How to stop insect apocalypse

We often pay little attention to insects unless one happens to bite, sting or generally bother us. But lately, they've become an unlikely source of nostalgia.

People have started to notice their absence, reminiscing about unwittingly swallowing tiny flies while cycling through the countryside, about car windscreens splattered with dead bug bodies at the end of a long journey or moths flocking to the light when a window was left open.

And science is backing up such anecdotal observations. A recent study published in the journal Biological Conservation says insects are hurtling down the path to extinction.

More than 40 percent of species are in decline and a third is endangered, the analysis found. Worldwide, we lose 2.5 percent of insect biomass each year, and if numbers continue to fall at their current rate, there could be no insects left in 100 years.

The results are "shocking," says Francisco Sanchez-Bayo, environmental scientist at the University of Sydney and co-author of the study. He predicts "catastrophic consequences."

"The word catastrophic is appropriate because the disappearance of insects brings with it the starvation of myriad vertebrates that depend on them, and therefore the collapse of entire ecosystems," he told DW.

Read more: 'We cannot survive without insects'

Insects don't only play an important role in our food production, by providing a free pollination service, but are themselves food for all kind of animals. Without bugs, amphibians and birds would starve to death and fish would struggle to find enough to eat.

The six-legged helpers also clear away carcasses of animals that die in the wild and decompose plant waste. Without bugs, life as we know it would come to a halt.

But is it too late to stop an insect apocalypse? Read on for three main drivers of insect declines and possible solutions.

Intensive agriculture is bug-unfriendly

According to the meta analysis, the steepest declines in insect biomass have occurred in the past 30 years. Sanchez-Bayo says this is the direct result of agricultural intensification.

The Green Revolution of the 1950s and 1960s changed the way farmers tended their fields. Fallow practices were abandoned, monocultures were developed and artificial fertilizers were introduced as a means of avoiding nutrient depletion in the soil.

Insecticides and herbicides became common features of pest and weed control, and trees and hedgerows were eliminated to generate more space.

Though this resulted in a huge gain in yield, it also implied a loss of insect habitat and led to chemical residues contaminating nearby waters.

Sanchez-Bayo says the world needs to change the way it grows food. One way forward could be a farming method known as Integrated Pest Management (IPM), which combines traditional agricultural practices with modern technologies.

"IPM advocates the use of natural means of pest and weed control, rotation of crops to maximize biodiversity of beneficial insects and avoid nutrient depletion, and only uses pesticides as the last tool to control a pest or weed outbreak," Sanchez-Bayo told DW.

By way of example, he cited the International Rice Research Institute in the Philippines, which managed to reduce the use of insecticides in rice crops by 93 percent without losing yields.

Climate change could cause major insect wipeout

Although intensive agriculture has been identified as the main driver for insect declines in Europe, scientists say the main culprits in other parts of the world are climate change and deforestation.

Even in pristine, virgin tropics, far away from fertilizers, pesticides and insecticides, insect numbers have steadily dropped.

In Puerto Rico's Luquillo rainforest, for example, there are as many as 60 times fewer insects now than there were in the 1970s. During the same period, forest temperatures have risen 2 degrees Celcius (3.6 degrees Fahrenheit). The number of lizards, frogs and birds that eat insects has declined synchronously.

Read more: Climate change threatens half of wildlife in biodiversity hotspots, study says

Calculations by researcers at the Tyndall Centre for Climate Change Research highlight the correlation between global warming and insect survival.

Their projections suggest that if we experienced global warming of 3.2 degrees Celcius above preindustrial levels, as is likely on the basis of current pledges made under the Paris Climate Agreement, 49 percent of insects would lose half of their geographic range.

If we limited warming to 2 degrees Celcius above preindustrial levels, 18  percent would lose half of their range. In a 1.5 degree scenario, however, the number would drop to six percent.

Rachel Warren, lead author of the study, says it's very possible that population decreases would actually be even larger than projected because they didn't factor such things as intensive agriculture into their calculations.

"It's no question that there are many pressures on insects and if we don't achieve the goals of the Paris Climate Agreement, there will be another big pressure on them," Warren told DW.

She says it's not only important that we manage to achieve the 1.5 C degree goal, but how we achieve it.

"Land availability is a major factor for insect losses. If we use too much land to grow plants for biomass energy, that would be bad for biodiversity," she explained. "So anything we can do to reduce our energy and land demand, such as using less power and eating less red meat, is great."

Urbanization — let your garden grow wild

Big cities and concrete landscapes also play a significant role in insect numbers, and with two-thirds of the global population expected to be living in urban areas by 2050, that impact is set to grow.

Densely built neighborhoods and sealed, concrete roads strip bees and bugs of their natural habitats, while light pollution leads nocturnal insects astray.

Researchers are therefore calling on governments to create more green spaces in cities by rewilding public parks and private gardens, and planting wild flowers along roadsides and on traffic islands.

A study by the University of Basel in Switzerland found that nature-friendly gardens, with deadwood, compost, unmowed grassland and native flowers, can greatly increase the biodiversity of flying and soil-dwelling insects and largely compensate for the negative effects of urbanization.

The wilder and more diverse the gardens, the more insects the researchers counted, including rare millipedes that have not yet been found anywhere else in Switzerland.

Brigitte Braschler, biologist at the Universtiy of Basel and co-author of the study, has been researching insects her entire life and says that although the decline in biodiversity "is very strong", it's not too late to change the trend.

"The public is waking up to the problem and is willing to act. Certain species are already lost but I'm positive we can stop the decline or at least slow it down," Braschler told DW.