Does the impact of climate change have a disproportionate impact on vulnerable groups?

Background

Climate change is now recognised as the largest threat to global health, fundamentally reshaping our world. Climate change has intensified the frequency and severity of weather events like hurricanes, floods, wildfires, heat waves, and droughts.

The impact of these events on physical health are well-documented, but less is know about the impact of climate change events on mental health. It is important to acknowledge that climate change events do not impact all groups equally, but it is the historically marginalised and vulnerable groups that are often more severely impacted and have fewer resources to recover after a catastrophic event. This large burden of climate change events on vulnerable groups amplifies the high risk for mental health problems they already experience.

Why did we do this research?

We did this review to summarise the research that has looked at the impact of climate change events on the mental health of vulnerable groups

What did we do?

We conducted a systematic review focused on three core concepts:

Exposure - climate change events: We categorised climate change exposures into three groups:

• acute weather events like hurricanes, floods, wildfires, and heat/cold waves

• sub-acute events like droughts,

• gradual changes like global temperature increases/decreases, sea level rises, or permanently altered environments

Outcome - mental health outcomes: We used linked health care records to look at diagnosis of major psychiatric disorders, including

• general mental health

• psychological distress

• symptoms or diagnosis of a mental disorder like depression, anxiety, post traumatic stress disorder, or severe mental illness.

Vulnerable populations: We focused on four vulnerable populations:

• low socioeconomic status groups (e.g. those living in poverty)

• minoritised ethnic or racial groups

• Indigenous groups

• housing-insecure or homeless groups

Analysis: We searched five databases. All titles and abstracts were screened by two independent reviewers, followed by full-text screening by these reviewers. We calculated the level of agreement between these reviewers and any disagreements were discussed with a third independent reviewer to reach consensus.

We extracted detailed information from each included study, before doing a quality appraisal and narrative synthesis of the findings.

What did we find?

We included 32 studies in this review, most of which focused on acute weather events and low socioeconomic status populations.

We found that vulnerable groups generally experienced worse mental health outcomes following climate change events compared to other populations, although some studies found mixed or null events.

Importantly, we identified critical evidence gaps, including limited high-quality research on sub-acute or gradual climate change events, Indigenous or housing-insecure groups, and research from low-and-middle-income countries.

What does this mean?

Overall, vulnerable groups experience worse mental health after exposure to climate change events, however, there are large gaps in the evidence which means we cannot fully understand the relationship between social inequality and the mental health impact of climate change.

Read more

You can read the full paper here BMC Psychology.

Read a short news stury on the Science Magazine.

Open science

Pre-registered protocol: PROSPERO Pre-print: OSF

Behind the research

This systematic review was led by Ridha Mahmood as part of her MSc dissertation in the UCL Division of Psychiatry. Justina (Liying) Cao, another MSc student in her cohort was the second reviewer. Pip Clery, Justin Yang, and myself provided academic supervision for the project.