Kate Rowell, Grantham Institute and Imperial College Business School Master’s student studying Climate Change, Management and Finance, looks at why bees are suffering the impacts of climate change and what this means for global biodiversity and food security.
What’s the problem?
Three quarters of global food production relies on pollination to some degree, and for 5-8% pollination is vital. Similarly, 87.5% of the world’s flowering plants are also dependent on pollinators.
Of all the pollinators, bees are arguably our most important; responsible for pollinating a huge number of wild flowers, fruits, vegetables and nuts – including favourites such as almonds, apples and strawberries, which contain nutrients essential for human health.
But bee populations are in decline globally.
Bees and flowers enjoy a symbiotic relationship; bees need nectar from flowers for food, and flowers need bees to disperse their pollen and enable them to reproduce. A decline in one has a direct impact on the other, meaning that the decline in bee populations (both wild and farmed) is likely to have a huge impact on global biodiversity. And biodiversity is essential for food security, economic development and pharmaceuticals. In fact, it is estimated that biodiversity resources contribute to more than 40% of the world’s economy.
Perhaps the biggest concern associated with the loss of biodiversity is food security. With the human population anticipated to reach 9.7 billion by 2050, we need to ensure that there is sufficient food for everyone. In fact, the Food and Agriculture Organisation of the United Nations estimates that of the 100 crops that provide 90% of the world’s food, 71 are bee pollinated. Without these foods, the risk of malnutrition increases.
For example, a 2015 study, which looked at the impact of the loss of pollinators on nutrient deficiency in four developing countries, showed that up to 56% of populations would become at risk of being nutrient deficient, particularly in Vitamin A, which is essential for vision, healthy skin and immunity.
What’s climate change got to do with it?
Overuse of pesticides (neonicotinoids in particular), parasites, competition from invasive species and habitat loss are all contributing to the decline in bee populations. Add climate change to the mix and it’s no wonder they’re struggling – climate change both exacerbates existing problems and adds more of its own.
For instance, the changing use of vast areas of land to house and feed the ever-growing human population means that bees have lost much of their natural habitat, including nesting sites and the plants needed for their nutrition. On top of this, increasing temperatures due to climate change are reducing the area of land where bees can survive.
We might expect bees to shift their geographical range in response to increasing temperatures, as has been observed in other species, but worryingly, this does not seem to be case. A recent study showed that across the United States and Europe, bumblebees have lost nearly 300 kilometres from their range in the south without a corresponding shift in their range northwards. And this is only expected to get worse. Lead author of the study, Jeremy Kerr, gets straight to the point: “these species are at a serious risk from rapid, human-induced climate change”.
But that’s not all. It seems that climate change will also put bees at risk of encountering new pathogens that have adapted to climate change by expanding their ranges. For example, the parasite Nosema ceranae originates in Asia and has been linked to colony collapse. A 2014 study showed that it is now set to flourish in Europe as local temperatures rise and become more habitable for the parasite.
And if that wasn’t bad enough, climate change may also be disrupting the symbiotic relationship between bees and flowers by causing snow to melt earlier in the year. This means flowers open earlier, but bees are not necessarily emerging from hibernation earlier. As Rebecca Irwin, Associate Professor at the Department of Applied Ecology, North Carolina State University, explains below, we don’t yet know whether bees will be able to adapt quickly enough to match this shift in the timing of flowers blooming.
What is being done about it?
It goes without saying that we need to drastically curb carbon dioxide emissions in order to halt climate change, however this will take time and therefore other actions are needed in the meantime to give bees, and other pollinators, a helping hand.
The good news is that something is already being done. The United Nations has encouraged countries to “prioritise protection of pollinators to ensure food security”. Similarly, both the UK and the US have developed plans stop the decline of bees, and the EU has banned the use of three neonicotinoids across all member states. Hopefully, this is just the start.
At an individual level, there’s plenty you can do to help; why not plant bee friendly flowers in your garden, donate to Friends of the Earth’s ‘Bee Cause’ or take part in the Polli:Nation survey of the status of pollinating insects across the UK?
By protecting all our pollinators today, we can help ensure the world retains its rich biodiversity.