The modern city is home to two crises: mental health that collectively unravels, and climate change that threatens ecological catastrophe. Authors and scientists alike have then spoken of the great outdoors as a landscape offering emotional and mental relief. The verdant greenery evidently benefits mental health and makes the person happier, a growing body of research shows; relying on psychological, biological, and cultural explanations.

Yet, something is amiss. Are these proposed links universal? If so, is the symbiosis between nature and mental health sufficiently explored in the context of racial, ethnic, and gendered disparities? That doesn’t seem to be the case; most scientific undertakings favor the experiences of rich, white, educated people living in western societies, according to a recent analysis. The blind spot overlooks more than 70% of the global population.

Published in the journal Current Research in Environmental Sustainability last week, the research looks at the diversity gap across 174 peer-reviewed papers exploring two facets of modern life. A jarring 95% of research was conducted in high-income western nations — the U.S., Europe, and East Asia. And of the participants whose ethnicity was documented, most were predominantly white. Investigations from medium- and low-income countries, such as India, remain grievously absent; accounting for only 4% of the research. Only one study spotlights mental health and nature’s relationship in the entire continent of Africa; a similar proportion applies to South America.

The severity of the bias is only beginning to be understood. It frames the concerns of mental health, climate change, and industrialization as those suffered by only a select few; leaving out billions of people who shoulder a disproportionate impact of both development and natural catastrophes.

“This field has great potential to address urgent issues—from the global mental health crisis to sustainability efforts worldwide—but to do so, we must better reflect the diversity of world’s populations, cultures, and values,” said lead author Dr. Carlos Gallegos-Riofrio in a media release.

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Two issues become of note here. One, does the lacking diversity discount existing research around nature’s benefits on mental health? Not quite; proximity to nature may indeed help alleviate depression and uplift mood. “There’s nothing necessarily wrong with the existing findings, those findings are important, but we have reason to believe they may not apply to the entire population,” said co-author Rachelle Gould, a researcher at the University of Vermont’s Rubenstein School of Environment and Natural Resources. While caucasian white people may benefit by going to the park, does the same relationship apply to indigenous communities in South America?

Two, there is a glaring Western bias in this scientific scrutiny. In 2010, evolutionary biologist Joseph Henrich coined the term “Weird psychology.” The acronym “WEIRD” when spelled out referred to wealthy, educated, industrialized, rich, and democratic parts of the world. Henrich argued that data accumulated based on WEIRD trials cannot be used to draw blanket conclusions. “This research strikingly demonstrates a massive bias in the sampling of global populations towards those that are Weird,” said evolutionary biologist Joseph Henrich, who was not involved in the study. “This limits our ability to generalize about the phenomenon under investigation.”

Climate change and mental health, while enduring issues that appear to affect society at large, have cultural-specific links. In order to fully tap on what nature can offer to people, and vice-versa, these nuances deserve to be explored. In knowing what effects of nature are universal — and what cultural — the pursuit towards sustainability becomes more precise.

As Gould added: “A more inclusive and diverse field that embraces the research needs of the global community — and the full spectrum of ways that humans interact with the non-human world — will ultimately be more impactful.”