Climate Change and Ecological Risk

Background

This mini-lecture, explores the relationship between climate change and chemical pollution. Far from being independent issues, these two drivers of biodiversity loss interact in ways that significantly alter environmental risk profiles.

Climate Projections and Chemical Use

Using Representative Concentration Pathways (RCPs), the Met Office predicts that the UK will transition towards warmer temperatures, drier summers, and wetter winters by the end of the 21st century. These shifts directly influence drivers of chemical usage. For instance, increased solar radiation increases the use of UV-filters and pharmaceuticals (such as chemotherapy drugs and cortisone creams), while changing pest pressures in agriculture require new pesticide regimes. Furthermore, extreme weather events resulting in wildfires increase the environmental load of chemicals in firefighting foams.

Fate, Transport, and Environmental Exposure

Climate change modifies the environmental exposure of chemicals by influencing degradation, deposition, transport and transformation process. Rising temperatures can accelerate biodegradation potentially reducing the persistence of some substances, whereas increased flooding and storm surges remobilise "legacy" chemicals trapped in sediments, redistributing pollutants across ecosystems.

Shifts in Biodiversity and Sensitivity

Climate change influences the abundance and distribution of species potentially exposed to environmental chemicals. Species composition determines the sensitivity of assemblages and chemical-specific variation in species sensitivity drives variation in the relative sensitivity of those assemblages. Under the high-emission RCP 8.5 scenario, 76% of UK freshwater assemblages are predicted to become more sensitive to chemical exposure due to climate-induced changes in species composition.

The CITS and TICS Framework

The interaction between temperature and toxicity is bidirectional:

• Climate-Induced Chemical Toxicant Sensitivity (CITS): Warming can change the toxicity of chemicals by affecting toxicokinetic processes.

• Toxicant-Induced Climate Change Sensitivity (TICS): Exposure to pollutants can lower an organism’s resilience to climate stressors.

Biodiversity loss, climate change and pollution

The three major environmental threats facing the planet – biodiversity loss, climate change and pollution – are interlinked. Climate-chemical interactions can result in biodiversity loss, which in turn can affect environmental exposure and ecological receptors, creating feedback loops that exacerbates environmental degradation. Addressing the “triple planetary crisis” requires a holistic risk assessment strategy that accounts for the complex interdependencies between a climate change, pollution and biodiversity loss.

Lorraine Maltby from the Unversity of Sheffield talks about the implications of climate change for the ecological risk of chemicals

Key Reading

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