Microplastics are polymer-based materials. Their primary structural framework is composed of carbon. They are categorized into primary microplastics, intentionally manufactured at sizes smaller than 5 mm (such as microbeads in cosmetics and industrial products), and secondary microplastics, which result from the breakdown of larger plastics through photodegradation, mechanical stress, and microbial activity.1
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The widespread presence of microplastics in the environment is a consequence of improper plastic waste management and the continuous rise in global plastic production, which increased from 1.3 million tons in 1950 to 359 million tons in 2018. Projections estimate that total plastic waste will reach 634 million tons by 2025.2,3
Climate change amplifies the environmental impact of microplastics by affecting their degradation, distribution, and interactions within ecosystems. Microplastics affect various environmental compartments, including the pedosphere (soil), hydrosphere (water bodies), and the atmosphere. These small particles are more easily ingested by aquatic organisms and plants, causing toxic effects such as oxidative stress, impaired metabolism, and disrupted gene expression.4
Once in aquatic ecosystems, microplastics tend to remain and accumulate, resulting in a growing pervasiveness and steady increase in microplastic concentrations across the world’s rivers, lakes, and oceans.
Nathanial Banks, Co-Founder and CTO, PolyGone Systems
Impact of Temperature
Rising global temperatures significantly influence the breakdown of microplastics by accelerating thermal degradation, which weakens the plastic structure and promotes fragmentation into smaller particles. Elevated temperatures also expedite the degradation of plastics during transport through runoff into freshwater and marine environments.2,5
Studies have shown that melting glaciers, rainfall, and non-glacial runoff contribute to the redistribution of microplastics. For instance, it is estimated that up to one trillion microplastic particles could be released into the Arctic Ocean within a decade due to ice melting.6
Additionally, glacial retreat in regions like the Tibetan Plateau and Svalbard releases lightweight microplastics into lakes and rivers, while annual freeze-thaw cycles fragment them further into nanoplastics, which disrupt soil biogeochemical cycles by infiltrating deep soil layers and groundwater.5, 7
In tandem with rising temperatures, increased UV radiation resulting from climate change plays a crucial role in the degradation of plastics. UV radiation enhances photodegradation, breaking down plastics into microplastics more efficiently in both marine and terrestrial environments.8
The combined effect of higher temperatures and UV exposure accelerates the fragmentation of plastic waste, releasing a higher abundance of microplastics into ecosystems. This process is particularly evident in aquatic environments, where plastics exposed to sunlight and UV radiation degrade faster. As a result, more microplastics are introduced into water bodies, increasing their concentration and impacting aquatic life.8,9
UV-induced degradation is also influenced by environmental factors such as water salinity, wave action, and sediment composition, further affecting the breakdown rates of microplastics.8
Changes in Environmental Conditions
Extreme Weather Events
Extreme weather events, such as storms, floods, and hurricanes, significantly influence the breakdown and redistribution of microplastics in both terrestrial and aquatic environments. These events intensify the movement of plastic debris, exposing them to physical forces that enhance fragmentation into microplastics and nanoplastics.2,10
Shifting ecosystems caused by climate change, such as glacial retreat, rising sea levels, and altered seasonality, further amplify microplastic distribution. In polar regions, microplastics accumulate in sea ice and sediments, which are consumed by marine organisms like seabirds and fish. The melting of sea ice, driven by warming temperatures, releases microplastics into surrounding waters, affecting fragile ecosystems.10
For example, reduced ice cover leads to a decline in ice algae populations, disrupting the food chain from zooplankton to higher trophic levels, including Arctic cod and polar bears. Similarly, shifting terrestrial ecosystems experience altered soil parameters due to the persistence of plastics, affecting nutrient cycles, soil fertility, and biodiversity.10
Ocean Acidification and pH Changes
Climate change-induced ocean acidification, caused by increased carbon dioxide absorption, alters the pH levels of aquatic environments, impacting the interaction and breakdown of microplastics. The acidic conditions can change the surface properties of microplastics, making them more prone to adsorbing toxic chemicals and microorganisms. This creates a complex vector for harmful substances to enter marine ecosystems, threatening aquatic organisms.11
Altered pH levels also impact the bioavailability and ingestion of microplastics by marine organisms. A recent review by Sunil et al. (2024) reported that microplastics can interfere with the photosynthetic efficiency of phytoplankton, which are essential carbon-fixing organisms. This disruption reduces their ability to sequester carbon dioxide, contributing to a feedback loop of increased atmospheric carbon levels.10
In freshwater systems, acidified conditions may accelerate the weathering of microplastics, increasing their fragmentation and mobility and further spreading contamination to remote regions.
Microbial Activity and Climate Change
Temperature variations and shifts in ecosystems driven by climate change profoundly influence microbial activity, including the degradation of microplastics. Elevated temperatures can enhance microbial metabolic rates, thereby accelerating the enzymatic breakdown of plastic polymers into smaller fragments.12
For instance, a study by Park and Kim (2019) has demonstrated that certain microbial strains, such as Bacillus and Pseudomonas, exhibit higher plastic degradation efficiencies at elevated temperatures. A strain like Bacillus borstelensis can degrade low-density polyethylene (LDPE) more effectively at 50 °C, indicating that temperature can act as a catalyst for microbial degradation processes.13
Ecosystem shifts, such as those caused by glacial retreat, flooding, or changing soil compositions, also influence microbial activity by altering the availability of plastic debris and the composition of microbial communities. For instance, in landfill and soil environments, anaerobic microbial activity predominates, leading to slower but continuous plastic degradation.11
Climate change can lead to significant alterations in microbial community structures, potentially enhancing or impeding their ability to degrade microplastics. For example, higher temperatures and altered precipitation patterns may foster the proliferation of thermophilic and extremophilic microbial species that are more adept at degrading plastics.11
Microbial communities often function synergistically; mixed microbial strains, such as combinations of Bacillus cereus, Pseudomonas sp., and Rhodococcus sp., have shown higher degradation efficiencies compared to single strains, provided their interactions are not competitive.14
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Challenges and Future Research
Predicting microplastic degradation in changing climates is challenging due to complex interactions between environmental variables and plastic behavior. Factors like rising temperatures, ocean acidification, and extreme weather disrupt degradation processes, while variations in plastic composition and diverse conditions, from polar freeze-thaw cycles to eutrophic lake sediment resuspension, complicate modeling.2
Additionally, the lack of long-term studies limits our understanding of how these factors interact over time, particularly in remote or fragile ecosystems newly exposed to microplastic pollution.2
Future research should prioritize investigating how climate variables influence microplastic degradation and dispersion, focusing on the effects of rising temperatures, ocean acidification, and extreme weather on plastic fragmentation and redistribution. Efforts must also address the development of innovative mitigation strategies, including biodegradable alternatives, advanced recycling technologies, and microbial degradation methods.15
Interdisciplinary research linking climate science, environmental chemistry, and policy, supported by laboratory and real-world studies, is essential for crafting scalable solutions to mitigate the compounded impacts of climate change and microplastic pollution.15
The Impact of Microplastic Pollution on Climate Change
Microplastics and climate change
References and Further Studies
1. Li, K.; Du, L.; Qin, C.; Bolan, N.; Wang, H.; Wang, H. (2024). Microplastic Pollution as an Environmental Risk Exacerbating the Greenhouse Effect and Climate Change: A Review. Carbon Research. https://link.springer.com/article/10.1007/s44246-023-00097-7
2. Haque, F.; Fan, C. (2023). Fate of Microplastics under the Influence of Climate Change. Iscience. https://www.cell.com/iscience/fulltext/S2589-0042(23)01726-1?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2589004223017261%3Fshowall%3Dtrue
3. Shanmugam, V.; Das, O.; Neisiany, RE.; Babu, K.; Singh, S.; Hedenqvist, MS.; Berto, F.; Ramakrishna, S. (2020). Polymer Recycling in Additive Manufacturing: An Opportunity for the Circular Economy. Materials Circular Economy. https://www.researchgate.net/profile/Vigneshwaran-Shanmugam/publication/345307393_Polymer_Recycling_in_Additive_Manufacturing_an_Opportunity_for_the_Circular_Economy/links/5fa448f0458515157becc21e/Polymer-Recycling-in-Additive-Manufacturing-an-Opportunity-for-the-Circular-Economy.pdf
4. Guo, J.-J.; Huang, X.-P.; Xiang, L.; Wang, Y.-Z.; Li, Y.-W.; Li, H.; Cai, Q.-Y.; Mo, C.-H.; Wong, M.-H (2020). Source, Migration and Toxicology of Microplastics in Soil. Environment international. https://www.sciencedirect.com/science/article/pii/S0160412019325097
5. Chen, X.; Huang, G.; Gao, S.; Wu, Y. (2021). Effects of Permafrost Degradation on Global Microplastic Cycling under Climate Change. Journal of Environmental Chemical Engineering. https://www.sciencedirect.com/science/article/abs/pii/S2213343721009775?via%3Dihub
6. Obbard, RW.; Sadri, S.; Wong, YQ.; Khitun, AA.; Baker, I. (2014). Thompson, R. C., Global Warming Releases Microplastic Legacy Frozen in Arctic Sea Ice. Earth's Future. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014EF000240
7. Horton, AA.; Walton, A.; Spurgeon, DJ.; Lahive, E.; Svendsen, C. (2017). Microplastics in Freshwater and Terrestrial Environments: Evaluating the Current Understanding to Identify the Knowledge Gaps and Future Research Priorities. Science of the total environment. https://www.sciencedirect.com/science/article/abs/pii/S0048969717302073
8. Zhang, K.; Hamidian, AH.; Tubić, A.; Zhang, Y.; Fang, JK.; Wu, C.; Lam, PK. (2021). Understanding Plastic Degradation and Microplastic Formation in the Environment: A Review. Environmental Pollution. https://pubmed.ncbi.nlm.nih.gov/33529891/
9. Gewert, B.; Plassmann, MM.; MacLeod, M. (2015) Pathways for Degradation of Plastic Polymers Floating in the Marine Environment. Environmental science: processes & impacts. https://pubs.rsc.org/en/content/articlelanding/2015/em/c5em00207a
10. Sunil, S.; Bhagwat, G.; Vincent, SGT.; Palanisami, T. (2024). Microplastics and Climate Change; the Global Impacts of a Tiny Driver. Science of The Total Environment. https://www.sciencedirect.com/science/article/abs/pii/S0048969724043080
11. Lin, Z.; Jin, T.; Zou, T.; Xu, L.; Xi, B.; Xu, D.; He, J.; Xiong, L.; Tang, C.; Peng, J. (2022). Current Progress on Plastic/Microplastic Degradation: Fact Influences and Mechanism. Environmental Pollution. https://pubmed.ncbi.nlm.nih.gov/35304177/
12. Guzzetti, E.; Sureda, A.; Tejada, S.; Faggio, C. (2018). Microplastic in Marine Organism: Environmental and Toxicological Effects. Environmental toxicology and pharmacology. https://pubmed.ncbi.nlm.nih.gov/30412862/
13. Park, SY.; Kim, CG. (2019). Biodegradation of Micro-Polyethylene Particles by Bacterial Colonization of a Mixed Microbial Consortium Isolated from a Landfill Site. Chemosphere. https://pubmed.ncbi.nlm.nih.gov/30721811/
14. Pérez-García, P.; Danso, D.; Zhang, H.; Chow, J.; Streit, WR. (2021). Exploring the Global Metagenome for Plastic-Degrading Enzymes. Methods in Enzymology. https://pubmed.ncbi.nlm.nih.gov/33579401/
15. Sharma, S.; Sharma, V.; Chatterjee, S. (2023). Contribution of Plastic and Microplastic to Global Climate Change and Their Conjoining Impacts on the Environment-a Review. Science of the total environment. https://pubmed.ncbi.nlm.nih.gov/36889403/
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