Eco-fertility: examining the climate change-total fertility rate nexus in the context of sustainable developmental goals in a systematic review approach

Climate change and TFR nexus

Over the past decade, a growing body of research has illustrated the intricate relationship between climate change and fertility, both in humans and animals [27], 28]. Studies from past decade, such as the 2014 investigation into the determinants of sperm DNA methylation levels, highlighted geographical variations in methylation, potentially serving as a biomarker in fertility studies [11]. By 2019, the conversation had expanded to emphasize the significant roles reproductive sciences play in human health, livestock production, and environmental management [29]. The intersection of these fields can shape global policies to address issues exacerbated by climate change [12].

The subsequent years continued to underscore the importance of understanding the role of the environment in fertility. For instance, a 2020 study showcased the implications of ocean pollution on human health, marking the perils posed by land-based pollutants to marine life and humans alike [13]. The same year, researchers probed into the potential influence of climate change on the timing of menarche in women, suggesting that climate-related disturbances might affect long-term health of women [14].

By 2021, the narrative shifted to a comprehensive exploration of various environmental threats to reproductive health. Notably, studies started to consistently highlight the detrimental effects of industrial toxins, pollutants, and other climate change outcomes on reproductive health [15]. Sperm quality, often regarded as a crucial parameter in fertility studies, was found to be compromised by environmental and occupational pollutants [17]. A systematic review in 2022 further emphasized the threats that rising temperatures pose to reproductive health, pointing to challenges like pollution, wildfires, and vector-borne diseases, which directly affect fertility and obstetric outcomes [18]. Meanwhile, in 2023, research reiterated the vulnerabilities of pregnant women and children to climatic and environmental changes, emphasizing the repercussions of these changes on maternal and newborn health [19]. Concurrently, the Minderoo-Monaco Commission delved into the multifaceted issue of plastics, underscoring the potential detrimental impact of plastics to human health, including reproductive wellness. The report delineates concerns stemming from unsustainable plastic practices leading to environmental degradation, health hazards, and societal inequities. There is an expressed urgency for global action, predominantly against the pervasive use of single-use plastics, given their environmental accumulation and consequent threats [20].

Turning our attention to animal reproduction, the investigation of fertility, particularly in the context of external stressors such as climate change and endocrine-disrupting chemicals (EDCs), has garnered increasing attention and concern. In 2015, a paper explored the potential effects of hormone-disrupting substances on the reproductive and developmental processes of wild amphibians. Although evidence was presented indicating the influence of EDCs on amphibians, there was an ambiguous link between these chemicals and direct repercussions on amphibian fertility and reproduction. This underscores the need for refined methodologies and comprehensive research frameworks to conclusively ascertain the hazards posed by EDCs [22]. Simultaneously, in the same year, research highlighted a significant transition within the dairy cattle breeding sector. Traditionally, the primary breeding objective in the dairy sector was focused on milk yield. However, the 2015 study depicted an evolutionary shift prioritizing not only productivity but also sustainable and functional traits, driven by both health and ecological considerations. The adoption of advanced techniques, such as mid-infrared spectroscopy for trait assessment, was advocated as a progressive approach [23]. Moreover, in 2021, a study on sustainable dairy farming with a distinctive spotlight on South Africa, accentuated the need to reconfigure dairy breeding goals and championed the integration of genomic data, positing its potential to bolster both cow well-being and sustainable dairy production [25].

Our literature search has also found studies that specifically emphasized several challenges introduced by climate change, notably the implications of heat stress on dairy cow fertility [21], 30]. A 2020 paper unambiguously identified global warming as a formidable challenge for dairy farming, accentuating the adverse effects of heat stress on bovine fertility, predominantly in tropical zones. This was linked to factors like hyperthermia, oxidative stress, and associated physiological alterations resulting from elevated temperatures [24]. In 2023, a study delved into the systemic physiological adaptations in dairy cattle arising from heat stress, and an exhaustive analysis provided perspectives on how shifts in metabolic processes could influence reproductive outcomes [21]. Infertility in cattle not only causes significant economic loss but also exacerbates climate change [31], 32]; more cattle are needed to meet global protein demands, increasing greenhouse gas emissions. The Northeast Multistate Project has extensively studied ovarian processes in ruminants, enhancing understanding of “maternal recognition of pregnancy”. The study highlighted the regulation of the ruminant corpus luteum, revealing roles of prostaglandins and immune cells in fertility. Such insights can guide future climate-friendly fertility research, promoting sustainable livestock production [26].

Thus, the trend in publications on climate change and fertility reflects an evolving understanding of the profound impact of environment upon reproductive health. This understanding underscores the urgency of implementing multidisciplinary solutions to safeguard both human and animal reproductive health in the face of a changing climate.

Climate change TFR: comprehensions and future perspectives

Climate change is prominently transforming the global ecosystem, exerting profound effects on both natural and anthropogenic systems [33] (Figure 2). Such alterations exert both direct and indirect effects on the determinants of TFR, denoting the mean number of offspring a female is projected to produce during her lifespan [34]. Resource scarcity is one of the major challenges. Environmental changes prompted by climate fluctuations, like extended droughts or alterations in precipitation regimes, can lead to diminished access to crucial resources [35]. As a result, in many societies that value large families for their agricultural or economic contributions, a decreased resource base might indirectly promote increased reproductive rates. Moreover, migration and displacement are another concern. The amplification in the intensity and frequency of climatic disturbances is compelling populations to relocate, and the adverse conditions associated with such migrations often have a positive correlation with heightened fertility rates. These demographic transitions present significant challenges for governmental bodies in ensuring appropriate healthcare, education, and other vital services [36]. Additionally, the escalation in the prevalence of vector-transmitted diseases, undernutrition, and related health risks due to climate transformations can also impact reproductive behaviors. In locales where the mortality rate of children is elevated due to these issues, families may opt to birth more offspring, foreseeing that a portion might not reach maturity [37].

Figure 2:

Interplay among climate change, sustainable development goals (SDGs), and total fertility rate (TFR). This figure highlights the impact of climate change factors, namely increased temperatures, rising sea levels, and extreme weather events. These factors directly affect SDG 13 (climate action) and consequently influence SDG 1 (poverty), SDG 3 (good health and well-being), SDG 4 (quality education), and SDG 5 (gender equality). The SDGs may ameliorate the impact of climate changes on the TFR determinants, influencing birth rates, overall population growth, and shifting age demographics, while the related.

TFR and SDGs: implications and measures

The intricate relationship between TFR and the SDGs is significantly influenced by climate change, which impacts fertility patterns through factors such as agricultural failure, water scarcity, and disaster-driven displacement [38]. As economic and environmental uncertainties prompt families to have fewer children, lowering fertility rates, it becomes crucial to integrate responses with specific SDGs to mitigate these effects (Table 2). For instance, climate-induced poverty can influence family planning decisions, necessitating strategies under Goal 1 (No Poverty) to enhance economic resilience and support sustainable family planning [39]. Similarly, environmental changes can strain healthcare systems under Goal 3 (Good Health and Well-being), impacting reproductive health services and necessitating comprehensive healthcare access [40]. In the face of changing climate and declining TFR, there is need for proper family planning so as to allow significant investment in each child’s education, aligning with Goal 4 (Quality Education) to ensure universal access to quality education [41]. Finally, the pressures of climate change offer a pivotal moment to advance Goal 5 (Gender Equality) by empowering women in decision-making including family planning, thus challenging traditional roles and expanding opportunities [42]. These adaptive strategies underscore the need for proactive policy and planning to address the interlinkages between climate change, fertility, and sustainable development.

Appreciating the interrelatedness of climate change, TFR and SDGs empower us to develop holistic approaches. Recommended measures encompass enhancing climate resilience, empowering women, strengthening health infrastructure, promoting sustainable agricultural practices, educational outreach and integrated policies. In this context, it is imperative for governments and institutions to allocate resources towards adaptive measures, ensuring communities can effectively cope with challenges instigated by climate fluctuations [43]. This, in turn, can equilibrate fertility rates. Potential adaptive measures include the establishment of sustainable water systems, advancement in agrarian methodologies, and the development of durable infrastructure [44]. Moreover, rectifying gender imbalances is of utmost importance. Ensuring equitable access to education and job opportunities for women frequently results in preferences for smaller family sizes. Enhancing access to family planning tools and education on reproductive health further facilitates well-informed choices concerning family dimensions [45]. Furthermore, augmenting access to high-caliber healthcare, with an emphasis on maternal and child well-being, is crucial to mitigate high child mortality rates and the consequent elevated TFRs [46]. Also, in light of the correlation between TFR and agricultural output in numerous societies, transitioning to ecologically sustainable agricultural methodologies can guarantee consistent crop yields, thereby reducing the necessity for expansive families as agricultural labor [47]. It is also essential for communities to be cognizant of the enduring advantages of sustainable reproductive planning within the framework of a shifting climatic paradigm. Educational initiatives are instrumental in reshaping societal perspectives on optimal family dimensions [48]. Finally, policymaking should account for the intertwined dynamics of climate alteration, TFR, and SDGs. A comprehensive approach ensures that initiatives in one sphere augment, rather than impede, aims in another.