Polluted air disorientates bees, moths and other pollinating insects, who have increasingly difficulty perceiving the smell of flowers. The study, yet another showing how we are destroying our planet, was led byUniversity of Reading (United Kingdom) and does not seem to leave much room for different interpretations.
How the study was conducted and what it showed
Scientists analyzed 22 experimental studies on the effects that the air pollutants ozone (O3) and nitrogen oxides (NOx) have on pollinators and have shown that both substances make it more difficult for insects to locate flowers, altering the structure of the odorous molecules emitted by them.
In particular, high ozone levels reduce the effectiveness of pollinators by an average of 42%, while NOx they reduce it by 46%. In the presence of both pollutants, the average reduction was 68%.
Only a few studies, however, have examined the combined effect of the two pollutants and, in such cases, the additional damage resulting from their combination was lower than the averages suggested, as the two gases react with each other in the air, partially canceling each other’s effects.
Going into more detail, the authors report that specialized pollinators, which depend on the smell of a specific plant (such as some moths), are more at risk than generalists (such as many bees).
Diurnal pollinators, such as bees and butterflies, are also exposed to higher levels of ozone, while nocturnal pollinators (including many moths) encounter higher concentrations of nitrogen oxides. But still both need protection.
The last but not the leastmost of the evidence comes from Europe, leaving a gap (and a lot of fear) in understanding the risks to pollinators in more heavily polluted regions, such as some areas of Asia.
What we need to do to protect pollinators
As has long been known, diesel vehicles are the main source of NO pollutionx and can remain in circulation for over 20 years after the last new example is sold. For this reason, the postponement of the ban on the sale of new petrol and diesel cars – postponed from 2030 to 2035 – risks prolonging the damage to pollinators.
Ozone levels are expected to continue to rise until around 2050 even as NOx emissions begin to decline as the world transitions away from fossil fuels – explains James Ryalls, lead author of the research – This scenario presents a critical period for pollinators in the next two to three decades. Once cleaner fuels are fully adopted, ozone levels should drop, giving pollinators a chance to recover
But what will really happen is very difficult to predict.
The speed of this recovery will depend on the choices governments make today. Reduce NO emissions fasterxespecially those of diesel vehicles, could shorten the critical period and accelerate the recovery
While it is very easy to understand (or at least it should be) what happens if pollinators completely or partially stop pollinating.
Much of the food we grow depends on healthy pollinators: protecting them from pollution is therefore an urgency that cannot wait until 2050
The work was published on Frontiers in Ecology and the Environment.
Sources: University of Reading / Frontiers in Ecology and the Environment
