Smells Are Under Threat

Smells are all around us. What we know as a scent (气味) is a collection of natural or artificial airborne chemicals released from objects. But smell is often overlooked and undervalued. So, as climate change and biodiversity loss threaten natural scents, many people may not even notice.

Whether or not we pay attention to the world’s “scentscape”, heat and pollution are causing it to shift. As temperatures rise, man-made substances release more scent molecules (分子), and biodiversity loss due to climate change threatens the plants that scent the environment. “If you go to a forest, you have a given environment and temperature. If that temperature goes a little bit high, the profile of the chemical components in the air changes,” since temperature can affect the amount of smell-carrying gas particles (粒子) released from substances, explains John Smith, a chemical engineer. “And therefore, the perception of how the forest smells changes.”

That effect extends beyond forests. Snow — already threatened by a warming climate — absorbs different chemicals from the atmosphere as temperatures rise, which changes its cold-clean scent. Warmer conditions can intensify smells, leading the snow to smell more unpleasant and potentially gather more pollutants.

Climate change is also quickening the loss of biodiversity, threatening to erase certain smells entirely. When plants disappear, their scents become more difficult to produce.

Some scents are linked to cultural heritage. A recent study reported that native communities in Peru noticed a change in the smell of the Amazon River due to industrial pollution. Over generations, communities became desensitised to increasingly smelly rivers, a sign of broader ecosystem degradation. At the same time, in some Amazonian belief systems, declining water quality and the unpleasant smells will lead to the dispersal (消散) of the river’s spiritual beings. The damage to the scentscape could result in harm to both health and spiritual practice.

Even though we have other valuable things endangered by climate change, like food access, there is also an element of cultural identity, cultural survival, and history. If we don’t look at it, we lose all the richness behind it.