The Conversation: Reduce Agricultural Chemicals to Save Insects from Climate Change

Essay by Eric Worrall

If you have ever tried to grow a veggie garden, you will know first hand how much heartache a good drenching of bug spray can prevent. But deep greens appear to prioritise insects before humans.

Climate change triggering global collapse in insect numbers: stressed farmland shows 63% decline – new research

Published: April 21, 2022 1.12am AEST

Speed read

• The world may be facing a devastating “hidden” collapse in insect species due to the twin threats of climate change and habitat loss.
• UCL’s Centre for Biodiversity & Environment Research has carried out one of the largest-ever assessments of insect declines around the world – assessing three-quarters of a million samples from around 6,000 sites.
• The new study, published in Nature, finds that climate-stressed farmland possesses only half the number of insects, on average, and 25% fewer insect species than areas of natural habitat.
• Insect declines are greatest in high-intensity farmland areas within tropical countries – where the combined effects of climate change and habitat loss are experienced most profoundly.
• The majority of the world’s estimated 5.5 million species are thought to live in these regions – meaning the planet’s greatest abundances of insect life may be suffering collapses without us even realising.
• Lowering the intensity of farming by using fewer chemicals, having a greater diversity of crops and preserving some natural habitat can mitigate the negative effects of habitat loss and climate change on insects.
• Considering the choices we make as consumers – such as buying shade-grown coffee or cocoa – could also help protect insects and other creatures in the world’s most climate-vulnerable regions.

Long read

Insects are critical to the future of our planet. They help to keep pest species under control and break down dead material to release nutrients into the soil. Flying insects are also key pollinators of many major food crops, including fruits, spices and – importantly for chocolate lovers – cocoa.

The growing number of reports suggesting insect numbers are in steep decline is therefore of urgent concern. Loss of insect biodiversity could put these vital ecological functions at risk, threatening human livelihoods and food security in the process. Yet across large swathes of the world, there are gaps in our knowledge about the true scale and nature of insect declines.

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Insects are facing an unprecedented threat due to the “twin horsemen” of climate change and habitat loss. We sought to understand how insect biodiversity is being affected in areas that experience both these challenges most severely. We know they do not work in isolation: habitat loss can add to the effects of climate change by limiting available shade, for example, leading to even warmer temperatures in these vulnerable areas.

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Eighty-seven of the world’s major crops are thought to be fully or partially dependent on insect pollinators, of which most tend to be grown in the tropics. Cocoa, for example, is primarily pollinated by midges, a group of flies infamous for bedevilling camping trips in Scotland and other parts of the northern hemisphere. In fact, midges play a vital and under-appreciated role in pollinating the cocoa needed to make chocolate.

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Read more: https://theconversation.com/climate-change-triggering-global-collapse-in-insect-numbers-stressed-farmland-shows-63-decline-new-research-170738

There are plenty of insect species I’d like to eradicate. Imagine the relief humans and animals would enjoy, from bites and horrible mosquito borne diseases, if all the mosquitoes in the world were eradicated.

Obviously if the world killed all the pollinators we’d be in a heap of trouble, and I have a soft spot for spiders, which kill other insects. Maybe we could save the handful of midge species which do something useful, like midges which pollinate cocoa bean flowers.

But there are plenty of agricultural pests the world wouldn’t miss – like carrot fly, a subtle pest which infiltrates root vegetables and ruins them, unless you spray deadly chemicals at just the right time. Nothing seems amiss until you try to pick the mature vegetables, and discover they are all rotten (see top of page).

Yet if greens get their way, entire harvests could face this kind of ruin, if farmers are too worried about legal protection for insects to do what they know must be done to protect our food supply.

Given the rising risk of food crisis caused by the Ukraine conflict, in my opinion it would be hard to pick a worse time to agitate for a reduction in use of agricultural chemicals.

Update (EW): Fixed a few typos.