Why are Bees Dying? Climate Change and the Pollination Problem

Read time: 5 mins
Why are Bees Dying? Climate Change and the Pollination Problem

Pollinators provide essential ecosystem services for our planet, but they are not immune to the effects of climate change. In fact, pollinator numbers have been dropping in recent years, directly reflecting major habitat alterations as a result of our changing climate.

More than three-quarters of Earth’s flora, including the majority of our food crops, rely on birds, insects, bats and other animals for reproduction to successfully occur. Studies have found that 87% of fruit, vegetable and seed production (35% of global food) depend on animal pollination.

Pollinators come in many different shapes and sizes and morphological characteristics will dictate which pollinator-plant pairs are able to effectively cross-fertilize. Honeybees, for example, are generalist pollinators that can feed on most plants due to their unique morphologies that allow them to “fit” with different species, and therefore provide pollination for a wide range of flora. Because of this unique characteristic, honeybees are responsible for pollinating over 90 commercially grown crops in North America. This makes them one of the most important insects in our food system.

After their numbers began to drop in 2005, honeybees had to be imported and “managed” to ensure crop vitality. The initial cause for declining honeybee populations is under debate, although it appears that honeybees and plants fell out-of-sync, responding differently to habitat changes that had been occurring. Honeybees were then imported and managed as a solution to this problem, but in recent years the honeybee population is in danger once again.

A study conducted by the Committee on the Status of Pollinators in North America (2016) revealed yet another pattern of tumbling numbers in managed honeybee populations. This time, the waning population was attributed to increases in parasites and diseases within the honeybee hives, resulting in a long-term downwards trend. Pathogens appear to have originated from imported honeybees since 2005, which could possibly spread to wild honeybees and other pollinator species. The most recent statistics reveal a population collapse of over 40% (USDA 2015). This study attributed pesticide use to causing fatalities in managed bee colonies.

Because of this, pollinator-plant interactions have become a recent hot topic in the scientific community, with scientists across the globe agreeing that one cannot survive without the other. What scientists have not been able to identify is whether or not adverse changes to our food systems may arise if pollinators and plants fall out of sync due to climatic changes. In the past, pollinators and plants have co-evolved. Plants provide pollinators food, while pollinators provide plants with the opportunity to reproduce. For example, some insect life cycles have evolved to perfectly mirror plant maturity, with larvae maturing to adulthood when plant nectar begins to flow.

This complex relationship is not entirely understood as it remains unclear what environmental or genetic signals direct this synchrony. Some plant-pollinator pairs do not respond to the same environmental cues and, as ecosystems change over time, the pair may become out of sync and unable to achieve pollination. Migratory pollinators, such as hummingbirds, seem to be particularly at risk for this phenomenon since temperature changes often alter migratory patterns.

As global temperatures are rising, bird migration patterns have already been altered. If plants and pollinators have different responses to a changing climate, there is no guarantee they will remain in sync in the coming years. In fact, spatial and temporal mismatches in plant-pollinator pairs are fairly common when studying the effects of climate change on crop pollination. As global climate continues to warm, there has been a pole-wards movement of native pollinator species. Since crops remain in their respective environments relative to pollinator movement, the natural pollination effect is diminished.

If global temperatures continue to rise, pollinators (and, by extension, global food production) are in serious danger. There are a few things we can do to help! Try out these methods for ensuring the safety of pollinators:

  1. Buy Organic:

  • Try buying food that is free from the pesticides that harm bees. This is the best thing we can do to keep our buzzy buddies thriving!

  • Pesticides classified as “neonicotinoid pesticides” are especially harmful to bees and have been linked to hive deaths in multiple studies, as well as negatively affecting other wild pollinators. Once neonicotinoids are applied, it spreads over every part of the plant– including the pollen. These pesticides are used over most corn crops, as well as soy, wheat and canola seeds.

  1. Buy Smart:

  • Lowe’s has announced that they will be putting a ban on selling bee-killing pesticides to protect pollinators! This is a significant eco-friendly movement for large-scale gardening retailers. Their commitment also includes a redoubling of pesticide management efforts and an application reduction plan. They have even committed to an increase in consumer education initiative and funding for pollinator gardens in an effort to rebound the pollinator population.

  • Some garden centers have followed Lowe’s lead by either labeling neonicotinoid-free plants or by phasing them out all together. Before you plant, ask your local garden center which of their products are safe for bees!

  1. Buying Local:

  • Supporting local sustainable agricultural practices can increase the number of wild pollinators drawn to the healthy ecosystem in your area. This is especially true for honey – buying honey from local beekeepers that care about the health of their bees ensures that you are protecting a hive.

You can even try taking it one step further by planting your own gardens to attract pollinators. The more local pollinators available, the less imported and managed pollinators needed! This limits the possibility of pathogen introduction to natural systems, protecting wild pollinators. Sunflowers, Echinacea and BeeBalm are especially popular choices for pollinator pals! Let’s face it; the bees need our help!



Carl Zimmer. The New York Times: 2 Studies Point to Pesticides as a Culprit in Declining Bee Populations (2012). Available at http://www.nytimes.com/2012/03/30/science/neocotinoid-pesticides-play-a-role-in-bees-decline-2-studies-find.html?_r=0

Food and Agriculture Organization of the United Nations. Climate Change and Crop Pollination. Available at http://www.fao.org/docrep/014/i2242e/i2242e01.pdf

Friends of the Earth Canada. The Bee Cause. Available at: http://foecanada.org/en/the-bee-cause/

Lorraine Chow. U.S. Honeybee Population Plummets by More Than 40%, USDA Finds (2015). Available at http://ecowatch.com/2015/05/14/honeybee-population-plummets/2/

National Research Council of the National Academies. Status of Pollinators in North America (2007). Available at http://www.nap.edu/read/11761/chapter/1.

Rebecca Lindsey. NASA Earth Observatory: Buzzing about Climate Change (2007). http://earthobservatory.nasa.gov/Features/Bees/bees.php

Stephanie Spear. Lowe’s to Stop Selling Bee-Killing Pesticides to Protect Pollinators (2015). Available at http://ecowatch.com/2015/04/10/lowes-neonicotinoid-pesticides/


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