Avert insect apocalypse; global warming is killing many species

While the unusual weather pattern this year has brought our attention as well as that of the policy makers on the environmental fallout, and how it impacts the economy of the region, what we fail to visualise is the influence the global rise in temperature has on the behaviour and distribution of the insect species

On the last day of January, the upper reaches of Himachal Pradesh, Kashmir, Ladakh and Uttarakhand received the season’s first snowfall. Almost a month and a half late, a snowless winter at the time of a changing weather pattern raises concerns over what awaits the future in the Himalayas.

While we have seen images of empty ski resorts in the desolate Gulmarg valley in Kashmir and read reports of the cancellations of hotel bookings by tourists, the impact on agricultural production, water availability, reduced flow in the rivers and the dry winter impact on fruit crops have all been discussed, a comment by a local villager in Ladakh is what caught my attention.

“This year winter doesn’t feel like the same Ladakhi winter. It is very warm. This time we can see many insects such as housefly and butterflies alive in the peak of winter. It is very unusual for a place like Ladakh,” a local resident Kunchok Dorjai was quoted in the latest issue of Down to Earth magazine (Jan 25, 2024).

What he said made me think

First of all, this reminded me of the time when I was travelling to Europe to speak at international conferences on global warming; I would tell my hosts that the time is not too distant when as the climate gets warmer, the household insects you people despise, including mosquitoes and cockroaches, will be increasingly seen in the temperate climates. So brace up for the insect invasion, I would say.

While we would dismiss it in a lighter vein, the reality is now dawning.

Comes winter, and normally we find mosquitoes and houseflies disappearing. As the summer season begins, these insects are back. Studies show that as the weather gets warmer, insects are responding to climate change and moving north. The complexities of the ecosystem and the warming temperatures provide fascinating insights into how the insect world is responding to climate emergency that the world is faced with. Since the world has already moved from global warming to an era of global boiling, how the insect species will respond to harsher climates is something to be closely followed.

But if insects like houseflies and butterflies have been seen around in winters, it is not only unusual but needs a closer understanding of the changing insect behaviour. With more insect species moving northwards to escape heat; the time is not far when cockroaches and mosquitoes too will do likewise.

Anyway, while the unusual weather pattern this year has brought our attention as well as that of the policy makers on the environmental fallout, and how it impacts the economy of the region, what we fail to visualise is the influence the global rise in temperature has on the behaviour and distribution of the insect species. Although a lot is known about how a snowless winter deprives the apple plantations of the chilling temperatures requirement it needs in the winter months, and why apricots for instance have started blossoming early in winters.

The impact on birds and animals too is better understood for the simple reason because of its interaction with the human populations. For instance, studies at the University of Sassari and University of Ferrara in Italy have found that ostensibly to avoid being drained out Alpine goats in Europe are now going nocturnal. This is to avoid day heat but may invite other threats. Many bird species for instance have also started shrinking and in some other cases the wingspan of some bird species are increasing so as to help keep the body cool.

Coming back to insects, some studies show that with the normal habitat becoming inhospitable, many insect species, including butterflies, are shifting their migratory pattern. Habitat destruction has added to their woes.

A study by the University of Southampton found that the British butterflies are growing bigger. Another study by the University of Cambridge fear that smaller and light-coloured tropical butterflies may finally lose out as the temperature gets warmer.

Research also shows that the butterfly species usually found in the mountains respond to global warming by shifting their habitat to higher altitude. With increasing biodiversity loss, which is their natural habitat, mountain butterflies are shifting base and moving higher. Some researchers have found that in the Himalayas, butterflies have moved higher by about 300 metres. So it is not only apple plantations that have moved to a higher altitude because of rising temperatures; insect species, including butterflies, too are moving upwards.

On the other hand, as the region becomes hotter and dryer, hundreds of insect species in America’s west are vanishing. The International Union for Conservation of Nature (IUCN) has placed the monarch butterfly in the Red list of Threatened Species, the threat being both from habitat destruction and climate change. Studies have also shown that the wing span of monarch butterflies, which migrates annually for about 4,000 km, is getting bigger. Numerous other studies show that being sensitive to environmental changes, as the temperature increases, the wing length of the butterflies also grows proportionally. But some species have shown the wing length getting reduced as the temperature warms. It depends on how the insect species reacts to global warming.

In fact, climate resilience, adaptation and mitigation is not only confined globally to agriculture, it impacts the insect world a lot more. While the impact of changing climate on insect species is being studied widely, it still hasn’t entered the dominant narrative. Nor do we talk of climate resilience being demonstrated by the insect species, the same way as the growing focus is on mitigating the climate impact on food crops. While the economic fallout of huge impact climate change has on insect population may not be significant, the fact remains that insects remain a good indicator of the likely effects of climate change.

As the New York Times had once stated “they are not cute as polar bears but insects are critical to ecosystems and their decline should worry us.”

“Ultimately all insects, including butterflies, the world over are likely to be affected by climate change,” as Esme Ashe-Jepson of the University of Cambridge points out, the world cannot wait for an insect apocalypse to happen. The silence of the insects cannot be taken for granted anymore. It certainly is a race against time.

(The author is a noted food policy analyst and an expert on issues related to the agriculture sector. He writes on food, agriculture and hunger)