Countries most susceptible to toxic pollution are also at highest risk from the impacts of global climate change

By James DuckerReviewed by Emily Henderson, B.Sc.Jul 19 2021

Mapping the global distribution of toxic pollution alongside the effects of climate change shows the same countries are most vulnerable to both.

Study Results. Image Credit: Marcantonio et al, 2021, PLOS ONE

Mapping and understanding the associations between sources of anthropogenic stress

Human activities are destabilizing natural systems and previous research has shown low-income countries face higher risks than high-income countries from toxic pollution and climate change; however, little research has explored the relationship between these two risks.

Now, a new global analysis in the journal PLOS ONE by Richard Marcantonio from the University of Notre Dame, Indiana, USA, and colleagues show that specific low-income countries are significantly more likely to be impacted by both toxic pollution and climate change.

The researchers explored the countries at risk from both stressors by collating and analyzing 3 frequently used public datasets, ND-GAIN (Notre Dame Global Adaptation Index), EPI (Yale Environmental Performance Index), and GAHP (Global Alliance on Health and Pollution), using data for 176 countries from 2018.

To test the relationship between toxic pollution and climate change, researchers used Spearman’s Rank-Order Correlation Coefficient and Pearson’s Correlation Coefficient, which was then followed by a target assessment of pollution mitigation in specific countries. The latter was calculated using an equation incorporating measurements of vulnerability and readiness to stressors.

Strong link between climate risk and toxic pollution making specific countries particularly vulnerable

Researchers found a strong and significant relationship between the spatial distribution of global climate risk and toxic pollution. This means that countries most at risk for impacts of climate change were most often also the countries facing the highest risks of toxic pollution.

This is particularly concerning as both stressors also act in synergy with climate change and toxic pollution reinforcing one another. For instance, warming temperatures increase toxic pollution which in turn increases greenhouse gas retention that increases warming.

When researchers considered which countries would be most affected, they found that the top one-third of countries most at-risk represented over two-thirds of the world's population, geographically concentrated in low-income countries across Africa and Southeast Asia.

Researchers then created a "Target" list of the top ten countries that could provide maximum returns on any investment for risk reduction based on their risk as well as their structural capacity to implement changes. This included a range of countries across Southeast Asia, and advice was focused on where best to address toxic and non-toxic pollution together based on the need to limit consequences for humans and maximize return on effort.

The combined findings and recommendations support the evidence indicating demographic, ecological, and social factors at work are interconnected and demonstrate broader patterns of inequality. Moreover, it also emphasizes that physical geography, local structural conditions, and external factors play a fundamental role in exacerbating or limiting risks to anthropogenic stress in these countries.

However, the data in this study does not consider all impacts derived from anthropogenic stressors or the potential synergistic risks of both pollution and climate change, as data was only collected from the initial public datasets. Moreover, the authors also noted that intra-country assessments require further refining to address impacts since risks can vary widely.

Nonetheless, the findings provide clear indications for a need to address the effects of pollution and climate change globally, while also suggesting an approach for policymakers.

Vast work has been done to understand the magnitude and distribution of risk from climate change and toxic pollution, separately. We wanted to know if the spatial distribution of these two types of environmental risks are similar and, unfortunately, our results say that in general, they are."