse gases such as carbon dioxide exacerbate the greenhouse effect?

(5) Can you list the main sources of greenhouse gases such as carbon dioxide? How can we mitigate the increase in the greenhouse effect from the carbon cycle perspective?

(6) According to you, what is the relationship between the greenhouse effect and climate change?

4. The impact of climate change

Do you think climate change can affect our daily lives? Does it have an impact on earth? Please provide a few detailed examples.

5. How to deal with climate change

(1) What measures do you suggest to prevent and control the increasing greenhouse effect?

(2) Climate change has numerous adverse effects on the planet. Can you propose some methods that you think could mitigate or decelerate these effects?

Acknowledgements

This research was sponsored by a Ministry of Education Youth Project of the National Education Sciences Planning Foundation of China project, which is entitled Research on the Role Reconstruction of Primary and Secondary School Teachers in the Age of Artificial Intelligence (EHA220540).

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