Climate change has been called by some as the greatest threat to human health in history. This blog takes a look at some of the implications for pest control that are being caused by climate change.
In October 2018 the United Nations Intergovernmental Panel on Climate Change (IPCC) published “Global Warming of 1.5C.” in which they concluded that all life on this planet is under existential threat from global warming and climate change.
What differentiates climate change from natural weather variability is the long-term view: the Natural Resources Defence Council (NRDC) defines climate change as a “significant variation of average weather conditions over several decades or more”.
And while “climate change” and “global warming” are often used interchangeably, global warming—the recent rise in the global average temperature near the earth’s surface—is just one aspect of climate change.
So what do increasing temperatures mean for human health?
NASA, on the climate change section of their website, states that the “effects that scientists had predicted in the past would result from global climate change are now occurring: loss of sea ice, accelerated sea level rise and longer, more intense heat waves”.
And some of the long term effects of global climate change that we can expect to see are:
- A continued rise in temperature
- Changes in rainfall patterns, with a trend towards heavier storms and stronger hurricanes
- More intense droughts, heat waves and fires
- Rising sea levels of up to 8 feet by 2100
- An ice-free Arctic (over summer) by mid-century
But what does this have to do with pest control?
Climate change is also predicted to profoundly influence the population dynamics of insect pests as temperature has a direct influence on insect reproduction. The deadly combination of increased C02 levels and global warming could mean that areas which are currently uninhabitable for pests could soon become fertile breeding grounds.
Not only do most pests breed better (and faster) in warmer temperatures but some species tend to grow bigger and increase their resistance to insecticides. For an example of how breeding time is accelerated by warmer temperatures, one has to look no further than the common house fly. At temperatures of 30 degrees the entire fly breeding cycle can take as little as 10 days!
Furthermore, for most species an increasing temperature is likely to lead to a higher survival rate during winter months.
Increase in vector borne diseases:
Vector-borne infectious diseases, such as malaria, dengue virus, Zika virus and Lyme disease affect nearly half of the world’s population, and can create international public health emergencies. The outbreak of Zika virus, which was spread mainly by mosquitoes during 2015-16, was widely linked to global warming by the scientific community, following a spell of unusually high temperatures.
The Asian Tiger Mosquito, a known vector of dengue virus, chikungunya virus and dirofilariasis, is a species native to Asia. However, due to increasing temperatures, the mosquito is now spreading rapidly across Europe and the US where it is now present in 32 states.
Increased pest risks to the food supply:
With the global temperature expected to increase by around 2°C (35.6°F) in the next few decades, we can expect to see pests migrate to cooler climate environments. This could result in insects becoming a bigger threat to food safety and production, as they become more resistant to insecticides and experience additional generations.
The Coffee Berry Borer (Hypothenemus hampei), the most important pest of coffee worldwide, is now present in virtually every coffee-growing region in the world including Hawaii, and is a key example of this effect in action. It is estimated that the beetle causes $500 million in damages to coffee growers each year. Th beetle has already benefited from the temperature rise in East Africa as increased damage to coffee crops and expansion in its distribution range have been reported. Until ten years ago, there were no reports of coffee berry borer attacking coffee plantations above 1,500 m, which is within the preferred altitude range of cultivated and naturally occurring C. arabica. However, due to recent increasing temperatures in coffee growing regions in the world the insect can now be found also at higher altitudes, where it is able to infest C. arabica.
The Brown Marmorated Stink Bug (BMSB) is a pest we have written about quite regularly on this blog (read more about them here). Originally from East Asia, the BMSB is an invasive pest that is present throughout much of the United States, although Europe has had its fair share of BMSB invasions and is trying to recover from record invasions. BMSB is a serious economic threat to fruit crops, garden vegetables, and many ornamentals. In a changing climate, agricultural losses from insect pests like BMSB are expected to increase, as CLIMEX simulations indicate that BMSB will benefit from ongoing rising temperatures by expanding its range and increasing the number of generations produced per year.