Scientists map how industrial activity is distorting nature’s scent

A growing body of research suggests that human activity is not only reshaping ecosystems through climate change and pollution, but also altering one of nature’s most fundamental communication systems: scent.

New found evidence has opted scientists to warn that air pollution, rising temperatures, and the widespread use of fertilizers and fungicides are changing the chemical signals that plants and animals rely on to interact, as documented in an article published by the Yale University's School of the Environment. 

As one scientist put it, while humans tend to rely primarily on sight and sound, much of the natural world is still governed by smell — and that invisible language is now under growing pressure from human activity.

These disruptions could have far-reaching consequences for insect reproduction, navigation, foraging behaviour and even the pollination of key food crops.

The phenomenon is part of what researchers call “smellscapes” — the combined network of scents that define a particular environment. Although the concept was first introduced in the 1980s, scientists are only now beginning to understand how rapidly these chemical landscapes are being transformed.

In Egypt, rising temperatures are reducing yields of fragrant jasmine used in the perfume industry. In France, extreme droughts have diminished production of night-blooming tuberose, another key perfume ingredient. In Italy, climatic extremes are altering the characteristic citrus and floral profile of bergamot, a cornerstone of the fragrance industry.

However, researchers say the deeper concern lies not in commercial fragrance alone, but in the invisible ecological role of scent. Many species depend on chemical signals to survive. Bees and moths use floral odours to locate nectar sources, while flies and dung beetles rely on scent cues to recycle nutrients from decomposing matter — processes that underpin soil health and agriculture.

Intact chemical communication systems are also crucial for biodiversity. Some orchid species, for example, depend on precise scent signals to attract specific pollinators, while monarch butterflies rely on plant odours to locate suitable egg-laying sites.

As researchers increasingly map these systems, they are finding that human activity can significantly distort them. Air pollution, for instance, can break down volatile organic compounds (VOCs) that form the basis of many plant scents, while heat stress can reduce the intensity of floral emissions in species such as strawberries and wild petunias. Agricultural chemicals further complicate this picture by introducing additional VOCs into the air in farming regions.

Jeff Riffell, a sensory biologist at the University of Washington, is cited in the article, noting that  odour pollution has been far harder to study compared with noise or light pollution due to the complexity and cost of measuring airborne chemicals.

Despite these challenges, researchers are increasingly documenting how changing atmospheric conditions are reshaping scent-based communication systems worldwide — and raising questions about which species can adapt, and which may be pushed toward ecological failure.

Air pollution, for example, has been found to degrade many of the volatile organic compounds (VOCs) that make up lavender’s characteristic scent, while increasing temperatures have led to dramatically decrease the floral perfumes released by strawberry plants and wild white petunias. At Agricultural chemicals, like fertilizers and fungicides, add additional VOCs to the air in fields and orchards around the world.

By Nazrin Sadigova