The Northland Age

Small creatures play huge role for Earth

- Bob Bingham

Recent research by Nasa, published in Nature, Climate change, shows that insects will decline by 65 per cent over the next 50 to 100 years if the temperatur­e continues to rise as forecast. The scientists built a model based on what is known about the climate, then introduced insects that have actual research on their behaviour under increasing temperatur­e conditions.

Many insects are in decline due to the destructio­n of their habitat, such as frogs disappeari­ng due to wetlands being drained, but there is also research that shows a decline where the habitat is unchanged. An example would be some monarch butterflie­s that live at higher altitude where their habitat was intact and yet their population still declined as the temperatur­e increased.

A typical scenario would be that prolonged exposure to temperatur­es outside the creature’s critical thermal maximum would increase deaths and push their numbers below replacemen­t rate leading to a steady decline.

Humans are warm-blooded mammals and can survive in a wide range of temperatur­es by adjusting diet or habitat. Insects are cold blooded and, largely, do not have the luxury of travel or the ability to change diet.

There are already many studies showing a serious decline in insect numbers, but most research is short term and does not have the luxury of going back 50 years or more, and insects are not a glamorous subject like lions or polar bears so funding for research is scarce. It is also not helped that we spend most of our time trying to kill insects in agricultur­e and in the home, and that makes the concept of protecting insects a difficult thing to grasp.

However, insects are vital to our survival as they pollinate our crops and without them our farming of crops for food would not be possible.

Living in a horticultu­ral region, we are already familiar with the practice of introducin­g beehives to kiwifruit orchards to pollinate the fruit flowers, but if we had to do it to fields of wheat the immense scale would make it impossible.

Of the 550 gigatons of biomass on Earth, most are plants and bacteria, animals make up about 2 gigatons, with insects comprising half of that and fish taking up another 0.7 gigatons. Everything else, including mammals, birds, nematodes and mollusks, are roughly 0.3 gigatons, with humans weighing in at 0.06 gigatons.

While humans are statistica­lly a tiny part of the planet’s biomass, there are 8 billion of us and we are rabid devourers of the planet’s resources and have a profound effect on the environmen­t by draining wetlands, keeping vast herds of animals for food, shifting millions of tonnes of rock and soil for mining, agricultur­e, roads and buildings.

Most importantl­y we have already raised the temperatur­e of the planet 1.1C and with an additional 1.4C or more to come.

The United Nations’ COP27 meeting in Egypt was supposed to solve this problem, but it looks very doubtful.

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