We all know about the huge declines in bee and monarch butterfly populations. Now, it turns out that in some areas nearly all insects are at risk of extinction. And if we don't solve this problem soon, the repercussions could be huge.

Insects are an important part of the global ecosystem. They not only provide important pollination services, but they also occupy an important place on the bottom of the food chain for many animals. Fewer insects means less food, leading to plant and animal population declines.

“The growing threat to [insects], which play an important role in food security, provides another compelling example of how connected people are to our environment, and how deeply entwined our fate is with that of the natural world,” said Achim Steiner, the executive director of the United Nations Environment Program, in a press statement.

One of the challenges is that insects are not well understood at an individual species level, because there are millions of insect species and only a limited number of insect specialists. Only about 20 percent of the world's insect species are cataloged, and the symbiotic relationships that many plants have with insects are rarely fully understood.

“Unfortunately, information on invertebrates in general, including insects, is very limited, restricted to a few groups and a few localities,” Rodolfo Dirzo, an ecologist at Stanford University, told Yale 360. He was the lead author of a 2014 study that was one of the first to document the fall in global insect mass.

So, what's causing the insect decline? In one word, us. The specific causes are likely very complex, but they are almost certainly connected to human impacts. It could be chemicals, like the pesticides class “neonicotinoids” that are connected to the bee declines. Or the growing number of rivers and waterways around the world that are polluted due to factory and agricultural run-off, or the still-growing number of pollutants we're putting into the atmosphere. But one thing is almost certain: We are to blame.

"Their decline is primarily due to changes in land use, intensive agricultural practices and pesticide use, alien invasive species, diseases and pests, and climate change,” said Sir Robert Watson, vice-chair of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, in a press statement.

Another oft-cited cause is the overuse of nitrogen fertilizer – something far too common in the monoculture corn fields of middle America. These corporate-driven, mono-culture farming methods are also to blame, as they limit the space for most insects and the plants to which they connect to survive.

Instead of waiting to discover the cause, we need to take immediate action now. That means reducing the number of chemicals we use, eliminating pollution and rapidly cutting back on greenhouse gas emissions, which also may be connected to what's happening. It also means reducing the scale of monoculture farming and returning to more natural, diverse, bio-dynamic farming methods that increase biodiversity.

Because if we lose insects, we'll soon lose a lot more.

Image credit: Uditha Wickramanayaka via Flickr